Shunt Resistance For Mics

[David Aguilera[_2_]]

Scott,

You mentioned this the other day:

> [snip]
>
>Buy some of the old classics. Everyone should have an SM-57, an EV
>635A, and maybe an RE-20. The first two are very cheap, and all three
>can be found used. The first two are very touchy about loading and
>will benefit from a shunt resistor in a barrel connector if you are
>using a modern transformerless preamp.
>
> [snip]

I'm just getting into the electrical side of this field and am really
curious as to how to go about building the shunt resistor. If you have
the time to enlighten me I would greatly appreciate it.

The preamp I am using is not giving me what I want out of my 57's and
EV635A. I've always thought it was an impedance problem, but If I could
build a box with switchable resistance...well--wow! That's
straightforward and downright useful!

I don't have a anything that will measure impedance, so I am unsure of
the impedance of my preamps. Is there a way to measure it with a my
multimeter sans one?

After that it's like connecting resistance in serial right (I'm really
weak in AC electronics)?

Thanks,

David

[John Williamson]

David Aguilera wrote:
>
> I don't have a anything that will measure impedance, so I am unsure of
> the impedance of my preamps. Is there a way to measure it with a my
> multimeter sans one?
>
The input impedance of your preamp will be quoted in the manual. It will
be made up of capacitive and resisitive components for a transformerless
preamp, or capacitive, resistive and inductive components if there is a
transformer present. It's normally just quoted as "X ohms", though, as
if it were purely resistive.

> After that it's like connecting resistance in serial right (I'm really
> weak in AC electronics)?
>
No, a shunt resistor goes in parallel with the load. The easiest way to
make the unit you need is to connect a resistor across the signal. Make
up a short XLR-XLR extension lead, and solder a resistor between pins 2
and 3. Changing the resistor value will change the sound of older
microphones. For setting up, start with a 2 Kilohm variable resistor,
adjust it until you get the sound you like, then replace that with the
nearest value of fixed resistor. Use a low inductance metal film
resistor, preferably a one percent tolerance type. Carbon resistors have
more noticeable self noise.

--
Tciao for Now!

John.

[David Aguilera[_2_]]

John Williamson wrote:
> David Aguilera wrote:
>>
>> I don't have a anything that will measure impedance, so I am unsure of
>> the impedance of my preamps. Is there a way to measure it with a my
>> multimeter sans one?
>>
> The input impedance of your preamp will be quoted in the manual. It will
> be made up of capacitive and resisitive components for a transformerless
> preamp, or capacitive, resistive and inductive components if there is a
> transformer present. It's normally just quoted as "X ohms", though, as
> if it were purely resistive.
>
>> After that it's like connecting resistance in serial right (I'm really
>> weak in AC electronics)?
>>
> No, a shunt resistor goes in parallel with the load. The easiest way to
> make the unit you need is to connect a resistor across the signal. Make
> up a short XLR-XLR extension lead, and solder a resistor between pins 2
> and 3. Changing the resistor value will change the sound of older
> microphones. For setting up, start with a 2 Kilohm variable resistor,
> adjust it until you get the sound you like, then replace that with the
> nearest value of fixed resistor. Use a low inductance metal film
> resistor, preferably a one percent tolerance type. Carbon resistors have
> more noticeable self noise.
>

Thanks John!

[Mike Rivers]

David Aguilera wrote:

> I'm just getting into the electrical side of this field and am really
> curious as to how to go about building the shunt resistor. If you have
> the time to enlighten me I would greatly appreciate it.

Make up a short (1 foot or so) mic cable with a resistor connected between
pins 2 and 3 of the XLR connector on one end.

> The preamp I am using is not giving me what I want out of my 57's and
> EV635A. I've always thought it was an impedance problem, but If I could
> build a box with switchable resistance...well--wow! That's
> straightforward and downright useful!

Actually, at the Summer NAMM show, I saw someone who made a box
just like that. But honestly, if you're not getting what you want form your
SM57s or 635s, it's probably not the preamp. The 600 or so ohm load
across an SM57 cleans it up noticeably but it doesn't make it "warmer" or
"more transparent" or any of those other feelgood terms.

> I don't have a anything that will measure impedance, so I am unsure of
> the impedance of my preamps. Is there a way to measure it with a my
> multimeter sans one?

Yes, but it's more complicated than just hooking it across the input
terminals.
What you need to do is put a variable resistor (pot) in series with a
generator and
connect it to the input. You'll want to connect the generator between
pins 2 and 3, or
between pins 2 and 1, with pin 3 grounded (connected to pin 1).

Fire up the generator and measure the output voltage with the variable
resistor at
zero ohms, making sure you're not driving the preamp into clipping with the
generator. Then adjust the pot so that the voltage drops to half what
you measured
with no resistance in the circuit. Then measure the resistance of the
pot. That's
half the input impedance.

[LAB]

>> Then adjust the pot so that the voltage drops to half what you
measured with no resistance in the circuit. Then measure the resistance of
the
pot. That's half the input impedance.

If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen Rin=Rpot. Why the
half?
Note: generator has his output impedance (50...600 Ohms). You have to
consider it.

--
Gianluca

[Wecan do it]

"LAB" > wrote in message
...
> >> Then adjust the pot so that the voltage drops to half
> what you measured with no resistance in the circuit. Then
> measure the resistance of the
> pot. That's half the input impedance.
>
> If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen
> Rin=Rpot. Why the half?


Because if it is half then you can read Zin directly from the
pot with your multimeter.


peace
dawg

[Geoff]

Mike Rivers wrote:
> David Aguilera wrote:
>
>> I'm just getting into the electrical side of this field and am really
>> curious as to how to go about building the shunt resistor. If you
>> have the time to enlighten me I would greatly appreciate it.
>
> Make up a short (1 foot or so) mic cable with a resistor connected
> between pins 2 and 3 of the XLR connector on one end.

An XLR-M to XLR-F 'barrel' adaptor is tidier.

geoff

[Geoff]

Wecan do it wrote:
> "LAB" > wrote in message
> ...
>> >> Then adjust the pot so that the voltage drops to half
>> what you measured with no resistance in the circuit. Then
>> measure the resistance of the
>> pot. That's half the input impedance.
>>
>> If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen
>> Rin=Rpot. Why the half?
>
>
> Because if it is half then you can read Zin directly from the
> pot with your multimeter.

Not if there is a coupling capacitor in the way.

geoff

[Mike Rivers]

LAB wrote:

> If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen Rin=Rpot. Why
> the half?

Which half? When the voltage drops in half, half the voltage is dropped
across
the preamp input and the pot, so their impedances are equal. This is of
course
ignoring the source resistance of the generator, which you may not be able
to do, depending on the generator or what you do about it.

If it's the half of the impedance you're asking about, the other leg of
the differential
input has (presumably) the same impedance, and both are across the
microphone,
essentially in series.

> Note: generator has his output impedance (50...600 Ohms). You have to
> consider it.

There's always some wise guy in the audience. You're correct of course,
but I
didn't mention that in my reply for two reasons:

1 - the guy probably isn't going to make the measurement as I described
anyway
2 - He's going to ask "what's a good generator that I can buy from eBay?

I'd probably suggest that he use a DAW program to generate a sine wave
and use his sound card as a generator. If it's something fancier than the
sound card built into his computer, it will probably have a source impedance
of around 20 ohms.

Alternately, he can build an attenuator which he may need anyway to get the
generator output low enough not to clip the preamp, and make the shunt
resistor
low enough so the generator source impedance is insignificant.

[Mike Rivers]

geoff wrote:

> An XLR-M to XLR-F 'barrel' adaptor is tidier.

But you'd have to buy it. You can make a short cable out of
a long cable, even one that you've junked because it's faulty,
as long as you don't use the faulty part.

[PStamler]

On Nov 9, 6:15*pm, Mike Rivers > wrote:
> geoff wrote:
> > An XLR-M to XLR-F 'barrel' adaptor is tidier.
>
> But you'd have to buy it. You can make a short cable out of
> a long cable, even one that you've junked because it's faulty,
> as long as you don't use the faulty part.

As the guy who started some of this discussion with an article called
"The Taming of the Shure" in Recording Magazine, let me weigh in with
a couple of suggestions.

1. I don't recommend using barrel connectors; if you put them on the
preamp/mixer end of the cable, one yank of the cable can badly torque
the XLR on the mixer/preamp, possibly causing expensive damage. A
short cable is safer.

2. Solder the resistor between pins 2 and 3 of the male connector on
the cable. I recommend the male connector because there's a bit more
room inside the shell. Even so, you'll need to snip the leads off real
short. Make sure that, when you solder in the resistor, the cable
doesn't come unsoldered. This is a lot easier to do properly with a
Neutrik connector rather than Switchcraft.

3. If you look at your mixer/preamp's manual, you should find the
input impedance listed and can compute the proper parallel resistor.
In the absence of more data, though, for an SM57 a 681 ohm (NOT 681k!)
resistor will usually give good results.

4. The improvement is mostly in the area of cleanness and clarity, and
lack of high-frequency "hashiness". In the comparison I originally
did, we listened to the SM57 on a drumkit; with a standard load (2k)
the cymbals sounded more like white noise than the metallic ring a
cymbal should have. With the parallel resistor, it sounded much more
like a real cymbal. On acoustic guitar switching to the parallel
resistor channel took away a lot of the "ringy" quality at high
frequencies.

5. I've only found a few microphones that are helped by this
technique; the most important was the SM57 family (SM56 and SM58
included). The AKG D112 got a lot less "pillowy" and a lot tighter on
the bottom, but the jury's out whether that was an improvement. Among
the mics for which this makes little or no difference are Electro-
Voice RE15 and RE20 and Shure Beta57 It's not recommended for
condenser mics.

Peace,
Paul

[Geoff]

Mike Rivers wrote:
> geoff wrote:
>
>> An XLR-M to XLR-F 'barrel' adaptor is tidier.
>
> But you'd have to buy it. You can make a short cable out of
> a long cable, even one that you've junked because it's faulty,
> as long as you don't use the faulty part.

Then you need to have (or buy) an XLR-M and XLR-F which you can now only use
for that purpose.

Whatever works for you. I have a labelled set of 6 of the aforementioned
barrel adaptors, and another pair wired as polarity changers. For a few
bucks each (unless one is addicted to Neutrik) it's really neither here nor
there....


geoff

[Geoff]

PStamler wrote:
> On Nov 9, 6:15 pm, Mike Rivers > wrote:
>> geoff wrote:
>>> An XLR-M to XLR-F 'barrel' adaptor is tidier.
>>
>> But you'd have to buy it. You can make a short cable out of
>> a long cable, even one that you've junked because it's faulty,
>> as long as you don't use the faulty part.
>
> As the guy who started some of this discussion with an article called
> "The Taming of the Shure" in Recording Magazine, let me weigh in with
> a couple of suggestions.
>
> 1. I don't recommend using barrel connectors; if you put them on the
> preamp/mixer end of the cable, one yank of the cable can badly torque
> the XLR on the mixer/preamp, possibly causing expensive damage. A
> short cable is safer.

Just like any mic XLR that is plugged in then, but admittedly a little more
so because of the fulcrum/leverage/thing. But as I routinely gaffer the
attached cables to something solid, have never had a problem.

>
> 4. The improvement is mostly in the area of cleanness and clarity, and
> lack of high-frequency "hashiness". In the comparison I originally
> did, we listened to the SM57 on a drumkit; with a standard load (2k)
> the cymbals sounded more like white noise than the metallic ring a
> cymbal should have. With the parallel resistor, it sounded much more
> like a real cymbal. On acoustic guitar switching to the parallel
> resistor channel took away a lot of the "ringy" quality at high
> frequencies.

I find it takes the harsh splashiness off the 57s, and makes the bottom end
firmer. Nothing like a nice firm bottom. With the loader, 57s more usable
on toms.

geoff

[David Gravereaux]

This is just Thévenin's Equivalent. Write it out.

If you want a 600 ohm load, solve for Z as the shunt knowing Zpre:

600 = 1/((1/Zpre)+(1/Z))
or
Z = 1/(0.001667 + 1/Zpre)
--



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[Mike Rivers]

geoff wrote:

> Then you need to have (or buy) an XLR-M and XLR-F which you can now only use
> for that purpose.

No you don't. Everybody has a useless mic cable lying around somewhere.
That contains
all the parts you need except for the resistor, and you'd have to buy
that anyway. I fully
agree with Paul's example of too much torque on the chassis connector,
It would probably
be OK to put a barrel adapter on the mic end if the mic stayed on a
stand and you secured the
cable. But he was talking about improved sound on cymbals, which
suggests drum overheads,
which suggests high, which probably doesn't need to be any higher.

> Whatever works for you.

That works for me.

[LAB]

> Then adjust the pot so that the voltage drops to half what you measured
> with no resistance in the circuit. Then measure the resistance of
the pot. *That's half the input impedance*.

If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen Rin=Rpot. Why *the
half*?
Note: generator has his output impedance (50...600 Ohms). You have to
consider it.

>> Because if it is half then you can read Zin directly from the pot with
>> your multimeter.

>>> Not if there is a coupling capacitor in the way.

I was assuming a balanced 1kHz signal...
You could measure -6dB by a VUmeter on the preamp/mixer out.

--
Gianluca

[Ian Bell[_2_]]

PStamler wrote:
> On Nov 9, 6:15 pm, Mike Rivers > wrote:
>> geoff wrote:
>>> An XLR-M to XLR-F 'barrel' adaptor is tidier.
>> But you'd have to buy it. You can make a short cable out of
>> a long cable, even one that you've junked because it's faulty,
>> as long as you don't use the faulty part.
>
> As the guy who started some of this discussion with an article called
> "The Taming of the Shure" in Recording Magazine, let me weigh in with
> a couple of suggestions.
>
> 1. I don't recommend using barrel connectors; if you put them on the
> preamp/mixer end of the cable, one yank of the cable can badly torque
> the XLR on the mixer/preamp, possibly causing expensive damage. A
> short cable is safer.
>
> 2. Solder the resistor between pins 2 and 3 of the male connector on
> the cable. I recommend the male connector because there's a bit more
> room inside the shell. Even so, you'll need to snip the leads off real
> short. Make sure that, when you solder in the resistor, the cable
> doesn't come unsoldered. This is a lot easier to do properly with a
> Neutrik connector rather than Switchcraft.
>
> 3. If you look at your mixer/preamp's manual, you should find the
> input impedance listed and can compute the proper parallel resistor.
> In the absence of more data, though, for an SM57 a 681 ohm (NOT 681k!)
> resistor will usually give good results.
>
> 4. The improvement is mostly in the area of cleanness and clarity, and
> lack of high-frequency "hashiness". In the comparison I originally
> did, we listened to the SM57 on a drumkit; with a standard load (2k)


Since when has a 'standard' load been 2K??


> the cymbals sounded more like white noise than the metallic ring a
> cymbal should have. With the parallel resistor, it sounded much more
> like a real cymbal. On acoustic guitar switching to the parallel
> resistor channel took away a lot of the "ringy" quality at high
> frequencies.
>

Dynamic mics are basically inductive which means their impedance rises
with frequency. By loading it with 680R instead of 2K you effectively
hit the high frequency response - something you can do with infinitely
more precision using EQ.

Cheers

Ian


> 5. I've only found a few microphones that are helped by this
> technique; the most important was the SM57 family (SM56 and SM58
> included). The AKG D112 got a lot less "pillowy" and a lot tighter on
> the bottom, but the jury's out whether that was an improvement. Among
> the mics for which this makes little or no difference are Electro-
> Voice RE15 and RE20 and Shure Beta57 It's not recommended for
> condenser mics.
>
> Peace,
> Paul

[Don Pearce[_3_]]

On Tue, 10 Nov 2009 15:28:36 +0000, Ian Bell >
wrote:

>Dynamic mics are basically inductive which means their impedance rises
>with frequency. By loading it with 680R instead of 2K you effectively
>hit the high frequency response - something you can do with infinitely
>more precision using EQ.
>
>Cheers
>
>Ian

You also change the Q of the resonances, not quite so simple with EQ.

d

[Scott Dorsey]

Ian Bell > wrote:
>
>Since when has a 'standard' load been 2K??

Since cheap consoles with transformerless input stages became standard.
It's depressing.

>Dynamic mics are basically inductive which means their impedance rises
>with frequency. By loading it with 680R instead of 2K you effectively
>hit the high frequency response - something you can do with infinitely
>more precision using EQ.

That's not all that is going on here. You're adjusting the mechanical
damping of the diaphragm, and moving the resonance down and widening it,
as you put electrical (and thus mechanical) load on. Many dynamic elements
will ring badly if they are insufficiently loaded.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers]

Ian Bell wrote:

> Since when has a 'standard' load been 2K??

It's sort of a roughly weighted average of the input impedance of
a good many modern transformerless preamps and mixing consoles.
This is typical of the gear to which an SM57 is likely to be connected,
at least among the Recording Magazine readership, where Paul's
article was published.

Perhaps "typical" would have been a better term, unless (and I don't
recall the details of the study) a specific load resistor for each preamp
was chosen so that the mic would be loaded by 2K for any preamp
in the study. This would allow the preamp to be the major source of
differences in sound when used with an SM57.

Further listening experiments indicated that the mic sounded better
when loaded with 600 ohms (adjusted for the preamp used for testing).

> Dynamic mics are basically inductive which means their impedance rises
> with frequency. By loading it with 680R instead of 2K you effectively
> hit the high frequency response - something you can do with infinitely
> more precision using EQ.

More important, you change the damping of the diaphragm assembly,
which broadens resonant peaks and may even change the frequency
of some resonances. That's not easily done with EQ.

[Wecan do it]

"LAB" > wrote in message
...

> If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen
> Rin=Rpot. Why *the > half*?

>>> Because if it is half then you can read Zin directly from
>>> the pot with your multimeter.

>>>> Not if there is a coupling capacitor in the way.


True but not applicable.

If you ever measured impedance using the voltage divider
method you would know the pot is outside of the device under
test ( the preamp whos impedance you are measuring) and once
you adjust the pot for half Vgen you remove the pot from the
circuit and measure it with your multimeter.

The pot (or more correctly a rheostat in the properly wired
configuration) will be equal to the input impedance at the
frequency Vgen is set at. It is impossible for a coupling
capacitor to be in the way without you knowing it.

If I was to measure the impedance I would do the same voltage
devider method but use my FFT analyzer to graph the impedance
at a few thousand frequencies to be sure nothing funny is
going on.

peace
dawg

[Ian Bell[_2_]]

Don Pearce wrote:
> On Tue, 10 Nov 2009 15:28:36 +0000, Ian Bell >
> wrote:
>
>> Dynamic mics are basically inductive which means their impedance rises
>> with frequency. By loading it with 680R instead of 2K you effectively
>> hit the high frequency response - something you can do with infinitely
>> more precision using EQ.
>>
>> Cheers
>>
>> Ian
>
> You also change the Q of the resonances, not quite so simple with EQ.
>
> d

I suspect the Q is so low in most mics it makes no difference.

Cheers

Ian

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Since when has a 'standard' load been 2K??
>
> Since cheap consoles with transformerless input stages became standard.
> It's depressing.
>
>> Dynamic mics are basically inductive which means their impedance rises
>> with frequency. By loading it with 680R instead of 2K you effectively
>> hit the high frequency response - something you can do with infinitely
>> more precision using EQ.
>
> That's not all that is going on here. You're adjusting the mechanical
> damping of the diaphragm, and moving the resonance down and widening it,
> as you put electrical (and thus mechanical) load on. Many dynamic elements
> will ring badly if they are insufficiently loaded.
> --scott
>

Personally I doubt that is a factor. The Q of the average dynamic mic is
so low that changing the load this way will make little difference.

Cheers

ian

[Ian Bell[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> Since when has a 'standard' load been 2K??
>
> It's sort of a roughly weighted average of the input impedance of
> a good many modern transformerless preamps and mixing consoles.
> This is typical of the gear to which an SM57 is likely to be connected,
> at least among the Recording Magazine readership, where Paul's
> article was published.
>
> Perhaps "typical" would have been a better term, unless (and I don't
> recall the details of the study) a specific load resistor for each preamp
> was chosen so that the mic would be loaded by 2K for any preamp
> in the study. This would allow the preamp to be the major source of
> differences in sound when used with an SM57.
>
> Further listening experiments indicated that the mic sounded better
> when loaded with 600 ohms (adjusted for the preamp used for testing).
>
>> Dynamic mics are basically inductive which means their impedance rises
>> with frequency. By loading it with 680R instead of 2K you effectively
>> hit the high frequency response - something you can do with infinitely
>> more precision using EQ.
>
> More important, you change the damping of the diaphragm assembly,
> which broadens resonant peaks and may even change the frequency
> of some resonances. That's not easily done with EQ.
>


Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
mic is so low that this is not a factor.


Cheers

ian

[Scott Dorsey]

Ian Bell > wrote:
>Scott Dorsey wrote:
>> Ian Bell > wrote:
>>> Since when has a 'standard' load been 2K??
>>
>> Since cheap consoles with transformerless input stages became standard.
>> It's depressing.
>>
>>> Dynamic mics are basically inductive which means their impedance rises
>>> with frequency. By loading it with 680R instead of 2K you effectively
>>> hit the high frequency response - something you can do with infinitely
>>> more precision using EQ.
>>
>> That's not all that is going on here. You're adjusting the mechanical
>> damping of the diaphragm, and moving the resonance down and widening it,
>> as you put electrical (and thus mechanical) load on. Many dynamic elements
>> will ring badly if they are insufficiently loaded.
>
>Personally I doubt that is a factor. The Q of the average dynamic mic is
>so low that changing the load this way will make little difference.

You'd be shocked. Take an SM-57 and look at an impulse with a 600 ohm
load and with an unterminated output. It's not a subtle difference.
You'd think the losses through the internal transformer would reduce the
effects of loading changes, but they are still very significant.

On an RE-20 you won't notice it so much, mind you. Maybe not at all.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Geoff]

Ian Bell wrote:

>>
>
> Personally I doubt that is a factor. The Q of the average dynamic mic
> is so low that changing the load this way will make little difference.
>

Given the easily-heard results with a humble SM57, a simple change in
loading clearly does make a difference.

If you are skeptical, try it !

geoff

[Geoff]

Wecan do it wrote:
> "LAB" > wrote in message
> ...
>
>> If Vgen=Vpot+Vin, when Vin is the half (-6dB) of Vgen
>> Rin=Rpot. Why *the > half*?
>
>>>> Because if it is half then you can read Zin directly from
>>>> the pot with your multimeter.
>
>>>>> Not if there is a coupling capacitor in the way.
>
>
> True but not applicable.


Thought you were advocating testing in input impedence of a preamp by
hooking a multimeter to it and simply reading the R of the scale..

geoff

[Mike Rivers]

geoff wrote:

> Thought you were advocating testing in input impedence of a preamp by
> hooking a multimeter to it and simply reading the R of the scale..

I think that's what the original poster was dreaming about, but he's
been told
that he can't. But he can still make use of his multimeter to make the
measurement.
It just takes some extra stuff.

[Mike Rivers]

Ian Bell wrote:

> I suspect the Q is so low in most mics it makes no difference.

Suspect all you want, but test it before you poo-poo the concept.

[Mike Rivers]

Ian Bell wrote:

> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
> mic is so low that this is not a factor.

We're not talking about an "average dynamic mic" here (whatever that
is), we're
talking about a specific mic, an SM57. Given the large market
penetration, it
may be the most popular mic in its class. That might make it "average"
in some
circles.

As Scott pointed out, an RE20 doesn't exhibit the same resonant
characteristics
as an SM57. and doesn't have the same problem. A loading experiment with an
RE20 probably wouldn't yield much useful data.

[Mark]

On Nov 10, 12:21*pm, Ian Bell > wrote:
> Mike Rivers wrote:
> > Ian Bell wrote:
>
> >> Since when has a 'standard' load been 2K??
>
> > It's sort of a roughly weighted average of the input impedance of
> > a good many modern transformerless preamps and mixing consoles.
> > This is typical of the gear to which an SM57 is likely to be connected,
> > at least among the Recording Magazine readership, where Paul's
> > article was published.
>
> > Perhaps "typical" would have been a better term, unless (and I don't
> > recall the details of the study) a specific load resistor for each preamp
> > was chosen so that the mic would be loaded by 2K for any preamp
> > in the study. This would allow the preamp to be the major source of
> > differences in sound when used with an SM57.
>
> > Further listening experiments indicated that the mic sounded better
> > when loaded with 600 ohms (adjusted for the preamp used for testing).
>
> >> Dynamic mics are basically inductive which means their impedance rises
> >> with frequency. By loading it with 680R instead of 2K you effectively
> >> hit the high frequency response - something you can do with infinitely
> >> more precision using EQ.
>
> > More important, you change the damping of the diaphragm assembly,
> > which broadens resonant peaks and may even change the frequency
> > of some resonances. That's not easily done with EQ.
>
> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
> mic is so low that this is not a factor.
>
> Cheers
>
> ian- Hide quoted text -
>
> - Show quoted text -

Ian,

you don't want to let facts and science get in the way of
mythology :-)

Mark

[Scott Dorsey]

Mike Rivers > wrote:
>
>As Scott pointed out, an RE20 doesn't exhibit the same resonant
>characteristics
>as an SM57. and doesn't have the same problem. A loading experiment with an
>RE20 probably wouldn't yield much useful data.

My guess is that the coupling in the RE-20 just is a lot lower, so load
changes have less effect on the mechanical behaviour of the system.
If that were the case, you'd expect the output of the RE-20 to also be
a lot lower, which it is.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[PStamler]

On Nov 10, 11:21*am, Ian Bell > wrote:
> Mike Rivers wrote:
> > Ian Bell wrote:
>
> >> Since when has a 'standard' load been 2K??
>
> > It's sort of a roughly weighted average of the input impedance of
> > a good many modern transformerless preamps and mixing consoles.
> > This is typical of the gear to which an SM57 is likely to be connected,
> > at least among the Recording Magazine readership, where Paul's
> > article was published.
>
> > Perhaps "typical" would have been a better term, unless (and I don't
> > recall the details of the study) a specific load resistor for each preamp
> > was chosen so that the mic would be loaded by 2K for any preamp
> > in the study. This would allow the preamp to be the major source of
> > differences in sound when used with an SM57.
>
> > Further listening experiments indicated that the mic sounded better
> > when loaded with 600 ohms (adjusted for the preamp used for testing).
>
> >> Dynamic mics are basically inductive which means their impedance rises
> >> with frequency. By loading it with 680R instead of 2K you effectively
> >> hit the high frequency response - something you can do with infinitely
> >> more precision using EQ.
>
> > More important, you change the damping of the diaphragm assembly,
> > which broadens resonant peaks and may even change the frequency
> > of some resonances. That's not easily done with EQ.
>
> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
> mic is so low that this is not a factor.

Which perhaps is why the change in loading had little or no effect on
most of the microphones we tried -- Sennheisers, E-Vs, Shure Beta
series, etc.. But the SM57 family was designed in a different era, and
the designers clearly relied on electrical damping more than
mechanical damping, on the assumption of a lower preamp input
impedance than is used nowadays.

As Scott noted, this is not only about the flattening of resonance
curves; it's also about the damping of the motor, and it manifests
itself as cleaner sound.

Peace,
Paul

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Since when has a 'standard' load been 2K??
>>> Since cheap consoles with transformerless input stages became standard.
>>> It's depressing.
>>>
>>>> Dynamic mics are basically inductive which means their impedance rises
>>>> with frequency. By loading it with 680R instead of 2K you effectively
>>>> hit the high frequency response - something you can do with infinitely
>>>> more precision using EQ.
>>> That's not all that is going on here. You're adjusting the mechanical
>>> damping of the diaphragm, and moving the resonance down and widening it,
>>> as you put electrical (and thus mechanical) load on. Many dynamic elements
>>> will ring badly if they are insufficiently loaded.
>> Personally I doubt that is a factor. The Q of the average dynamic mic is
>> so low that changing the load this way will make little difference.
>
> You'd be shocked. Take an SM-57 and look at an impulse with a 600 ohm
> load and with an unterminated output. It's not a subtle difference.
> You'd think the losses through the internal transformer would reduce the
> effects of loading changes, but they are still very significant.
>
> On an RE-20 you won't notice it so much, mind you. Maybe not at all.
> --scott
>

Yes but we are not talking about the difference between unloaded and
loaded but between a 2K load and a 680R load. In both case I bet the Q
is below 1.

Cheers

Ian

[Ian Bell[_2_]]

geoff wrote:
> Ian Bell wrote:
>
>> Personally I doubt that is a factor. The Q of the average dynamic mic
>> is so low that changing the load this way will make little difference.
>>
>
> Given the easily-heard results with a humble SM57, a simple change in
> loading clearly does make a difference.
>
> If you are skeptical, try it !
>
> geoff
>
>

You miss the point. I am suggesting that loading does nothing that EQ
will not achieve and with greater flexibility.

Cheers

Ian

[Ian Bell[_2_]]

Mark wrote:
> On Nov 10, 12:21 pm, Ian Bell > wrote:
>> Mike Rivers wrote:
>>> Ian Bell wrote:
>>>> Since when has a 'standard' load been 2K??
>>> It's sort of a roughly weighted average of the input impedance of
>>> a good many modern transformerless preamps and mixing consoles.
>>> This is typical of the gear to which an SM57 is likely to be connected,
>>> at least among the Recording Magazine readership, where Paul's
>>> article was published.
>>> Perhaps "typical" would have been a better term, unless (and I don't
>>> recall the details of the study) a specific load resistor for each preamp
>>> was chosen so that the mic would be loaded by 2K for any preamp
>>> in the study. This would allow the preamp to be the major source of
>>> differences in sound when used with an SM57.
>>> Further listening experiments indicated that the mic sounded better
>>> when loaded with 600 ohms (adjusted for the preamp used for testing).
>>>> Dynamic mics are basically inductive which means their impedance rises
>>>> with frequency. By loading it with 680R instead of 2K you effectively
>>>> hit the high frequency response - something you can do with infinitely
>>>> more precision using EQ.
>>> More important, you change the damping of the diaphragm assembly,
>>> which broadens resonant peaks and may even change the frequency
>>> of some resonances. That's not easily done with EQ.
>> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
>> mic is so low that this is not a factor.
>>
>> Cheers
>>
>> ian- Hide quoted text -
>>
>> - Show quoted text -
>
> Ian,
>
> you don't want to let facts and science get in the way of
> mythology :-)
>
> Mark

We are not disputing facts i.e that loading changes the response of an
SM57 - we are discussing the mechanism that causes it.


Cheers

Ian

[Ian Bell[_2_]]

PStamler wrote:
> On Nov 10, 11:21 am, Ian Bell > wrote:
>> Mike Rivers wrote:
>>> Ian Bell wrote:
>>>> Since when has a 'standard' load been 2K??
>>> It's sort of a roughly weighted average of the input impedance of
>>> a good many modern transformerless preamps and mixing consoles.
>>> This is typical of the gear to which an SM57 is likely to be connected,
>>> at least among the Recording Magazine readership, where Paul's
>>> article was published.
>>> Perhaps "typical" would have been a better term, unless (and I don't
>>> recall the details of the study) a specific load resistor for each preamp
>>> was chosen so that the mic would be loaded by 2K for any preamp
>>> in the study. This would allow the preamp to be the major source of
>>> differences in sound when used with an SM57.
>>> Further listening experiments indicated that the mic sounded better
>>> when loaded with 600 ohms (adjusted for the preamp used for testing).
>>>> Dynamic mics are basically inductive which means their impedance rises
>>>> with frequency. By loading it with 680R instead of 2K you effectively
>>>> hit the high frequency response - something you can do with infinitely
>>>> more precision using EQ.
>>> More important, you change the damping of the diaphragm assembly,
>>> which broadens resonant peaks and may even change the frequency
>>> of some resonances. That's not easily done with EQ.
>> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
>> mic is so low that this is not a factor.
>
> Which perhaps is why the change in loading had little or no effect on
> most of the microphones we tried -- Sennheisers, E-Vs, Shure Beta
> series, etc.. But the SM57 family was designed in a different era, and
> the designers clearly relied on electrical damping more than
> mechanical damping, on the assumption of a lower preamp input
> impedance than is used nowadays.

No, now you are assuming damping is the mechanism and there is no
evidence of that yet.

>
> As Scott noted, this is not only about the flattening of resonance
> curves; it's also about the damping of the motor, and it manifests
> itself as cleaner sound.

No, he suggests it may be, no one has done any tests to show if this is
the case.


Cheers

Ian
>
> Peace,
> Paul

[Ian Bell[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> I suspect the Q is so low in most mics it makes no difference.
>
> Suspect all you want, but test it before you poo-poo the concept.

Agreed, but no one has made any measurements at all. All we have to go
on so far are some subjective listening tests which show that it sound
'different'. They tell you nothing about why. However, I do know the
inductance of tape replay heads is much higher than that of dynamic mics
and tape heads resonate in the over 20KHz region so it is reasonable to
suppose dynamic mics will have a resonance much higher than this. Damped
with 2K or 680R they will not affect the response in the audio band.
The simple rise of impedance with frequency due to the inductance of the
mic does explain what is 'heard' and this could equally be achieved with EQ.

Cheers

Ian

[Geoff]

Ian Bell wrote:
> geoff wrote:
>> Ian Bell wrote:
>>
>>> Personally I doubt that is a factor. The Q of the average dynamic
>>> mic is so low that changing the load this way will make little
>>> difference.
>>
>> Given the easily-heard results with a humble SM57, a simple change in
>> loading clearly does make a difference.
>>
>> If you are skeptical, try it !
>>
>> geoff
>>
>>
>
> You miss the point. I am suggesting that loading does nothing that EQ
> will not achieve and with greater flexibility.

And we are suggesting that it indeed does. Damping of the diaphram that has
an audible ( and beneficiary) effect on the unwanted results physical
excitation of the diaphram.

geoff

[Scott Dorsey]

Ian Bell > wrote:
>
>Yes but we are not talking about the difference between unloaded and
>loaded but between a 2K load and a 680R load. In both case I bet the Q
>is below 1.

Didn't measure it directly, but I sure saw a difference in ringing on
a scope. If you want to measure it, I'd be curious what you come up with.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>
>You miss the point. I am suggesting that loading does nothing that EQ
>will not achieve and with greater flexibility.

EQ doesn't stop ringing. It's not the right tool for that. It can change
ringing, mind you.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>Agreed, but no one has made any measurements at all. All we have to go
>on so far are some subjective listening tests which show that it sound
>'different'. They tell you nothing about why. However, I do know the
>inductance of tape replay heads is much higher than that of dynamic mics
>and tape heads resonate in the over 20KHz region so it is reasonable to
>suppose dynamic mics will have a resonance much higher than this.

Not at all. You're missing the point, this is a MECHANICAL resonance.
It's being mechanically altered by the mechanical load of the coil in
the magnetic field, which is what is changing the MECHANICAL damping of
the system. It's not like a simple coil at all.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mark]

On Nov 10, 7:24*pm, (Scott Dorsey) wrote:
> Ian Bell > wrote:
>
> >Agreed, but no one has made any measurements at all. All we have to go
> >on so far are some subjective listening tests which show that it sound
> >'different'. They tell you nothing about why. However, I do know the
> >inductance of tape replay heads is much higher than that of dynamic mics
> >and tape heads resonate in the over 20KHz region so it is reasonable to
> >suppose dynamic mics will have a resonance much higher than this.
>
> Not at all. *You're missing the point, this is a MECHANICAL resonance.
> It's being mechanically altered by the mechanical load of the coil in
> the magnetic field, which is what is changing the MECHANICAL damping of
> the system. *It's not like a simple coil at all.
> --scott
>
> --
> "C'est un Nagra. *C'est suisse, et tres, tres precis."

Ian,

I agree with you..

there are audible effects of load changes but they are electrical in
nature as discussed here:

http://www.jensen-transformers.com/an/an005.pdf

and I also agree with you that these audible effects have little to do
with mechanical resonances in the mic but rather have everything to do
with electrical loading effects and that these electrical effects can
be well approximated with standard EQ.

A lightly loaded SM57 with a piece of cable creates an ELECTRICAL
resonance as discussed in the paper above that creates high end
peaking. A lower load resistance can damp this ELECTRICAL resonance
and make the mic sound "warmer" just the same as EQ can.

The mechanical resonances in the mic are lightly coupled to the
electrical load so changes in the electrical load have almost no
effect on the MECHANICAL resonances.

Just to be clear, Ian, I agree with you.

Mark

[hank alrich]

Ian Bell > wrote:

> geoff wrote:
> > Ian Bell wrote:
> >
> >> Personally I doubt that is a factor. The Q of the average dynamic mic
> >> is so low that changing the load this way will make little difference.
> >>
> >
> > Given the easily-heard results with a humble SM57, a simple change in
> > loading clearly does make a difference.
> >
> > If you are skeptical, try it !
> >
> > geoff
> >
> >
>
> You miss the point. I am suggesting that loading does nothing that EQ
> will not achieve and with greater flexibility.
>
> Cheers
>
> Ian

But it does, and that is the point of suggesting you TRY it.

You assume this and that - so much for empirical empirical.

--
ha
shut up and play your guitar

[hank alrich]

Ian Bell > wrote:

> Mike Rivers wrote:
> > Ian Bell wrote:
> >
> >> Since when has a 'standard' load been 2K??
> >
> > It's sort of a roughly weighted average of the input impedance of
> > a good many modern transformerless preamps and mixing consoles.
> > This is typical of the gear to which an SM57 is likely to be connected,
> > at least among the Recording Magazine readership, where Paul's
> > article was published.
> >
> > Perhaps "typical" would have been a better term, unless (and I don't
> > recall the details of the study) a specific load resistor for each preamp
> > was chosen so that the mic would be loaded by 2K for any preamp
> > in the study. This would allow the preamp to be the major source of
> > differences in sound when used with an SM57.
> >
> > Further listening experiments indicated that the mic sounded better
> > when loaded with 600 ohms (adjusted for the preamp used for testing).
> >
> >> Dynamic mics are basically inductive which means their impedance rises
> >> with frequency. By loading it with 680R instead of 2K you effectively
> >> hit the high frequency response - something you can do with infinitely
> >> more precision using EQ.
> >
> > More important, you change the damping of the diaphragm assembly,
> > which broadens resonant peaks and may even change the frequency
> > of some resonances. That's not easily done with EQ.
> >
>
>
> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
> mic is so low that this is not a factor.
>
>
> Cheers
>
> ian

Suspect in one hand and **** in the other. Which one fills up first?

--
ha
shut up and play your guitar

[PStamler]

And, just to be clear, the two channels had input impedances of 2k and
500 ohms, respectively. The 681 ohm resistor in parallel with a
typical tranformerless-preamp impedance of 1800-2200 gives about 500
ohms, which is why I suggested it as a first try.

As Scott says, we're dealing here with a mechanical resonance, NOT an
electrical resonance.

Mr. Bell should try the experiment before belittling it further. It
won't cost much; heck, he could add the resistor to a mic cable he
isn't using, and snip it out afterwards.

One thing that's important, though, is to match levels very carefully.
After setting the level on channel 1, we put the mic in front of a
guitar amplifier that had a 700Hz tone running through it. We used
that to match the levels of the two preamp channels (with their
different input Zs) to within a pointer-width on a standard VU meter,
or about 0.1dB. If you don't do the match that closely, the test is
meaningless.

Our two test instruments were a stripped-down drumkit (snare, cymbal
and kick) and an acoustic guitar, played with fingerpicks in a
percussive blues style (gentle bare-finger picking didn't tell us
squat). The difference was most audible on cymbal and guitar.

Peace,
Paul

[Ian Bell[_2_]]

geoff wrote:
> Ian Bell wrote:
>> geoff wrote:
>>> Ian Bell wrote:
>>>
>>>> Personally I doubt that is a factor. The Q of the average dynamic
>>>> mic is so low that changing the load this way will make little
>>>> difference.
>>> Given the easily-heard results with a humble SM57, a simple change in
>>> loading clearly does make a difference.
>>>
>>> If you are skeptical, try it !
>>>
>>> geoff
>>>
>>>
>> You miss the point. I am suggesting that loading does nothing that EQ
>> will not achieve and with greater flexibility.
>
> And we are suggesting that it indeed does. Damping of the diaphram that has
> an audible ( and beneficiary) effect on the unwanted results physical
> excitation of the diaphram.
>
> geoff
>
>

No, all you said was changing the loading makes a difference. I am not
disputing that.

Cheers

Ian

[Ian Bell[_2_]]

hank alrich wrote:
> Ian Bell > wrote:
>
>> geoff wrote:
>>> Ian Bell wrote:
>>>
>>>> Personally I doubt that is a factor. The Q of the average dynamic mic
>>>> is so low that changing the load this way will make little difference.
>>>>
>>> Given the easily-heard results with a humble SM57, a simple change in
>>> loading clearly does make a difference.
>>>
>>> If you are skeptical, try it !
>>>
>>> geoff
>>>
>>>
>> You miss the point. I am suggesting that loading does nothing that EQ
>> will not achieve and with greater flexibility.
>>
>> Cheers
>>
>> Ian
>
> But it does, and that is the point of suggesting you TRY it.


There is no evidence it does. All we have so far is subjective
statements. No one has made any measurements.

Cheers

Ian
>
> You assume this and that - so much for empirical empirical.
>

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Agreed, but no one has made any measurements at all. All we have to go
>> on so far are some subjective listening tests which show that it sound
>> 'different'. They tell you nothing about why. However, I do know the
>> inductance of tape replay heads is much higher than that of dynamic mics
>> and tape heads resonate in the over 20KHz region so it is reasonable to
>> suppose dynamic mics will have a resonance much higher than this.
>
> Not at all. You're missing the point, this is a MECHANICAL resonance.
> It's being mechanically altered by the mechanical load of the coil in
> the magnetic field, which is what is changing the MECHANICAL damping of
> the system. It's not like a simple coil at all.
> --scott
>


Well, if you want to throw mechanical resonances into the pot as well
that's fine by me. However, dynamic mic manufacturers aim to get the
main resonance as low as possible because the response drops like a
stone below it - they aim for as much of the response as possible to be
above resonance. Looking at the SM57 frequency response it clearly
drops off steeply below 200Hz so my guess it that is where the main
resonance is.



The response rises from 3KHz to 6KHz which looks to me like it is
proportional to rate of change of flux, then falls off rapidly due to
mechanical losses (mainly stiffness).

The only way this issues will be resolved is if someone cares to make
some measurements. Until then it is all speculation.

Cheers

Ian

[Ian Bell[_2_]]

Mark wrote:
> On Nov 10, 7:24 pm, (Scott Dorsey) wrote:
>> Ian Bell > wrote:
>>
>>> Agreed, but no one has made any measurements at all. All we have to go
>>> on so far are some subjective listening tests which show that it sound
>>> 'different'. They tell you nothing about why. However, I do know the
>>> inductance of tape replay heads is much higher than that of dynamic mics
>>> and tape heads resonate in the over 20KHz region so it is reasonable to
>>> suppose dynamic mics will have a resonance much higher than this.
>> Not at all. You're missing the point, this is a MECHANICAL resonance.
>> It's being mechanically altered by the mechanical load of the coil in
>> the magnetic field, which is what is changing the MECHANICAL damping of
>> the system. It's not like a simple coil at all.
>> --scott
>>
>> --
>> "C'est un Nagra. C'est suisse, et tres, tres precis."
>
> Ian,
>
> I agree with you..
>
> there are audible effects of load changes but they are electrical in
> nature as discussed here:
>
> http://www.jensen-transformers.com/an/an005.pdf
>
> and I also agree with you that these audible effects have little to do
> with mechanical resonances in the mic but rather have everything to do
> with electrical loading effects and that these electrical effects can
> be well approximated with standard EQ.
>
> A lightly loaded SM57 with a piece of cable creates an ELECTRICAL
> resonance as discussed in the paper above that creates high end
> peaking. A lower load resistance can damp this ELECTRICAL resonance
> and make the mic sound "warmer" just the same as EQ can.
>
> The mechanical resonances in the mic are lightly coupled to the
> electrical load so changes in the electrical load have almost no
> effect on the MECHANICAL resonances.
>
> Just to be clear, Ian, I agree with you.
>
> Mark
>
>


Thanks Mark

Cheers

Ian

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Yes but we are not talking about the difference between unloaded and
>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>> is below 1.
>
> Didn't measure it directly, but I sure saw a difference in ringing on
> a scope. If you want to measure it, I'd be curious what you come up with.
> --scott
>

So when you say 'saw a difference in ringing on the scope' what exactly
were the test conditions?

Cheers

Ian

[Ian Bell[_2_]]

hank alrich wrote:
> Ian Bell > wrote:
>
>> Mike Rivers wrote:
>>> Ian Bell wrote:
>>>
>>>> Since when has a 'standard' load been 2K??
>>> It's sort of a roughly weighted average of the input impedance of
>>> a good many modern transformerless preamps and mixing consoles.
>>> This is typical of the gear to which an SM57 is likely to be connected,
>>> at least among the Recording Magazine readership, where Paul's
>>> article was published.
>>>
>>> Perhaps "typical" would have been a better term, unless (and I don't
>>> recall the details of the study) a specific load resistor for each preamp
>>> was chosen so that the mic would be loaded by 2K for any preamp
>>> in the study. This would allow the preamp to be the major source of
>>> differences in sound when used with an SM57.
>>>
>>> Further listening experiments indicated that the mic sounded better
>>> when loaded with 600 ohms (adjusted for the preamp used for testing).
>>>
>>>> Dynamic mics are basically inductive which means their impedance rises
>>>> with frequency. By loading it with 680R instead of 2K you effectively
>>>> hit the high frequency response - something you can do with infinitely
>>>> more precision using EQ.
>>> More important, you change the damping of the diaphragm assembly,
>>> which broadens resonant peaks and may even change the frequency
>>> of some resonances. That's not easily done with EQ.
>>>
>>
>> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
>> mic is so low that this is not a factor.
>>
>>
>> Cheers
>>
>> ian
>
> Suspect in one hand and **** in the other. Which one fills up first?
>


Indeed, but until someone makes an actual measurement my **** is a good
as yours.

Cheers

Ian

[Ian Bell[_2_]]

PStamler wrote:
> And, just to be clear, the two channels had input impedances of 2k and
> 500 ohms, respectively. The 681 ohm resistor in parallel with a
> typical tranformerless-preamp impedance of 1800-2200 gives about 500
> ohms, which is why I suggested it as a first try.
>
> As Scott says, we're dealing here with a mechanical resonance, NOT an
> electrical resonance.
>
> Mr. Bell should try the experiment before belittling it further. It
> won't cost much; heck, he could add the resistor to a mic cable he
> isn't using, and snip it out afterwards.
>

I'll say it again, I do not dispute that loading an SM57 alters the way
it sounds. What we are discussion is the MECHANISM that causes that change.

> One thing that's important, though, is to match levels very carefully.
> After setting the level on channel 1, we put the mic in front of a
> guitar amplifier that had a 700Hz tone running through it. We used
> that to match the levels of the two preamp channels (with their
> different input Zs) to within a pointer-width on a standard VU meter,
> or about 0.1dB. If you don't do the match that closely, the test is
> meaningless.
>
> Our two test instruments were a stripped-down drumkit (snare, cymbal
> and kick) and an acoustic guitar, played with fingerpicks in a
> percussive blues style (gentle bare-finger picking didn't tell us
> squat). The difference was most audible on cymbal and guitar.
>

I never disagreed that there is an audible difference.

Cheers

Ian
> Peace,
> Paul

[Anahata]

On Tue, 10 Nov 2009 23:44:42 +0000, Ian Bell wrote:

> PStamler wrote:
>
>> As Scott noted, this is not only about the flattening of resonance
>> curves; it's also about the damping of the motor, and it manifests
>> itself as cleaner sound.
>
> No, he suggests it may be, no one has done any tests to show if this is
> the case.

So somebody should repeat Paul's experiment with a good EQ in the chain,
and try and determine what EQ settings are needed on an SM57 loaded with
2k to make it sound identical to the unequalised SM57 with 600 ohm load.
Or indeed, whether such a match is possible, and whether it's repeatable
if you switch the mic for another SM57.

The resonances may be narrowband, high-Q affairs that are hard to cancel
with EQ, and even if you managed it, the same EQ setting would have to be
finely adjusted for each SM57 unit it's used with. The beauty of
resistive damping, when it works, is it doesn't have to be tuned to
anything.

--
Anahata
==//== 01638 720444
http://www.treewind.co.uk ==//== http://www.myspace.com/maryanahata

[Mike Rivers]

Ian Bell wrote:

> Yes but we are not talking about the difference between unloaded and
> loaded but between a 2K load and a 680R load. In both case I bet the Q
> is below 1.

Borrow an SM57 and try it. Tell me the input impedance of the preamp you'll
be using and I'll send you a resistor. Then perhaps you can better
analyze what
you hear. Or better yet, measure it.

[Mike Rivers]

hank alrich wrote:

> But it does, and that is the point of suggesting you TRY it.
> You assume this and that - so much for empirical empirical.

Paul's conclusion was based on listening. The effect of the resistor
that Scott describes is consistent with what Paul and his students
(and others who have tried it) heard. As to whether it's correct, or
the complete explanation, could be verified by measurement. I don't
know that this has been done by anyone yet.

Ferchrissake, it's a $100 mic. It costs a lot more than that to properly
test it in a suitable acoustic test chamber. You're certainly free to
mess with EQ to try to clean up the mic, or to not use it at all if you
feel that it's too much trouble.

[Mike Rivers]

Ian Bell wrote:

> All we have so far is subjective
> statements. No one has made any measurements.

Including you. Unless you've tried "the magic load" you can't
even subjectively say that you can duplicate the results with
equalization.

I understand, though, that you like to argue and debate. We all
do, around here. We have no lives. It's what we do.

[Mike Rivers]

Ian Bell wrote:

> Agreed, but no one has made any measurements at all. All we have to go
> on so far are some subjective listening tests which show that it sound
> 'different'. They tell you nothing about why.

Perhaps this is worth a more scientific study. Or perhaps not. There are
many
things in audio that have been accepted without knowing the reason why they
work. Sometimes the scientific explanation is discovered, sometimes not.

> However, I do know the
> inductance of tape replay heads is much higher than that of dynamic mics
> and tape heads resonate in the over 20KHz region so it is reasonable to
> suppose dynamic mics will have a resonance much higher than this.

Somewhere on the shelf I have an issue of R-E-P magazine with an article by
Peter Butt in which he described a very similar experiment in which he put
shunt resistors across the playback head of a 3M M-79 recorder. He was
looking at frequency response using a flux loop and found a resistor value
that flattened out the top end of the frequency response (as he measured it)
and he concluded by listening that his recorder sounded better with the
resistor
in place. He described it (perhaps incorrectly) as damping.

Sometimes we use familiar terms that aren't technically precise, but it
does help
to explain things to the layman. And most people in this field today are
laymen.

Shall we discuss "phase" now? Or "latency?" ;)

[George's Pro Sound Co.]

"Mike Rivers" > wrote in message
...
> Ian Bell wrote:
>
>> All we have so far is subjective statements. No one has made any
>> measurements.
>
> Including you. Unless you've tried "the magic load" you can't
> even subjectively say that you can duplicate the results with
> equalization.
>
> I understand, though, that you like to argue and debate. We all
> do, around here. We have no lives. It's what we do.

actuially I almost had a life, then I got married --)
I love this thread
g

[Scott Dorsey]

Mark > wrote:
>
>The mechanical resonances in the mic are lightly coupled to the
>electrical load so changes in the electrical load have almost no
>effect on the MECHANICAL resonances.

Do the measurements and see. I think you'll be shocked at what you see on
the scope. It really does ring.

While you're at it, do a swept impedance curve on the SM-57. That's an
eye-opener too.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>
>Well, if you want to throw mechanical resonances into the pot as well
>that's fine by me. However, dynamic mic manufacturers aim to get the
>main resonance as low as possible because the response drops like a
>stone below it - they aim for as much of the response as possible to be
>above resonance. Looking at the SM57 frequency response it clearly
>drops off steeply below 200Hz so my guess it that is where the main
>resonance is.

If the mike is loaded properly, yes. The response plots that you see
on the data sheet are assuming about a 600 ohm load (Shure M67 or
the like).

>The response rises from 3KHz to 6KHz which looks to me like it is
>proportional to rate of change of flux, then falls off rapidly due to
>mechanical losses (mainly stiffness).

>The only way this issues will be resolved is if someone cares to make
>some measurements. Until then it is all speculation.

I have, as I said, made some basic qualitative measurements showing
ringing. If you want to do a full impulse response, I'd love to see it.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>Scott Dorsey wrote:
>> Ian Bell > wrote:
>>> Yes but we are not talking about the difference between unloaded and
>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>> is below 1.
>>
>> Didn't measure it directly, but I sure saw a difference in ringing on
>> a scope. If you want to measure it, I'd be curious what you come up with.
>
>So when you say 'saw a difference in ringing on the scope' what exactly
>were the test conditions?

Little baby IEC chamber, tone burst source, 600 and 10K loads into
a Neff differential amp, old Tek 565 scope. Don't recall the burst
frequency but it was probably 5KC or so.

I'd use an acoustical square wave if such a thing existed, but it doesn't.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Ian Bell[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> All we have so far is subjective statements. No one has made any
>> measurements.
>
> Including you. Unless you've tried "the magic load" you can't
> even subjectively say that you can duplicate the results with
> equalization.
>
> I understand, though, that you like to argue and debate. We all
> do, around here. We have no lives. It's what we do.


I think the term 'magic load' you used sums it up. I really am not
enamoured of these simple changes that 'work magic' in a purely
subjective way. I much prefer to understand why and how the effect is
produced but that unfortunately demotes from magic to mere science.

Cheers

Ian

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Well, if you want to throw mechanical resonances into the pot as well
>> that's fine by me. However, dynamic mic manufacturers aim to get the
>> main resonance as low as possible because the response drops like a
>> stone below it - they aim for as much of the response as possible to be
>> above resonance. Looking at the SM57 frequency response it clearly
>> drops off steeply below 200Hz so my guess it that is where the main
>> resonance is.
>
> If the mike is loaded properly, yes. The response plots that you see
> on the data sheet are assuming about a 600 ohm load (Shure M67 or
> the like).


Are you certain. Looking at Shure's own data sheet all it says is:

"Rated impedance is 150Ω (310Ω actual) for connection to
microphone inputs rated low impedance"


There is no mention at all of the test cinditions under which frequency
response is measured.

>
>> The response rises from 3KHz to 6KHz which looks to me like it is
>> proportional to rate of change of flux, then falls off rapidly due to
>> mechanical losses (mainly stiffness).
>
>> The only way this issues will be resolved is if someone cares to make
>> some measurements. Until then it is all speculation.
>
> I have, as I said, made some basic qualitative measurements showing
> ringing. If you want to do a full impulse response, I'd love to see it.


And I have asked you to specify exactly how those measurements were made.


Cheers

Ian
> --scott
>

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Yes but we are not talking about the difference between unloaded and
>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>>> is below 1.
>>> Didn't measure it directly, but I sure saw a difference in ringing on
>>> a scope. If you want to measure it, I'd be curious what you come up with.
>> So when you say 'saw a difference in ringing on the scope' what exactly
>> were the test conditions?
>
> Little baby IEC chamber, tone burst source, 600 and 10K loads into
> a Neff differential amp, old Tek 565 scope. Don't recall the burst
> frequency but it was probably 5KC or so.


So this was a burst of how many cycles of 5KHz and precisely what did
you see on the scope?

CHeers

Ian
>
> I'd use an acoustical square wave if such a thing existed, but it doesn't.
> --scott

[Ian Bell[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> Yes but we are not talking about the difference between unloaded and
>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>> is below 1.
>
> Borrow an SM57 and try it. Tell me the input impedance of the preamp you'll
> be using and I'll send you a resistor. Then perhaps you can better
> analyze what
> you hear. Or better yet, measure it.


I agree, it needs to be measured. Until then no one is 'right'.

Cheers

Ian

[Scott Dorsey]

Ian Bell > wrote:
>
>I think the term 'magic load' you used sums it up. I really am not
>enamoured of these simple changes that 'work magic' in a purely
>subjective way. I much prefer to understand why and how the effect is
>produced but that unfortunately demotes from magic to mere science.

Then make the measurement.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>Scott Dorsey wrote:
>> Ian Bell > wrote:
>>> Well, if you want to throw mechanical resonances into the pot as well
>>> that's fine by me. However, dynamic mic manufacturers aim to get the
>>> main resonance as low as possible because the response drops like a
>>> stone below it - they aim for as much of the response as possible to be
>>> above resonance. Looking at the SM57 frequency response it clearly
>>> drops off steeply below 200Hz so my guess it that is where the main
>>> resonance is.
>>
>> If the mike is loaded properly, yes. The response plots that you see
>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
>> the like).
>
>Are you certain. Looking at Shure's own data sheet all it says is:
>
>"Rated impedance is 150Ω (310Ω actual) for connection to
>microphone inputs rated low impedance"
>
>There is no mention at all of the test cinditions under which frequency
>response is measured.

That's true, and that's why all the confusion has occurred over the years.
But you'd expect that the companion mike mixer that Shure sold at the
time, for instance, would be a good match for it.

"Low impedance" would be something in the 500-600 ohm region. Olsen's
book has a good description of how bridging loads on microphones work.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>Scott Dorsey wrote:
>> Ian Bell > wrote:
>>> Scott Dorsey wrote:
>>>> Ian Bell > wrote:
>>>>> Yes but we are not talking about the difference between unloaded and
>>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>>>> is below 1.
>>>> Didn't measure it directly, but I sure saw a difference in ringing on
>>>> a scope. If you want to measure it, I'd be curious what you come up with.
>>> So when you say 'saw a difference in ringing on the scope' what exactly
>>> were the test conditions?
>>
>> Little baby IEC chamber, tone burst source, 600 and 10K loads into
>> a Neff differential amp, old Tek 565 scope. Don't recall the burst
>> frequency but it was probably 5KC or so.
>
>So this was a burst of how many cycles of 5KHz and precisely what did
>you see on the scope?

Probably around a .1 second burst. What I saw on the scope was a nice
ringing on the trailing edge of the waveform, and that ringing was not at
the excitation frequency.

Again, it's been quite a few years since I did any of this.... I did some
basic testing when Paul Stamler's article first came out. A quick
qualitative test made it clear to me that something was going on which
was consistent with Paul's article and that's all I really cared about at
the time. If that's not enough for you, I urge you to make your own
measurements.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Ian Bell[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> Agreed, but no one has made any measurements at all. All we have to go
>> on so far are some subjective listening tests which show that it sound
>> 'different'. They tell you nothing about why.
>
> Perhaps this is worth a more scientific study. Or perhaps not. There are
> many
> things in audio that have been accepted without knowing the reason why they
> work. Sometimes the scientific explanation is discovered, sometimes not.
>
> > However, I do know the
>> inductance of tape replay heads is much higher than that of dynamic
>> mics and tape heads resonate in the over 20KHz region so it is
>> reasonable to suppose dynamic mics will have a resonance much higher
>> than this.
>
> Somewhere on the shelf I have an issue of R-E-P magazine with an article by
> Peter Butt in which he described a very similar experiment in which he put
> shunt resistors across the playback head of a 3M M-79 recorder. He was
> looking at frequency response using a flux loop and found a resistor value
> that flattened out the top end of the frequency response (as he measured
> it)
> and he concluded by listening that his recorder sounded better with the
> resistor
> in place. He described it (perhaps incorrectly) as damping.

I have a very similar article in a 1940s edition of Wireless World which
goes into a lot more technical (and mathematical) detail but the bottom
line is that there is an optimum load resistance for best frequency and
phase response and this is related to the head resonance.

>
> Sometimes we use familiar terms that aren't technically precise, but it
> does help
> to explain things to the layman. And most people in this field today are
> laymen.
>
> Shall we discuss "phase" now? Or "latency?" ;)
>

NO, not again!!


Cheers

Ian

[Don Pearce[_3_]]

On 11 Nov 2009 09:05:59 -0500, (Scott Dorsey) wrote:

>Ian Bell > wrote:
>>Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Scott Dorsey wrote:
>>>>> Ian Bell > wrote:
>>>>>> Yes but we are not talking about the difference between unloaded and
>>>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>>>>> is below 1.
>>>>> Didn't measure it directly, but I sure saw a difference in ringing on
>>>>> a scope. If you want to measure it, I'd be curious what you come up with.
>>>> So when you say 'saw a difference in ringing on the scope' what exactly
>>>> were the test conditions?
>>>
>>> Little baby IEC chamber, tone burst source, 600 and 10K loads into
>>> a Neff differential amp, old Tek 565 scope. Don't recall the burst
>>> frequency but it was probably 5KC or so.
>>
>>So this was a burst of how many cycles of 5KHz and precisely what did
>>you see on the scope?
>
>Probably around a .1 second burst. What I saw on the scope was a nice
>ringing on the trailing edge of the waveform, and that ringing was not at
>the excitation frequency.
>
>Again, it's been quite a few years since I did any of this.... I did some
>basic testing when Paul Stamler's article first came out. A quick
>qualitative test made it clear to me that something was going on which
>was consistent with Paul's article and that's all I really cared about at
>the time. If that's not enough for you, I urge you to make your own
>measurements.
>--scott

If I can lay my hands on a 57 or 58 in the next few days, I will use
my spark impulse generator on it and take a response, with and without
a heavy resistive load. I'll have to hope that the main coupling mode
is acoustic and not electrical.

d

[Arkansan Raider]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> I think the term 'magic load' you used sums it up. I really am not
>> enamoured of these simple changes that 'work magic' in a purely
>> subjective way. I much prefer to understand why and how the effect is
>> produced but that unfortunately demotes from magic to mere science.
>
> Then make the measurement.
> --scott
>

Sounds like work to me. And that's an ugly four-letter word.

/popcorn, sodypop, theater seat, watching the fireworks.

---Jeff

[Mark]

>
> Our two test instruments were a stripped-down drumkit (snare, cymbal
> and kick) and an acoustic guitar, played with fingerpicks in a
> percussive blues style (gentle bare-finger picking didn't tell us
> squat). The difference was most audible on cymbal and guitar.
>
> Peace,
> Paul

Yes you can HEAR a difference, that is not in question.

What is in question is the cause of those differences.

Changing the loading can make changes to the frequency response that
you can hear due to electrical effects that can also be accomplished
by EQ. That was the key question.

There is no evidence that the audible change has anything to do with
mechanical resonances.

Mark

[David Aguilera[_2_]]

Mike Rivers wrote:

> There's always some wise guy in the audience. You're correct of course,
> but I
> didn't mention that in my reply for two reasons:
>
> 1 - the guy probably isn't going to make the measurement as I described
> anyway
> 2 - He's going to ask "what's a good generator that I can buy from eBay?
>
> I'd probably suggest that he use a DAW program to generate a sine wave
> and use his sound card as a generator. If it's something fancier than the
> sound card built into his computer, it will probably have a source
> impedance
> of around 20 ohms.
>
> Alternately, he can build an attenuator which he may need anyway to get the
> generator output low enough not to clip the preamp, and make the shunt
> resistor
> low enough so the generator source impedance is insignificant.
>

Mike,

I was thinking of something along the lines of this:
http://www.zen22142.zen.co.uk/Theory/inzoz.htm.

I have a MOTU 896HD and would use Logic 9's utilities for a generator.

Would that be adequate?

David

[David Aguilera[_2_]]

David Gravereaux wrote:
> This is just Thévenin's Equivalent. Write it out.
>
> If you want a 600 ohm load, solve for Z as the shunt knowing Zpre:
>
> 600 = 1/((1/Zpre)+(1/Z))
> or
> Z = 1/(0.001667 + 1/Zpre)

Very helpful!

Thank you!

[David Aguilera[_2_]]

Mike Rivers wrote:
> geoff wrote:
>
>> Thought you were advocating testing in input impedence of a preamp by
>> hooking a multimeter to it and simply reading the R of the scale..
>
> I think that's what the original poster was dreaming about, but he's
> been told
> that he can't. But he can still make use of his multimeter to make the
> measurement.
> It just takes some extra stuff.

I understood that I could not beforehand, which was why I mentioned AC
electronics.

[David Aguilera[_2_]]

PStamler wrote:
> On Nov 9, 6:15 pm, Mike Rivers > wrote:
>> geoff wrote:
>>> An XLR-M to XLR-F 'barrel' adaptor is tidier.
>> But you'd have to buy it. You can make a short cable out of
>> a long cable, even one that you've junked because it's faulty,
>> as long as you don't use the faulty part.
>
> As the guy who started some of this discussion with an article called
> "The Taming of the Shure" in Recording Magazine, let me weigh in with
> a couple of suggestions.
>
> 1. I don't recommend using barrel connectors; if you put them on the
> preamp/mixer end of the cable, one yank of the cable can badly torque
> the XLR on the mixer/preamp, possibly causing expensive damage. A
> short cable is safer.
>
> 2. Solder the resistor between pins 2 and 3 of the male connector on
> the cable. I recommend the male connector because there's a bit more
> room inside the shell. Even so, you'll need to snip the leads off real
> short. Make sure that, when you solder in the resistor, the cable
> doesn't come unsoldered. This is a lot easier to do properly with a
> Neutrik connector rather than Switchcraft.
>
> 3. If you look at your mixer/preamp's manual, you should find the
> input impedance listed and can compute the proper parallel resistor.
> In the absence of more data, though, for an SM57 a 681 ohm (NOT 681k!)
> resistor will usually give good results.
>
> 4. The improvement is mostly in the area of cleanness and clarity, and
> lack of high-frequency "hashiness". In the comparison I originally
> did, we listened to the SM57 on a drumkit; with a standard load (2k)
> the cymbals sounded more like white noise than the metallic ring a
> cymbal should have. With the parallel resistor, it sounded much more
> like a real cymbal. On acoustic guitar switching to the parallel
> resistor channel took away a lot of the "ringy" quality at high
> frequencies.
>
> 5. I've only found a few microphones that are helped by this
> technique; the most important was the SM57 family (SM56 and SM58
> included). The AKG D112 got a lot less "pillowy" and a lot tighter on
> the bottom, but the jury's out whether that was an improvement. Among
> the mics for which this makes little or no difference are Electro-
> Voice RE15 and RE20 and Shure Beta57 It's not recommended for
> condenser mics.
>
> Peace,
> Paul

Thanks!

[zero[_4_]]

"Ian Bell" > wrote in message
...
> geoff wrote:
>> Ian Bell wrote:

> No, all you said was changing the loading makes a difference. I am not
> disputing that.

Ian,

What you appear to be saying, is applying EQ can produce
the same results.

Ok then. Loading a 1/4 ton in the back of your
pick-up truck will change the behavior of the suspension
in a way that air shocks and an air-ride chair will clearly
NOT make you feel the truck is now without weight.

The 1/4 ton is the parallel resistor, the air-ride &
air-seat are your EQ. You can't simulate a 1/4 ton
of load, without a 1/4 ton of real load. Nor can you
eliminate it.

Say you have the perfect photo of person/object, and the
deal breaker is the background or foreground lighting,
do you fix the lighting,,, or fix the picture in Photoshop?
(btw, I know of no EQ/plug-in that can function as remotely close
in audio, as a photo-editing software does with regards
to pictures.)

So. As to what says you.

Now, I can take the stock crossover in
my one 15" Tannoy, add or remove components, and
then simply patch an EQ into it, to match the
other 15" Tannoy? ...Really? :-P

--
-zero

[zero[_4_]]

"Ian Bell" > wrote in message
...

> I think the term 'magic load' you used sums it up. I really am not
> enamoured of these simple changes that 'work magic' in a purely subjective
> way. I much prefer to understand why and how the effect is produced but
> that unfortunately demotes from magic to mere science.

Please read my response to your post earlier in this thread.

--
-zero

[David Aguilera[_2_]]

David Aguilera wrote:
> Scott,
>
> You mentioned this the other day:
>
> > [snip]
> >
> >Buy some of the old classics. Everyone should have an SM-57, an EV
> >635A, and maybe an RE-20. The first two are very cheap, and all three
> >can be found used. The first two are very touchy about loading and
> >will benefit from a shunt resistor in a barrel connector if you are
> >using a modern transformerless preamp.
> >
> > [snip]
>
> I'm just getting into the electrical side of this field and am really
> curious as to how to go about building the shunt resistor. If you have
> the time to enlighten me I would greatly appreciate it.
>
> The preamp I am using is not giving me what I want out of my 57's and
> EV635A. I've always thought it was an impedance problem, but If I could
> build a box with switchable resistance...well--wow! That's
> straightforward and downright useful!
>
> I don't have a anything that will measure impedance, so I am unsure of
> the impedance of my preamps. Is there a way to measure it with a my
> multimeter sans one?
>
> After that it's like connecting resistance in serial right (I'm really
> weak in AC electronics)?
>
> Thanks,
>
> David

I didn't think this would open the can of worms it seems to have. :)

[zero[_4_]]

"Ian Bell" > wrote in message
...
> hank alrich wrote:
>> Ian Bell > wrote:

>> Suspect in one hand and **** in the other. Which one fills up first?
>>
>
>
> Indeed, but until someone makes an actual measurement my **** is a good as
> yours.

Remember...
Speakers>crossover>swap-o-rama>fix with EQ>not so much.

--
-zero

[zero[_4_]]

"Mark" > wrote in message
...
>
> Yes you can HEAR a difference, that is not in question.
>
> What is in question is the cause of those differences.
>
> Changing the loading can make changes to the frequency response that
> you can hear due to electrical effects that can also be accomplished
> by EQ. That was the key question.
>
> There is no evidence that the audible change has anything to do with
> mechanical resonances.

And if the SM-57 was a loudspeaker for toy solders,
How would you properly correct the crossover network
solely using EQ?

--
-zero

[drichard]

Hi Don,

I look forward to seeing your results. I did the load change mod on a
mic cord a couple of years ago, and have used it with my SM58. To my
"layman" ears it sounds like more than an EQ change to me, but I've
been fooled before. To me it sounds like the mic is "tighter" which is
consistent with what Scott saw.

Question for all: Doesn't the level change as well, when using the
shunt resistor?

Thanks,

Dean

On Nov 11, 8:11*am, (Don Pearce) wrote:
> On 11 Nov 2009 09:05:59 -0500, (Scott Dorsey) wrote:
>
>
>
>
>
> >Ian Bell > wrote:
> >>Scott Dorsey wrote:
> >>> Ian Bell > wrote:
> >>>> Scott Dorsey wrote:
> >>>>> Ian Bell > wrote:
> >>>>>> Yes but we are not talking about the difference between unloaded and
> >>>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
> >>>>>> is below 1.
> >>>>> Didn't measure it directly, but I sure saw a difference in ringing on
> >>>>> a scope. *If you want to measure it, I'd be curious what you come up with.
> >>>> So when you say 'saw a difference in ringing on the scope' what exactly
> >>>> were the test conditions?
>
> >>> Little baby IEC chamber, tone burst source, 600 and 10K loads into
> >>> a Neff differential amp, old Tek 565 scope. *Don't recall the burst
> >>> frequency but it was probably 5KC or so.
>
> >>So this was a burst of how many cycles of 5KHz and precisely what did
> >>you see on the scope?
>
> >Probably around a .1 second burst. *What I saw on the scope was a nice
> >ringing on the trailing edge of the waveform, and that ringing was not at
> >the excitation frequency.
>
> >Again, it's been quite a few years since I did any of this.... I did some
> >basic testing when Paul Stamler's article first came out. *A quick
> >qualitative test made it clear to me that something was going on which
> >was consistent with Paul's article and that's all I really cared about at
> >the time. *If that's not enough for you, I urge you to make your own
> >measurements.
> >--scott
>
> If I can lay my hands on a 57 or 58 in the next few days, I will use
> my spark impulse generator on it and take a response, with and without
> a heavy resistive load. I'll have to hope that the main coupling mode
> is acoustic and not electrical.
>
> d- Hide quoted text -
>
> - Show quoted text -

[Scott Dorsey]

Don Pearce > wrote:
>
>If I can lay my hands on a 57 or 58 in the next few days, I will use
>my spark impulse generator on it and take a response, with and without
>a heavy resistive load. I'll have to hope that the main coupling mode
>is acoustic and not electrical.

If you do it with a 58, take the ball off. The on-axis response is
changed dramatically by the ball and not in a good way.

If possible, I'd be curious if you could do it with the internal
transformer removed as well. That would tell for sure if the ringing
issue was due to the poor quality transformer or the mechanical issues.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[drichard]

I don't consider it a bad thing. The discussion seems mostly civil,
and to me it seems enlightening. The difference between an EQ change
and a change in the damping is worth discussing.


On Nov 11, 10:49*am, David Aguilera
> wrote:
> David Aguilera wrote:
> > Scott,
>
> > You mentioned this the other day:
>
> > *> [snip]
>
> > *>Buy some of the old classics. *Everyone should have an SM-57, an EV
> > *>635A, and maybe an RE-20. *The first two are very cheap, and all three
> > *>can be found used. *The first two are very touchy about loading and
> > *>will benefit from a shunt resistor in a barrel connector if you are
> > *>using a modern transformerless preamp.
>
> > *> [snip]
>
> > I'm just getting into the electrical side of this field and am really
> > curious as to how to go about building the shunt resistor. *If you have
> > the time to enlighten me I would greatly appreciate it.
>
> > The preamp I am using is not giving me what I want out of my 57's and
> > EV635A. *I've always thought it was an impedance problem, but If I could
> > build a box with switchable resistance...well--wow! *That's
> > straightforward and downright useful!
>
> > I don't have a anything that will measure impedance, so I am unsure of
> > the impedance of my preamps. *Is there a way to measure it with a my
> > multimeter sans one?
>
> > After that it's like connecting resistance in serial right (I'm really
> > weak in AC electronics)?
>
> > Thanks,
>
> > David
>
> I didn't think this would open the can of worms it seems to have. *:)- Hide quoted text -
>
> - Show quoted text -

[Don Pearce[_3_]]

On Wed, 11 Nov 2009 09:15:59 -0800 (PST), drichard
> wrote:

>Question for all: Doesn't the level change as well, when using the
>shunt resistor?

Yes, but a very minor tweak on the preamp gain fixes that.

d

[Scott Dorsey]

drichard > wrote:
>
>Question for all: Doesn't the level change as well, when using the
>shunt resistor?

Yes, and so the S/N is reduced a little. A better way to do this is
to use a step-up transformer, which gets you proper loading without
losing signal. Problem is, good transformers are expensive, and
resistors are cheap. You pays your money and you takes your chance.

A good transformer input preamp like the John Hardy is going to give
you a lower noise floor than a Mackie with a shunt resistor, and the
tone won't change when you adjust the gains like it does on the Mackie
either. But you can buy a lot of channels of Mackie for the cost of
one channel of the John Hardy. Life's just like that.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Don Pearce[_3_]]

On 11 Nov 2009 12:26:36 -0500, (Scott Dorsey) wrote:

>drichard > wrote:
>>
>>Question for all: Doesn't the level change as well, when using the
>>shunt resistor?
>
>Yes, and so the S/N is reduced a little. A better way to do this is
>to use a step-up transformer, which gets you proper loading without
>losing signal. Problem is, good transformers are expensive, and
>resistors are cheap. You pays your money and you takes your chance.
>
>A good transformer input preamp like the John Hardy is going to give
>you a lower noise floor than a Mackie with a shunt resistor, and the
>tone won't change when you adjust the gains like it does on the Mackie
>either. But you can buy a lot of channels of Mackie for the cost of
>one channel of the John Hardy. Life's just like that.
>--scott

Even a good transformer will lose you about 1dB of signal, which is
probably no more than the increased loading will cause.

d

[David Aguilera[_2_]]

drichard wrote:
> I don't consider it a bad thing. The discussion seems mostly civil,
> and to me it seems enlightening. The difference between an EQ change
> and a change in the damping is worth discussing.
>

I'm just happy to get all of this information from what I previously
thought was a much simpler question.

[hank alrich]

Scott Dorsey > wrote:

> drichard > wrote:
> >
> >Question for all: Doesn't the level change as well, when using the
> >shunt resistor?
>
> Yes, and so the S/N is reduced a little. A better way to do this is
> to use a step-up transformer, which gets you proper loading without
> losing signal. Problem is, good transformers are expensive, and
> resistors are cheap. You pays your money and you takes your chance.
>
> A good transformer input preamp like the John Hardy is going to give
> you a lower noise floor than a Mackie with a shunt resistor, and the
> tone won't change when you adjust the gains like it does on the Mackie
> either. But you can buy a lot of channels of Mackie for the cost of
> one channel of the John Hardy. Life's just like that.
> --scott

No matter how many Mackie preamp channels one buys for their money, they
will not get even in the same ballpark as a Hardy preamp if intended use
includes plenty of dynamic mics.

--
ha
shut up and play your guitar

[hank alrich]

Ian Bell > wrote:

> Mike Rivers wrote:
> > Ian Bell wrote:
> >
> >> Yes but we are not talking about the difference between unloaded and
> >> loaded but between a 2K load and a 680R load. In both case I bet the Q
> >> is below 1.
> >
> > Borrow an SM57 and try it. Tell me the input impedance of the preamp you'll
> > be using and I'll send you a resistor. Then perhaps you can better
> > analyze what
> > you hear. Or better yet, measure it.
>
>
> I agree, it needs to be measured. Until then no one is 'right'.
>
> Cheers
>
> Ian

At some point, just to get audio work of the recording kind accomplished
some of us have to make decisions based on what we hear, on the spot. It
is a simple thing to hear the difference loading makes on those old
Shures. Move one from a 1202 to a Great River and one could think one
switched mics instead of preamps.

--
ha
shut up and play your guitar

[hank alrich]

Ian Bell > wrote:

> hank alrich wrote:
> > Ian Bell > wrote:
> >
> >> geoff wrote:
> >>> Ian Bell wrote:
> >>>
> >>>> Personally I doubt that is a factor. The Q of the average dynamic mic
> >>>> is so low that changing the load this way will make little difference.
> >>>>
> >>> Given the easily-heard results with a humble SM57, a simple change in
> >>> loading clearly does make a difference.
> >>>
> >>> If you are skeptical, try it !
> >>>
> >>> geoff
> >>>
> >>>
> >> You miss the point. I am suggesting that loading does nothing that EQ
> >> will not achieve and with greater flexibility.
> >>
> >> Cheers
> >>
> >> Ian
> >
> > But it does, and that is the point of suggesting you TRY it.
>
>
> There is no evidence it does. All we have so far is subjective
> statements. No one has made any measurements.
>
> Cheers
>
> Ian
> >
> > You assume this and that - so much for empirical empirical.
> >

Deaf mo'fo's don't work long in the studio. Blind? Yes. Deaf? No.

****, if I had to stop and measure for evey decision I made last week,
let alone for each collective sonic choice made by all involved, we'd
still be trying to get around to tracking the second song. As it is
we'll do three tiny tweaks of 1 dB or less this afternoon and we're
wrapped in production but for mastering, tomorrow.

I don't dismiss science or the value of testing, ABX or otherwise. But
when work needs to get done few of us can stop the show to drag out the
test gear unless we aspire to be labelled an "Unproducer".

--
ha
shut up and play your guitar

[hank alrich]

Ian Bell > wrote:

> Mike Rivers wrote:
> > Ian Bell wrote:
> >
> >> All we have so far is subjective statements. No one has made any
> >> measurements.
> >
> > Including you. Unless you've tried "the magic load" you can't
> > even subjectively say that you can duplicate the results with
> > equalization.
> >
> > I understand, though, that you like to argue and debate. We all
> > do, around here. We have no lives. It's what we do.
>
>
> I think the term 'magic load' you used sums it up. I really am not
> enamoured of these simple changes that 'work magic' in a purely
> subjective way. I much prefer to understand why and how the effect is
> produced but that unfortunately demotes from magic to mere science.
>
> Cheers
>
> Ian

Figuring out why the effect results from a change in load in no way
negates the outright sonic MAGIC of the change.

--
ha
shut up and play your guitar

[hank alrich]

PStamler > wrote:

> And, just to be clear, the two channels had input impedances of 2k and
> 500 ohms, respectively. The 681 ohm resistor in parallel with a
> typical tranformerless-preamp impedance of 1800-2200 gives about 500
> ohms, which is why I suggested it as a first try.
>
> As Scott says, we're dealing here with a mechanical resonance, NOT an
> electrical resonance.
>
> Mr. Bell should try the experiment before belittling it further. It
> won't cost much; heck, he could add the resistor to a mic cable he
> isn't using, and snip it out afterwards.
>
> One thing that's important, though, is to match levels very carefully.
> After setting the level on channel 1, we put the mic in front of a
> guitar amplifier that had a 700Hz tone running through it. We used
> that to match the levels of the two preamp channels (with their
> different input Zs) to within a pointer-width on a standard VU meter,
> or about 0.1dB. If you don't do the match that closely, the test is
> meaningless.
>
> Our two test instruments were a stripped-down drumkit (snare, cymbal
> and kick) and an acoustic guitar, played with fingerpicks in a
> percussive blues style (gentle bare-finger picking didn't tell us
> squat). The difference was most audible on cymbal and guitar.
>
> Peace,
> Paul

Transients seem to bring out the differences IME, based on 57's and 58's
through Mackies and A&H's, versus Great River MP2-MH and MP4, Neve
modules, the Phoenix/Aurora GTQ2, etc.

--
ha
shut up and play your guitar

[hank alrich]

Ian Bell > wrote:

> hank alrich wrote:
> > Ian Bell > wrote:
> >
> >> Mike Rivers wrote:
> >>> Ian Bell wrote:
> >>>
> >>>> Since when has a 'standard' load been 2K??
> >>> It's sort of a roughly weighted average of the input impedance of
> >>> a good many modern transformerless preamps and mixing consoles.
> >>> This is typical of the gear to which an SM57 is likely to be connected,
> >>> at least among the Recording Magazine readership, where Paul's
> >>> article was published.
> >>>
> >>> Perhaps "typical" would have been a better term, unless (and I don't
> >>> recall the details of the study) a specific load resistor for each preamp
> >>> was chosen so that the mic would be loaded by 2K for any preamp
> >>> in the study. This would allow the preamp to be the major source of
> >>> differences in sound when used with an SM57.
> >>>
> >>> Further listening experiments indicated that the mic sounded better
> >>> when loaded with 600 ohms (adjusted for the preamp used for testing).
> >>>
> >>>> Dynamic mics are basically inductive which means their impedance rises
> >>>> with frequency. By loading it with 680R instead of 2K you effectively
> >>>> hit the high frequency response - something you can do with infinitely
> >>>> more precision using EQ.
> >>> More important, you change the damping of the diaphragm assembly,
> >>> which broadens resonant peaks and may even change the frequency
> >>> of some resonances. That's not easily done with EQ.
> >>>
> >>
> >> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
> >> mic is so low that this is not a factor.
> >>
> >>
> >> Cheers
> >>
> >> ian
> >
> > Suspect in one hand and **** in the other. Which one fills up first?
> >
>
>
> Indeed, but until someone makes an actual measurement my **** is a good
> as yours.
>
> Cheers
>
> Ian

I got one hand full of experience and the other full of music.

--
ha
shut up and play your guitar

[Arkansan Raider]

David Aguilera wrote:
> drichard wrote:
>> I don't consider it a bad thing. The discussion seems mostly civil,
>> and to me it seems enlightening. The difference between an EQ change
>> and a change in the damping is worth discussing.
>>
>
> I'm just happy to get all of this information from what I previously
> thought was a much simpler question.

Preach it.

---Jeff

[Arkansan Raider]

Scott Dorsey wrote:
> drichard > wrote:
>> Question for all: Doesn't the level change as well, when using the
>> shunt resistor?
>
> Yes, and so the S/N is reduced a little. A better way to do this is
> to use a step-up transformer, which gets you proper loading without
> losing signal. Problem is, good transformers are expensive, and
> resistors are cheap. You pays your money and you takes your chance.
>
> A good transformer input preamp like the John Hardy is going to give
> you a lower noise floor than a Mackie with a shunt resistor, and the
> tone won't change when you adjust the gains like it does on the Mackie
> either. But you can buy a lot of channels of Mackie for the cost of
> one channel of the John Hardy. Life's just like that.
> --scott
>

Okay, I feel like this might be a dumb question based on the price
level, but I've been looking at the ART MPA and I'm wondering where its
quality falls on the Mackie/John Hardy continuum.

The thing that got my attention was the variable input impedance, and it
seems to have gotten some good reviews.

Any takers?

---Jeff

[Mike Rivers]

Ian Bell wrote:

> I much prefer to understand why and how the effect is
> produced but that unfortunately demotes from magic to mere science.

Really, I do too. But I don't let the lack of pure scientific understanding
get in the way of using sometking that works for me.

I'm glad hummingbirds can fly, too.

[Mike Rivers]

Ian Bell wrote:

> I have a very similar article in a 1940s edition of Wireless World which
> goes into a lot more technical (and mathematical) detail but the bottom
> line is that there is an optimum load resistance for best frequency and
> phase response and this is related to the head resonance.

It's easier to understand and explain when dealing with tape heads, because
there's no (at least there should be no) mechanical part to the frequency
and phase response anomalies. But this is a different kind of source than a
microphone.

[Don Pearce[_3_]]

On Wed, 11 Nov 2009 13:50:33 +0000, Ian Bell >
wrote:

>Mike Rivers wrote:
>> Ian Bell wrote:
>>
>>> All we have so far is subjective statements. No one has made any
>>> measurements.
>>
>> Including you. Unless you've tried "the magic load" you can't
>> even subjectively say that you can duplicate the results with
>> equalization.
>>
>> I understand, though, that you like to argue and debate. We all
>> do, around here. We have no lives. It's what we do.
>
>
>I think the term 'magic load' you used sums it up. I really am not
>enamoured of these simple changes that 'work magic' in a purely
>subjective way. I much prefer to understand why and how the effect is
>produced but that unfortunately demotes from magic to mere science.
>

You mean promotes mere magic to real science, surely?

d

[Mike Rivers]

Ian Bell wrote:

> Looking at Shure's own data sheet all it says is:
>
> "Rated impedance is 150Ω (310Ω actual) for connection to
> microphone inputs rated low impedance"

Now what in the world does THAT mean? Sounds like it came from
a spec sheet. Oh . . . never mind.


>> [Scott] I have, as I said, made some basic qualitative measurements showing
>> ringing. If you want to do a full impulse response, I'd love to see it.

> And I have asked you to specify exactly how those measurements were made.

I suppose you could connect the outputs of the mic to an oscilloscope
(or a DAW,
for an easier look-later picture), fire a pistol in front of it, and
look at the decay part
of the waveform with various loads.

[Don Pearce[_3_]]

On Wed, 11 Nov 2009 13:51:31 -0500, Mike Rivers >
wrote:

>Ian Bell wrote:
>
>> Looking at Shure's own data sheet all it says is:
>>
>> "Rated impedance is 150Ω (310Ω actual) for connection to
>> microphone inputs rated low impedance"
>
>Now what in the world does THAT mean? Sounds like it came from
>a spec sheet. Oh . . . never mind.
>
>
>>> [Scott] I have, as I said, made some basic qualitative measurements showing
>>> ringing. If you want to do a full impulse response, I'd love to see it.
>
>> And I have asked you to specify exactly how those measurements were made.
>
>I suppose you could connect the outputs of the mic to an oscilloscope
>(or a DAW,
>for an easier look-later picture), fire a pistol in front of it, and
>look at the decay part
>of the waveform with various loads.

A 58? No, fire the pistol "at" it.

d

[Mike Rivers]

drichard wrote:

> Question for all: Doesn't the level change as well, when using the
> shunt resistor?

Yes, it'll be lower, just like Mr. Ohm predicts. This is why Paul emphasized
the need to accurately match levels using an acoustic source. You can't just
set both preamp channel knobs to 40 dB or whatever you need. Otherwise
the difference between levels can through off your subjective evaluation.

"Louder sounds better" you know.

[Scott Dorsey]

Arkansan Raider > wrote:
>Okay, I feel like this might be a dumb question based on the price
>level, but I've been looking at the ART MPA and I'm wondering where its
>quality falls on the Mackie/John Hardy continuum.

It's substantially lower than the Mackie. It's a Mackie-style input stage,
but then it goes into this cheesy tube distortion stage that doesn't act
like a conventional tube stage at all.

>The thing that got my attention was the variable input impedance, and it
>seems to have gotten some good reviews.

The variable input Z is accomplished with shunt resistors, just like the
cable gadget being discussed here.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers]

Arkansan Raider wrote:

> Okay, I feel like this might be a dumb question based on the price
> level, but I've been looking at the ART MPA and I'm wondering where its
> quality falls on the Mackie/John Hardy continuum.

Probably closer to the Mackie than the Hardy, only with more distortion and
cooler meters. Note what ART says about the variable impedance:

"The ability to vary the input impedance of a microphone preamplifier
changes the load the microphone ‘sees’ in the system, dramatically
altering its performance and sonic character. This creates a wide range
of new sonic possibilities with any modern or vintage condenser, ribbon
or dynamic microphone."

The operative phrase here is "creates a wide range of new sonic
possibilities" - in
other words, it makes the microphone sound different as you twiddle the
knob.
This can be a good thing or a bad thing. Good because you might be able
to find
a setting that makes it sound better to your ear, for that mic, and that
application.
Bad because you feel obligated to fool around with the control because
it's there,
delaying the recording and perhaps getting a less inspired performance.

[Mike Rivers]

David Aguilera wrote:

> I was thinking of something along the lines of this:
> http://www.zen22142.zen.co.uk/Theory/inzoz.htm.

Sure, that'll work. You're measuring the voltage drop across
the series resistor by measuring the voltage going in and coming
out, and using that to calculate the current since you know the
value of the resistor. By knowing the current and the voltage
drop across the preamp input, you can calculate the preamp's
impedance. The half-voltage-measure-the-pot method is quicker
as long as you have a source that's of sufficiently low impedance
to be ignored.

> I have a MOTU 896HD and would use Logic 9's utilities for a generator.

I suppose that would work. You can measure the impedance of the
generator too, and throw that into your calculation if you want a better
answer.

[Mike Rivers]

David Aguilera wrote:

> I'm just happy to get all of this information from what I previously
> thought was a much simpler question.

If you have to ask, it's not a simple question. <g>

[Arkansan Raider]

Okay, cool. Thanks for the info, both of you!

---Jeff


Mike Rivers wrote:
> Arkansan Raider wrote:
>
>> Okay, I feel like this might be a dumb question based on the price
>> level, but I've been looking at the ART MPA and I'm wondering
>> where its quality falls on the Mackie/John Hardy continuum.
>
> Probably closer to the Mackie than the Hardy, only with more
> distortion and cooler meters. Note what ART says about the variable
> impedance:
>
> "The ability to vary the input impedance of a microphone preamplifier
> changes the load the microphone ‘sees’ in the system, dramatically
> altering its performance and sonic character. This creates a wide
> range of new sonic possibilities with any modern or vintage
> condenser, ribbon or dynamic microphone."
>
> The operative phrase here is "creates a wide range of new sonic
> possibilities" - in other words, it makes the microphone sound
> different as you twiddle the knob. This can be a good thing or a bad
> thing. Good because you might be able to find a setting that makes it
> sound better to your ear, for that mic, and that application. Bad
> because you feel obligated to fool around with the control because
> it's there, delaying the recording and perhaps getting a less
> inspired performance.
>



Scott Dorsey wrote:
> Arkansan Raider > wrote:
>> Okay, I feel like this might be a dumb question based on the price
>> level, but I've been looking at the ART MPA and I'm wondering where
>> its quality falls on the Mackie/John Hardy continuum.
>
> It's substantially lower than the Mackie. It's a Mackie-style input
> stage, but then it goes into this cheesy tube distortion stage that
> doesn't act like a conventional tube stage at all.
>
>> The thing that got my attention was the variable input impedance,
>> and it seems to have gotten some good reviews.
>
> The variable input Z is accomplished with shunt resistors, just like
> the cable gadget being discussed here. --scott

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Well, if you want to throw mechanical resonances into the pot as well
>>>> that's fine by me. However, dynamic mic manufacturers aim to get the
>>>> main resonance as low as possible because the response drops like a
>>>> stone below it - they aim for as much of the response as possible to be
>>>> above resonance. Looking at the SM57 frequency response it clearly
>>>> drops off steeply below 200Hz so my guess it that is where the main
>>>> resonance is.
>>> If the mike is loaded properly, yes. The response plots that you see
>>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
>>> the like).
>> Are you certain. Looking at Shure's own data sheet all it says is:
>>
>> "Rated impedance is 150Ω (310Ω actual) for connection to
>> microphone inputs rated low impedance"
>>
>> There is no mention at all of the test cinditions under which frequency
>> response is measured.
>
> That's true, and that's why all the confusion has occurred over the years.
> But you'd expect that the companion mike mixer that Shure sold at the
> time, for instance, would be a good match for it.
>
> "Low impedance" would be something in the 500-600 ohm region. Olsen's
> book has a good description of how bridging loads on microphones work.
> --scott
>

The strange thing is, the Shure spec says 'rated impedance' 150R (actual
310R) which would result in a 3.6dB loss into a 600R load - then again
they were never intended for very quiet sounds ;-)

Cheers

Ian

[Ian Bell[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> Looking at Shure's own data sheet all it says is:
>>
>> "Rated impedance is 150Ω (310Ω actual) for connection to
>> microphone inputs rated low impedance"
>
> Now what in the world does THAT mean? Sounds like it came from
> a spec sheet. Oh . . . never mind.
>


Someone has been spoofing my address - I never wrote that.

Cheers

Ian
>
>>> [Scott] I have, as I said, made some basic qualitative measurements
>>> showing
>>> ringing. If you want to do a full impulse response, I'd love to see it.
>
>> And I have asked you to specify exactly how those measurements were made.
>
> I suppose you could connect the outputs of the mic to an oscilloscope
> (or a DAW,
> for an easier look-later picture), fire a pistol in front of it, and
> look at the decay part
> of the waveform with various loads.

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Scott Dorsey wrote:
>>>>> Ian Bell > wrote:
>>>>>> Yes but we are not talking about the difference between unloaded and
>>>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>>>>> is below 1.
>>>>> Didn't measure it directly, but I sure saw a difference in ringing on
>>>>> a scope. If you want to measure it, I'd be curious what you come up with.
>>>> So when you say 'saw a difference in ringing on the scope' what exactly
>>>> were the test conditions?
>>> Little baby IEC chamber, tone burst source, 600 and 10K loads into
>>> a Neff differential amp, old Tek 565 scope. Don't recall the burst
>>> frequency but it was probably 5KC or so.
>> So this was a burst of how many cycles of 5KHz and precisely what did
>> you see on the scope?
>
> Probably around a .1 second burst. What I saw on the scope was a nice
> ringing on the trailing edge of the waveform, and that ringing was not at
> the excitation frequency.
>
> Again, it's been quite a few years since I did any of this.... I did some
> basic testing when Paul Stamler's article first came out. A quick
> qualitative test made it clear to me that something was going on which
> was consistent with Paul's article and that's all I really cared about at
> the time. If that's not enough for you, I urge you to make your own
> measurements.
> --scott
>
>


No, that's quite enough for me. I am just glad someone actually made
some real measurements.

Cheers

Ian

[Ian Bell[_2_]]

Don Pearce wrote:
> On 11 Nov 2009 09:05:59 -0500, (Scott Dorsey) wrote:
>
>> Ian Bell > wrote:
>>> Scott Dorsey wrote:
>>>> Ian Bell > wrote:
>>>>> Scott Dorsey wrote:
>>>>>> Ian Bell > wrote:
>>>>>>> Yes but we are not talking about the difference between unloaded and
>>>>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>>>>>> is below 1.
>>>>>> Didn't measure it directly, but I sure saw a difference in ringing on
>>>>>> a scope. If you want to measure it, I'd be curious what you come up with.
>>>>> So when you say 'saw a difference in ringing on the scope' what exactly
>>>>> were the test conditions?
>>>> Little baby IEC chamber, tone burst source, 600 and 10K loads into
>>>> a Neff differential amp, old Tek 565 scope. Don't recall the burst
>>>> frequency but it was probably 5KC or so.
>>> So this was a burst of how many cycles of 5KHz and precisely what did
>>> you see on the scope?
>> Probably around a .1 second burst. What I saw on the scope was a nice
>> ringing on the trailing edge of the waveform, and that ringing was not at
>> the excitation frequency.
>>
>> Again, it's been quite a few years since I did any of this.... I did some
>> basic testing when Paul Stamler's article first came out. A quick
>> qualitative test made it clear to me that something was going on which
>> was consistent with Paul's article and that's all I really cared about at
>> the time. If that's not enough for you, I urge you to make your own
>> measurements.
>> --scott
>
> If I can lay my hands on a 57 or 58 in the next few days, I will use
> my spark impulse generator on it and take a response, with and without
> a heavy resistive load. I'll have to hope that the main coupling mode
> is acoustic and not electrical.
>
> d


Excellent.Looking forward to the results.

Cheers

Ian

[Ian Bell[_2_]]

drichard wrote:
> Hi Don,
>
> I look forward to seeing your results. I did the load change mod on a
> mic cord a couple of years ago, and have used it with my SM58. To my
> "layman" ears it sounds like more than an EQ change to me, but I've
> been fooled before. To me it sounds like the mic is "tighter" which is
> consistent with what Scott saw.
>
> Question for all: Doesn't the level change as well, when using the
> shunt resistor?
>

Yup.

Ian


> Thanks,
>
> Dean
>

[Ian Bell[_2_]]

Scott Dorsey wrote:
> drichard > wrote:
>> Question for all: Doesn't the level change as well, when using the
>> shunt resistor?
>
> Yes, and so the S/N is reduced a little. A better way to do this is
> to use a step-up transformer, which gets you proper loading without
> losing signal. Problem is, good transformers are expensive, and
> resistors are cheap. You pays your money and you takes your chance.
>

Er, maybe I am missing something again, but is that not the purpose of
the step up transformer built into the 57??

Cheers

Ian

> A good transformer input preamp like the John Hardy is going to give
> you a lower noise floor than a Mackie with a shunt resistor, and the
> tone won't change when you adjust the gains like it does on the Mackie
> either. But you can buy a lot of channels of Mackie for the cost of
> one channel of the John Hardy. Life's just like that.
> --scott
>

[Ian Bell[_2_]]

hank alrich wrote:
> Ian Bell > wrote:
>
>> Mike Rivers wrote:
>>> Ian Bell wrote:
>>>
>>>> Yes but we are not talking about the difference between unloaded and
>>>> loaded but between a 2K load and a 680R load. In both case I bet the Q
>>>> is below 1.
>>> Borrow an SM57 and try it. Tell me the input impedance of the preamp you'll
>>> be using and I'll send you a resistor. Then perhaps you can better
>>> analyze what
>>> you hear. Or better yet, measure it.
>>
>> I agree, it needs to be measured. Until then no one is 'right'.
>>
>> Cheers
>>
>> Ian
>
> At some point, just to get audio work of the recording kind accomplished
> some of us have to make decisions based on what we hear, on the spot. It
> is a simple thing to hear the difference loading makes on those old
> Shures. Move one from a 1202 to a Great River and one could think one
> switched mics instead of preamps.
>


Quite so, and you will get more change in 'tone' by simply moving the
mic an inch or two.

Cheers

ian

[Ian Bell[_2_]]

zero wrote:
> "Ian Bell" > wrote in message
> ...
>> geoff wrote:
>>> Ian Bell wrote:
>
>> No, all you said was changing the loading makes a difference. I am not
>> disputing that.
>
> Ian,
>
> What you appear to be saying, is applying EQ can produce
> the same results.
>
> Ok then. Loading a 1/4 ton in the back of your
> pick-up truck will change the behavior of the suspension
> in a way that air shocks and an air-ride chair will clearly
> NOT make you feel the truck is now without weight.
>
> The 1/4 ton is the parallel resistor, the air-ride &
> air-seat are your EQ. You can't simulate a 1/4 ton
> of load, without a 1/4 ton of real load. Nor can you
> eliminate it.
>

I am saying the Q is already low so there's already a 1/4 ton weight
bar a few pounds loaded on the truck and when you add the parallel
resistor its like adding just a few more pounds. You will not notice the
difference in ride.



Cheers

ian

> Say you have the perfect photo of person/object, and the
> deal breaker is the background or foreground lighting,
> do you fix the lighting,,, or fix the picture in Photoshop?
> (btw, I know of no EQ/plug-in that can function as remotely close
> in audio, as a photo-editing software does with regards
> to pictures.)
>
> So. As to what says you.
>
> Now, I can take the stock crossover in
> my one 15" Tannoy, add or remove components, and
> then simply patch an EQ into it, to match the
> other 15" Tannoy? ...Really? :-P
>
> --
> -zero
>
>
>

[Ian Bell[_2_]]

zero wrote:
> "Ian Bell" > wrote in message
> ...
>> hank alrich wrote:
>>> Ian Bell > wrote:
>
>>> Suspect in one hand and **** in the other. Which one fills up first?
>>>
>>
>> Indeed, but until someone makes an actual measurement my **** is a good as
>> yours.
>
> Remember...
> Speakers>crossover>swap-o-rama>fix with EQ>not so much.
>
> --
> -zero
>
>


See my reply to your earlier post.

Cheers

Ian

[Ian Bell[_2_]]

hank alrich wrote:
> Ian Bell > wrote:
>
>> Mike Rivers wrote:
>>> Ian Bell wrote:
>>>
>>>> All we have so far is subjective statements. No one has made any
>>>> measurements.
>>> Including you. Unless you've tried "the magic load" you can't
>>> even subjectively say that you can duplicate the results with
>>> equalization.
>>>
>>> I understand, though, that you like to argue and debate. We all
>>> do, around here. We have no lives. It's what we do.
>>
>> I think the term 'magic load' you used sums it up. I really am not
>> enamoured of these simple changes that 'work magic' in a purely
>> subjective way. I much prefer to understand why and how the effect is
>> produced but that unfortunately demotes from magic to mere science.
>>
>> Cheers
>>
>> Ian
>
> Figuring out why the effect results from a change in load in no way
> negates the outright sonic MAGIC of the change.
>


You seriously expect sonic MAGIC from a 57?

Cheers

Ian

[hank alrich]

Ian Bell > wrote:

> hank alrich wrote:
> > Ian Bell > wrote:
> >
> >> Mike Rivers wrote:
> >>> Ian Bell wrote:
> >>>
> >>>> Yes but we are not talking about the difference between unloaded and
> >>>> loaded but between a 2K load and a 680R load. In both case I bet the
> >>>Q > is below 1. Borrow an SM57 and try it. Tell me the input impedance
> >>>of the preamp you'll be using and I'll send you a resistor. Then
> >>>perhaps you can better analyze what you hear. Or better yet, measure
> >>>it.
> >>
> >> I agree, it needs to be measured. Until then no one is 'right'.
> >>
> >> Cheers
> >>
> >> Ian
> >
> > At some point, just to get audio work of the recording kind accomplished
> > some of us have to make decisions based on what we hear, on the spot. It
> > is a simple thing to hear the difference loading makes on those old
> > Shures. Move one from a 1202 to a Great River and one could think one
> > switched mics instead of preamps.
> >
>
>
> Quite so, and you will get more change in 'tone' by simply moving the
> mic an inch or two.
>
> Cheers
>
> ian

Obviously. But if the mic is sucking into what it's feeding, you'll get
a different tone that still sucks, because nothing has changed about the
way the mic responds.

Further, given the head-on live, no isolation, no headphones approach to
what I've just been working on, freedom of mic placement has severe
boundaries. I need the mics to sound as good as possible given where I
have to put them in order to have some control in mixdown.

If this trio had been performing several nights a week for the last
couple of months I could have tracked it all into a good stereo pair. We
don't yet have that luxury, but we're hoping to get there from here.

--
ha
shut up and play your guitar

[Scott Dorsey]

Ian Bell > wrote:
>
>The strange thing is, the Shure spec says 'rated impedance' 150R (actual
>310R) which would result in a 3.6dB loss into a 600R load - then again
>they were never intended for very quiet sounds ;-)

Right. Read Olsen's book on the subject. It's a historical abberation
how we got here.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Ian Bell > wrote:
>
>No, that's quite enough for me. I am just glad someone actually made
>some real measurements.

But I _didn't_ do it with the transformer removed. There's still a chance
that what I was seeing was resulting from the transformer issues. I don't think
it was, but I didn't test for it.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Ian Bell[_2_]]

hank alrich wrote:
> Ian Bell > wrote:
>
>> hank alrich wrote:
>>> Ian Bell > wrote:
>>>
>>>> Mike Rivers wrote:
>>>>> Ian Bell wrote:
>>>>>
>>>>>> Since when has a 'standard' load been 2K??
>>>>> It's sort of a roughly weighted average of the input impedance of
>>>>> a good many modern transformerless preamps and mixing consoles.
>>>>> This is typical of the gear to which an SM57 is likely to be connected,
>>>>> at least among the Recording Magazine readership, where Paul's
>>>>> article was published.
>>>>>
>>>>> Perhaps "typical" would have been a better term, unless (and I don't
>>>>> recall the details of the study) a specific load resistor for each preamp
>>>>> was chosen so that the mic would be loaded by 2K for any preamp
>>>>> in the study. This would allow the preamp to be the major source of
>>>>> differences in sound when used with an SM57.
>>>>>
>>>>> Further listening experiments indicated that the mic sounded better
>>>>> when loaded with 600 ohms (adjusted for the preamp used for testing).
>>>>>
>>>>>> Dynamic mics are basically inductive which means their impedance rises
>>>>>> with frequency. By loading it with 680R instead of 2K you effectively
>>>>>> hit the high frequency response - something you can do with infinitely
>>>>>> more precision using EQ.
>>>>> More important, you change the damping of the diaphragm assembly,
>>>>> which broadens resonant peaks and may even change the frequency
>>>>> of some resonances. That's not easily done with EQ.
>>>>>
>>>> Indeed, but as I said elsewhere, I suspect the Q of the average dynamic
>>>> mic is so low that this is not a factor.
>>>>
>>>>
>>>> Cheers
>>>>
>>>> ian
>>> Suspect in one hand and **** in the other. Which one fills up first?
>>>
>>
>> Indeed, but until someone makes an actual measurement my **** is a good
>> as yours.
>>
>> Cheers
>>
>> Ian
>
> I got one hand full of experience and the other full of music.
>


Hank, I have a lot of respect for you. I know you are busy making and
recoding music and don't have time for the technical nitty gritty.
That's fine.

I am retired. I still record music - just an album a year. I also design
and build tube mic pres. So, I have more time (and inclination) to
investigate these 'techniques' in more detail.

YMMV

Cheers

Ian

[Ian Bell[_2_]]

Don Pearce wrote:
> On Wed, 11 Nov 2009 13:50:33 +0000, Ian Bell >
> wrote:
>
>> Mike Rivers wrote:
>>> Ian Bell wrote:
>>>
>>>> All we have so far is subjective statements. No one has made any
>>>> measurements.
>>> Including you. Unless you've tried "the magic load" you can't
>>> even subjectively say that you can duplicate the results with
>>> equalization.
>>>
>>> I understand, though, that you like to argue and debate. We all
>>> do, around here. We have no lives. It's what we do.
>>
>> I think the term 'magic load' you used sums it up. I really am not
>> enamoured of these simple changes that 'work magic' in a purely
>> subjective way. I much prefer to understand why and how the effect is
>> produced but that unfortunately demotes from magic to mere science.
>>
>
> You mean promotes mere magic to real science, surely?
>
> d


I would like to think that but is seems people prefer magic to science.

Cheers

Ian

[Scott Dorsey]

Ian Bell > wrote:
>Scott Dorsey wrote:
>> drichard > wrote:
>>> Question for all: Doesn't the level change as well, when using the
>>> shunt resistor?
>>
>> Yes, and so the S/N is reduced a little. A better way to do this is
>> to use a step-up transformer, which gets you proper loading without
>> losing signal. Problem is, good transformers are expensive, and
>> resistors are cheap. You pays your money and you takes your chance.
>
>Er, maybe I am missing something again, but is that not the purpose of
>the step up transformer built into the 57??

It is! the thing is, the 57 was designed in an era when typical mike
preamps had much lower input Z than they do today.

If someone were designing the 57 today, they might choose to use a higher
ratio transformer inside. Or they might choose to make the magnetic
coupling of the element more lossy so that loading wasn't as critical.

I do know that in the seventies it was a big deal to remove the
transformer from an SM-57 and plug it straight into the 600 ohm input
of a console. This changed the sound and made it bright and rattly
(which I again attribute to mechanical damping), which a lot of people
found to be a cool effect on snare drum.

People forget today that the SM-57 is really a holdover from a different
era in audio altogether.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[darrelld]

I toally agree with Geoff in the face of the learned opposition (and
thanks for the idea to do this in the first place Paul!)

I made up barrels with the shunt resister for all of my SM57's. I made
some polarity inverters at the same time. I labeled them all
appropriately and always plug them into the mic to avoid possible
"torque" damage to a mixing board.

The expense was modest. The work was super easy and I don't have to
keep track of special use mic cables. If it's an adapter, it looks
like an adapter because it's in a barrel.

This works for me. YMMV.

On Nov 9, 2:57*pm, "geoff" > wrote:
> Mike Rivers wrote:
> > David Aguilera wrote:
>
> >> I'm just getting into the electrical side of this field and am really
> >> curious as to how to go about building the shunt resistor. *If you
> >> have the time to enlighten me I would greatly appreciate it.
>
> > Make up a short (1 foot or so) mic cable with a resistor connected
> > between pins 2 and 3 of the XLR connector on one end.
>
> An XLR-M to XLR-F 'barrel' adaptor is tidier.
>
> geoff

[Geoff]

Ian Bell wrote:
> PStamler wrote:

> I'll say it again, I do not dispute that loading an SM57 alters the
> way it sounds. What we are discussion is the MECHANISM that causes that
> change.

Easy-peasy.

Try a loaded SM57 versus and unloaded and EQ one, and observe the ringing
still on the EQed one.

> I never disagreed that there is an audible difference.

I thought you were inferring that the electrical changes were not sufficient
to have an effect that could be described as significant.

geoff

[Geoff]

Ian Bell wrote:

> I am retired. I still record music - just an album a year. I also
> design and build tube mic pres. So, I have more time (and
> inclination) to investigate these 'techniques' in more detail.

It should take you about 30 minutes - try it.

geoff

[Geoff]

Ian Bell wrote:

>>
>
>
> Well, if you want to throw mechanical resonances into the pot as well
> that's fine by me.

Throw them into the pot ? They were always the 90% of the pot content.

geoff

[Geoff]

Ian Bell wrote:

> And I have asked you to specify exactly how those measurements were
> made.


When I did it I :
1 - Put a loaded '57 into one channel.
2 - Put an unloaded one into the next channel.
3 - Matched the record levels.
4 - Recorded a sharp percussive impulse (clicking a pair of drumsticks) in a
moderately dead acoustic.
5 - Looked at the result in Sound Forge.

I didn't do the EQ thing, because the visual (and audible) difference was so
obvious - the nature of that difference would not have been alterred by a
few dB of treble EQ.

Try it. It should take far less time than you've spent typing here.

geoff

[Geoff]

Ian Bell wrote:
> Mike Rivers wrote:
>> Ian Bell wrote:
>>
>>> Yes but we are not talking about the difference between unloaded and
>>> loaded but between a 2K load and a 680R load. In both case I bet
>>> the Q is below 1.
>>
>> Borrow an SM57 and try it. Tell me the input impedance of the preamp
>> you'll be using and I'll send you a resistor. Then perhaps you can
>> better analyze what
>> you hear. Or better yet, measure it.
>
>
> I agree, it needs to be measured. Until then no one is 'right'.

But those who have actually done some investigation rather that blanket
denial are more right than you !


geoff

[Geoff]

Ian Bell wrote:

> Quite so, and you will get more change in 'tone' by simply moving the
> mic an inch or two.


'Tone' is not the major parameter that is changing here.

geoff

[Ian Bell[_2_]]

Scott Dorsey wrote:
> Ian Bell > wrote:
>> No, that's quite enough for me. I am just glad someone actually made
>> some real measurements.
>
> But I _didn't_ do it with the transformer removed.


But most folk will use it with the transformer installed will they not.

Cheers

Ian
There's still a chance
> that what I was seeing was resulting from the transformer issues. I don't think
> it was, but I didn't test for it.
> --scott

[Ian Bell[_2_]]

geoff wrote:
> Ian Bell wrote:
>> PStamler wrote:
>
>> I'll say it again, I do not dispute that loading an SM57 alters the
>> way it sounds. What we are discussion is the MECHANISM that causes that
>> change.
>
> Easy-peasy.
>
> Try a loaded SM57 versus and unloaded and EQ one, and observe the ringing
> still on the EQed one.
>
>> I never disagreed that there is an audible difference.
>
> I thought you were inferring that the electrical changes were not sufficient
> to have an effect that could be described as significant.
>
> geoff
>
>

You thought wrong then.

Cheers

Ian

[Ian Bell[_2_]]

geoff wrote:
> Ian Bell wrote:
>
>>
>> Well, if you want to throw mechanical resonances into the pot as well
>> that's fine by me.
>
> Throw them into the pot ? They were always the 90% of the pot content.
>
> geoff
>
>


No, they only just got mentioned.

Cheers

Ian

[Ian Bell[_2_]]

geoff wrote:
> Ian Bell wrote:
>
>> And I have asked you to specify exactly how those measurements were
>> made.
>
>
> When I did it I :
> 1 - Put a loaded '57 into one channel.
> 2 - Put an unloaded one into the next channel.
> 3 - Matched the record levels.
> 4 - Recorded a sharp percussive impulse (clicking a pair of drumsticks) in a
> moderately dead acoustic.
> 5 - Looked at the result in Sound Forge.


And what WAS| the result?


Cheers

Ian

>
> I didn't do the EQ thing, because the visual (and audible) difference was so
> obvious - the nature of that difference would not have been alterred by a
> few dB of treble EQ.
>
> Try it. It should take far less time than you've spent typing here.
>
> geoff
>
>

[Geoff]

Ian Bell wrote:
> geoff wrote:
>> Ian Bell wrote:
>>
>>> And I have asked you to specify exactly how those measurements were
>>> made.
>>
>>
>> When I did it I :
>> 1 - Put a loaded '57 into one channel.
>> 2 - Put an unloaded one into the next channel.
>> 3 - Matched the record levels.
>> 4 - Recorded a sharp percussive impulse (clicking a pair of
>> drumsticks) in a moderately dead acoustic.
>> 5 - Looked at the result in Sound Forge.
>
>
> And what WAS| the result?

Pretty much similar to what Scott describes. Visible 'ringing' on the 57
running straight into a 1K5 input. Not there (or much reduced, down into the
noise level) on the 'damped' unit. A difference clearly audible on playback,
though not compared 'blind'.

geoff

[Les Cargill[_2_]]

Mike Rivers wrote:
> Ian Bell wrote:
>
>> Looking at Shure's own data sheet all it says is:
>>
>> "Rated impedance is 150Ω (310Ω actual) for connection to
>> microphone inputs rated low impedance"
>
> Now what in the world does THAT mean? Sounds like it came from
> a spec sheet. Oh . . . never mind.
>
>
>>> [Scott] I have, as I said, made some basic qualitative measurements
>>> showing
>>> ringing. If you want to do a full impulse response, I'd love to see it.
>
>> And I have asked you to specify exactly how those measurements were made.
>
> I suppose you could connect the outputs of the mic to an oscilloscope
> (or a DAW,
> for an easier look-later picture), fire a pistol in front of it, and
> look at the decay part
> of the waveform with various loads.


There's always the spark gap generator. Hack a camera flash,
and record both the spark ( make a simple
loop pickup) and the output from the mic,
then deconvolve.

--
Les Cargill

[Les Cargill[_2_]]

geoff wrote:
> Ian Bell wrote:
>
>> And I have asked you to specify exactly how those measurements were
>> made.
>
>
> When I did it I :
> 1 - Put a loaded '57 into one channel.
> 2 - Put an unloaded one into the next channel.
> 3 - Matched the record levels.
> 4 - Recorded a sharp percussive impulse (clicking a pair of drumsticks) in a
> moderately dead acoustic.
> 5 - Looked at the result in Sound Forge.
>
> I didn't do the EQ thing, because the visual (and audible) difference was so
> obvious - the nature of that difference would not have been alterred by a
> few dB of treble EQ.
>
> Try it. It should take far less time than you've spent typing here.
>
> geoff
>
>


Geoff, Voxengo offers a free deconvolver for windows. Or you can use
Octave if not Matlab.

--
Les Cargill

[Les Cargill[_2_]]

David Aguilera wrote:
> drichard wrote:
>> I don't consider it a bad thing. The discussion seems mostly civil,
>> and to me it seems enlightening. The difference between an EQ change
>> and a change in the damping is worth discussing.
>>
>
> I'm just happy to get all of this information from what I previously
> thought was a much simpler question.

It would be really cool to get Malcolm Gladwell interested in
fallacies about music equipment.

--
Les Cargill

[PStamler]

On Nov 11, 1:56Â*pm, Ian Bell > wrote:
> Scott Dorsey wrote:
> > Ian Bell > wrote:
> >> Scott Dorsey wrote:
> >>> Ian Bell > wrote:
> >>>> Well, if you want to throw mechanical resonances into the pot as well
> >>>> that's fine by me. However, dynamic mic manufacturers aim to get the
> >>>> main resonance as low as possible because the response drops like a
> >>>> stone below it - they aim for as much of the response as possible to be
> >>>> above resonance. Â*Looking at the SM57 frequency response it clearly
> >>>> drops off steeply below 200Hz so my guess it that is where the main
> >>>> resonance is.
> >>> If the mike is loaded properly, yes. Â*The response plots that you see
> >>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
> >>> the like).
> >> Are you certain. Looking at Shure's own data sheet all it says is:
>
> >> "Rated impedance is 150Ω (310Ω actual) for connection to
> >> microphone inputs rated low impedance"
>
> >> There is no mention at all of the test cinditions under which frequency
> >> response is measured.
>
> > That's true, and that's why all the confusion has occurred over the years.
> > But you'd expect that the companion mike mixer that Shure sold at the
> > time, for instance, would be a good match for it.
>
> > "Low impedance" would be something in the 500-600 ohm region. Â*Olsen's
> > book has a good description of how bridging loads on microphones work.
> > --scott
>
> The strange thing is, the Shure spec says 'rated impedance' 150R (actual
> 310R) which would result in a 3.6dB loss into a 600R load - then again
> they were never intended for very quiet sounds ;-)

And about 1.25dB loss into a 2k load. So the level into 600 ohms is
about 2.35dB lower than into 2k. Like I said, ya gotta match the
levels carefully.

[Mike Rivers]

Les Cargill wrote:

> There's always the spark gap generator. Hack a camera flash,
> and record both the spark ( make a simple
> loop pickup) and the output from the mic,
> then deconvolve.

You make it sound so simple. Go for it!

[Mike Rivers]

PStamler wrote:

>> The strange thing is, the Shure spec says 'rated impedance' 150R (actual
>> 310R) which would result in a 3.6dB loss into a 600R load - then again
>> they were never intended for very quiet sounds ;-)

> And about 1.25dB loss into a 2k load. So the level into 600 ohms is
> about 2.35dB lower than into 2k. Like I said, ya gotta match the
> levels carefully.

Or just set the gain right. But then, systems have less gain (not counting
the power amplifier) than they used to. Does anyone have any comparable
measurements on, say, a Shure VocalMaster? My VocalMaster brochure
simply says (for the "professional" model with the XLR connectors):

"Input Impedance: Suitable for microphones having an impedance of 50 to
600 ohms."

[Scott Dorsey]

Les Cargill > wrote:
>
>Geoff, Voxengo offers a free deconvolver for windows. Or you can use
>Octave if not Matlab.

Octave is one hell of a powerful tool for doing this kind of thing. It
would be my first choice if I were going to enter the 21st century...
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Les Cargill[_2_]]

Mike Rivers wrote:
> Les Cargill wrote:
>
>> There's always the spark gap generator. Hack a camera flash,
>> and record both the spark ( make a simple
>> loop pickup) and the output from the mic,
>> then deconvolve.
>
> You make it sound so simple. Go for it!

But of *course* I make it *sound* simple :)

--
Les Cargill

[Les Cargill[_2_]]

Scott Dorsey wrote:
> Les Cargill > wrote:
>> Geoff, Voxengo offers a free deconvolver for windows. Or you can use
>> Octave if not Matlab.
>
> Octave is one hell of a powerful tool for doing this kind of thing. It
> would be my first choice if I were going to enter the 21st century...
> --scott
>


It's very, very nice.

--
Les Cargill

[hank alrich]

Ian Bell > wrote:

> zero wrote:
> > "Ian Bell" > wrote in message
> > ...
> >> geoff wrote:
> >>> Ian Bell wrote:
> >
> >> No, all you said was changing the loading makes a difference. I am not
> >> disputing that.
> >
> > Ian,
> >
> > What you appear to be saying, is applying EQ can produce
> > the same results.
> >
> > Ok then. Loading a 1/4 ton in the back of your
> > pick-up truck will change the behavior of the suspension
> > in a way that air shocks and an air-ride chair will clearly
> > NOT make you feel the truck is now without weight.
> >
> > The 1/4 ton is the parallel resistor, the air-ride &
> > air-seat are your EQ. You can't simulate a 1/4 ton
> > of load, without a 1/4 ton of real load. Nor can you
> > eliminate it.
> >
>
> I am saying the Q is already low so there's already a 1/4 ton weight
> bar a few pounds loaded on the truck and when you add the parallel
> resistor its like adding just a few more pounds. You will not notice the
> difference in ride.

when you gonna get over speculating and try it? you gonna keep telling
people who've ridden in the buggy what the ride is like when you haven't
ridden in the buggy?

ain't one thing scientific about your take on this so far, in spite of
your insistence on measurements.

> Cheers
>
> ian
>
> > Say you have the perfect photo of person/object, and the
> > deal breaker is the background or foreground lighting,
> > do you fix the lighting,,, or fix the picture in Photoshop?
> > (btw, I know of no EQ/plug-in that can function as remotely close
> > in audio, as a photo-editing software does with regards
> > to pictures.)
> >
> > So. As to what says you.
> >
> > Now, I can take the stock crossover in
> > my one 15" Tannoy, add or remove components, and
> > then simply patch an EQ into it, to match the
> > other 15" Tannoy? ...Really? :-P
> >
> > --
> > -zero
> >
> >
> >


--
ha
shut up and play your guitar

[hank alrich]

Ian Bell > wrote:

> hank alrich wrote:
> > Ian Bell > wrote:
> >
> >> Mike Rivers wrote:
> >>> Ian Bell wrote:
> >>>
> >>>> All we have so far is subjective statements. No one has made any
> >>>> measurements.
> >>> Including you. Unless you've tried "the magic load" you can't
> >>> even subjectively say that you can duplicate the results with
> >>> equalization.
> >>>
> >>> I understand, though, that you like to argue and debate. We all
> >>> do, around here. We have no lives. It's what we do.
> >>
> >> I think the term 'magic load' you used sums it up. I really am not
> >> enamoured of these simple changes that 'work magic' in a purely
> >> subjective way. I much prefer to understand why and how the effect is
> >> produced but that unfortunately demotes from magic to mere science.
> >>
> >> Cheers
> >>
> >> Ian
> >
> > Figuring out why the effect results from a change in load in no way
> > negates the outright sonic MAGIC of the change.
> >
>
>
> You seriously expect sonic MAGIC from a 57?
>
> Cheers
>
> Ian

Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
not, either do it or give up the pseudo-science bull****. It's been
****ING MAGIC in well recorded and long-revered material.

I'm telling you from personal experience that given a high quality
preamp of the type for which the design was orignally intended ****ING
TERRIFIC results can be had.

--
ha
shut up and play your guitar

[Les Cargill[_2_]]

Ian Bell wrote:
> hank alrich wrote:
>> Ian Bell > wrote:
>>
>>> Mike Rivers wrote:
>>>> Ian Bell wrote:
>>>>
>>>>> All we have so far is subjective statements. No one has made any
>>>>> measurements.
>>>> Including you. Unless you've tried "the magic load" you can't
>>>> even subjectively say that you can duplicate the results with
>>>> equalization.
>>>>
>>>> I understand, though, that you like to argue and debate. We all
>>>> do, around here. We have no lives. It's what we do.
>>>
>>> I think the term 'magic load' you used sums it up. I really am not
>>> enamoured of these simple changes that 'work magic' in a purely
>>> subjective way. I much prefer to understand why and how the effect is
>>> produced but that unfortunately demotes from magic to mere science.
>>>
>>> Cheers
>>>
>>> Ian
>>
>> Figuring out why the effect results from a change in load in no way
>> negates the outright sonic MAGIC of the change.
>>
>
>
> You seriously expect sonic MAGIC from a 57?
>
> Cheers
>
> Ian


Why not? It's a great mic. It's more like an SM57 than anything
else made.

--
Les Cargill

[David Aguilera[_2_]]

Mike Rivers wrote:
> David Aguilera wrote:
>
>> I was thinking of something along the lines of this:
>> http://www.zen22142.zen.co.uk/Theory/inzoz.htm.
>
> Sure, that'll work. You're measuring the voltage drop across
> the series resistor by measuring the voltage going in and coming
> out, and using that to calculate the current since you know the
> value of the resistor. By knowing the current and the voltage
> drop across the preamp input, you can calculate the preamp's
> impedance. The half-voltage-measure-the-pot method is quicker
> as long as you have a source that's of sufficiently low impedance
> to be ignored.
>
>> I have a MOTU 896HD and would use Logic 9's utilities for a generator.
>
> I suppose that would work. You can measure the impedance of the
> generator too, and throw that into your calculation if you want a better
> answer.

Thanks for all your help.

[David Aguilera[_2_]]

Ian Bell wrote:
> Scott Dorsey wrote:
>> Ian Bell > wrote:
>>> Scott Dorsey wrote:
>>>> Ian Bell > wrote:
>>>>> Well, if you want to throw mechanical resonances into the pot as
>>>>> well that's fine by me. However, dynamic mic manufacturers aim to
>>>>> get the main resonance as low as possible because the response
>>>>> drops like a stone below it - they aim for as much of the response
>>>>> as possible to be above resonance. Looking at the SM57 frequency
>>>>> response it clearly drops off steeply below 200Hz so my guess it
>>>>> that is where the main resonance is.
>>>> If the mike is loaded properly, yes. The response plots that you see
>>>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
>>>> the like).
>>> Are you certain. Looking at Shure's own data sheet all it says is:
>>>
>>> "Rated impedance is 150Ω (310Ω actual) for connection to
>>> microphone inputs rated low impedance"
>>>
>>> There is no mention at all of the test cinditions under which
>>> frequency response is measured.
>>
>> That's true, and that's why all the confusion has occurred over the
>> years.
>> But you'd expect that the companion mike mixer that Shure sold at the
>> time, for instance, would be a good match for it.
>>
>> "Low impedance" would be something in the 500-600 ohm region. Olsen's
>> book has a good description of how bridging loads on microphones work.
>> --scott
>>
>
> The strange thing is, the Shure spec says 'rated impedance' 150R (actual
> 310R) which would result in a 3.6dB loss into a 600R load - then again
> they were never intended for very quiet sounds ;-)
>
> Cheers
>
> Ian

I noticed my 635a is also 150R. How do you make that calculation?

[Don Pearce[_3_]]

On Fri, 13 Nov 2009 07:56:34 -0700, David Aguilera
> wrote:

>Ian Bell wrote:
>> Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Scott Dorsey wrote:
>>>>> Ian Bell > wrote:
>>>>>> Well, if you want to throw mechanical resonances into the pot as
>>>>>> well that's fine by me. However, dynamic mic manufacturers aim to
>>>>>> get the main resonance as low as possible because the response
>>>>>> drops like a stone below it - they aim for as much of the response
>>>>>> as possible to be above resonance. Looking at the SM57 frequency
>>>>>> response it clearly drops off steeply below 200Hz so my guess it
>>>>>> that is where the main resonance is.
>>>>> If the mike is loaded properly, yes. The response plots that you see
>>>>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
>>>>> the like).
>>>> Are you certain. Looking at Shure's own data sheet all it says is:
>>>>
>>>> "Rated impedance is 150Ω (310Ω actual) for connection to
>>>> microphone inputs rated low impedance"
>>>>
>>>> There is no mention at all of the test cinditions under which
>>>> frequency response is measured.
>>>
>>> That's true, and that's why all the confusion has occurred over the
>>> years.
>>> But you'd expect that the companion mike mixer that Shure sold at the
>>> time, for instance, would be a good match for it.
>>>
>>> "Low impedance" would be something in the 500-600 ohm region. Olsen's
>>> book has a good description of how bridging loads on microphones work.
>>> --scott
>>>
>>
>> The strange thing is, the Shure spec says 'rated impedance' 150R (actual
>> 310R) which would result in a 3.6dB loss into a 600R load - then again
>> they were never intended for very quiet sounds ;-)
>>
>> Cheers
>>
>> Ian
>
>I noticed my 635a is also 150R. How do you make that calculation?

At 150 ohms, it is actually only 1.9dB of loss. The calculation is

20 log (600/(600+150))

310 ohms comes out at 3.6dB

You can paste that straight into Google

d

[David Aguilera[_2_]]

Ian Bell wrote:
> Scott Dorsey wrote:
>> drichard > wrote:
>>> Question for all: Doesn't the level change as well, when using the
>>> shunt resistor?
>>
>> Yes, and so the S/N is reduced a little. A better way to do this is
>> to use a step-up transformer, which gets you proper loading without
>> losing signal. Problem is, good transformers are expensive, and
>> resistors are cheap. You pays your money and you takes your chance.
>>
>
> Er, maybe I am missing something again, but is that not the purpose of
> the step up transformer built into the 57??
>
> Cheers
>
> Ian
>
>> A good transformer input preamp like the John Hardy is going to give
>> you a lower noise floor than a Mackie with a shunt resistor, and the
>> tone won't change when you adjust the gains like it does on the Mackie
>> either. But you can buy a lot of channels of Mackie for the cost of
>> one channel of the John Hardy. Life's just like that.
>> --scott
>>

I believe that is the idea here: http://www.mercenary.com/smmiwitatr.html

[David Aguilera[_2_]]

Ian Bell wrote:
> Scott Dorsey wrote:
>> drichard > wrote:
>>> Question for all: Doesn't the level change as well, when using the
>>> shunt resistor?
>>
>> Yes, and so the S/N is reduced a little. A better way to do this is
>> to use a step-up transformer, which gets you proper loading without
>> losing signal. Problem is, good transformers are expensive, and
>> resistors are cheap. You pays your money and you takes your chance.
>>
>
> Er, maybe I am missing something again, but is that not the purpose of
> the step up transformer built into the 57??
>
> Cheers
>
> Ian
>
>> A good transformer input preamp like the John Hardy is going to give
>> you a lower noise floor than a Mackie with a shunt resistor, and the
>> tone won't change when you adjust the gains like it does on the Mackie
>> either. But you can buy a lot of channels of Mackie for the cost of
>> one channel of the John Hardy. Life's just like that.
>> --scott
>>

I believe that is the idea here:
http://www.mercenary.com/smmiwitatr.html. Right?

[David Aguilera[_2_]]

Ian Bell wrote:
> Scott Dorsey wrote:
>> Ian Bell > wrote:
>>> No, that's quite enough for me. I am just glad someone actually made
>>> some real measurements.
>>
>> But I _didn't_ do it with the transformer removed.
>
>
> But most folk will use it with the transformer installed will they not.
>
> Cheers
>
> Ian
> There's still a chance
>> that what I was seeing was resulting from the transformer issues. I
>> don't think
>> it was, but I didn't test for it.
>> --scott

I assume so. I belive you have to boil the mic body to remove the
transformer. I saw a bunch on hot glue gun gunk in there when I
resoldered to XLR connector on one.

[David Aguilera[_2_]]

Don Pearce wrote:
> On Fri, 13 Nov 2009 07:56:34 -0700, David Aguilera
> > wrote:
>
>> Ian Bell wrote:
>>> Scott Dorsey wrote:
>>>> Ian Bell > wrote:
>>>>> Scott Dorsey wrote:
>>>>>> Ian Bell > wrote:
>>>>>>> Well, if you want to throw mechanical resonances into the pot as
>>>>>>> well that's fine by me. However, dynamic mic manufacturers aim to
>>>>>>> get the main resonance as low as possible because the response
>>>>>>> drops like a stone below it - they aim for as much of the response
>>>>>>> as possible to be above resonance. Looking at the SM57 frequency
>>>>>>> response it clearly drops off steeply below 200Hz so my guess it
>>>>>>> that is where the main resonance is.
>>>>>> If the mike is loaded properly, yes. The response plots that you see
>>>>>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
>>>>>> the like).
>>>>> Are you certain. Looking at Shure's own data sheet all it says is:
>>>>>
>>>>> "Rated impedance is 150Ω (310Ω actual) for connection to
>>>>> microphone inputs rated low impedance"
>>>>>
>>>>> There is no mention at all of the test cinditions under which
>>>>> frequency response is measured.
>>>> That's true, and that's why all the confusion has occurred over the
>>>> years.
>>>> But you'd expect that the companion mike mixer that Shure sold at the
>>>> time, for instance, would be a good match for it.
>>>>
>>>> "Low impedance" would be something in the 500-600 ohm region. Olsen's
>>>> book has a good description of how bridging loads on microphones work.
>>>> --scott
>>>>
>>> The strange thing is, the Shure spec says 'rated impedance' 150R (actual
>>> 310R) which would result in a 3.6dB loss into a 600R load - then again
>>> they were never intended for very quiet sounds ;-)
>>>
>>> Cheers
>>>
>>> Ian
>> I noticed my 635a is also 150R. How do you make that calculation?
>
> At 150 ohms, it is actually only 1.9dB of loss. The calculation is
>
> 20 log (600/(600+150))
>
> 310 ohms comes out at 3.6dB
>
> You can paste that straight into Google
>
> d

Thanks!

[Mike Rivers]

David Aguilera wrote:

> I noticed my 635a is also 150R. How do you make that calculation?

It used to be that if there was a specification for a microphone's impedance
at all, it was usually just stated as a single number like that, with no
mention
of how it was measured, at what frequency, and just what it was. I would
assume that it's the mic's source impedance measured at a frequency well
away from any resonances that would affect the impedance measurement.

These days, if a microphone spec sheet says anything about impedance,
it's usually along the lines of "Works best into a preamp with an input
impedance of 1800 ohms or greater." [substitute the appropriate number]

It's interesting to note that the Gordon preamp, which is perhaps the
world's most expensive non-vintage one, and what many thing is the
best sounding one, has a very high, like a couple of megohms, input
impedance. I guess he figures that, for better or worse, that gives you
the most accurate representation of what comes out of the mic, and you
can take it from there.

[Anahata]

On Fri, 13 Nov 2009 11:42:57 -0500, Mike Rivers wrote:

>
> It's interesting to note that the Gordon preamp...
> has a very high, like a couple of megohms, input
> impedance.

But also that it has a switch to lower the input impedance to 1k.

--
Anahata
-+- http://www.treewind.co.uk
Home: 01638 720444 Mob: 07976 263827

[hank alrich]

Anahata > wrote:

> On Fri, 13 Nov 2009 11:42:57 -0500, Mike Rivers wrote:
>
> >
> > It's interesting to note that the Gordon preamp...
> > has a very high, like a couple of megohms, input
> > impedance.
>
> But also that it has a switch to lower the input impedance to 1k.

My "wish I hade one of those preamps" list is very short in my old age:

Gordon
Great River MP2-NV

--
ha
shut up and play your guitar

[Scott Dorsey]

David Aguilera > wrote:
>
>I assume so. I belive you have to boil the mic body to remove the
>transformer. I saw a bunch on hot glue gun gunk in there when I
>resoldered to XLR connector on one.

You don't have the actually remove it, you can disconnect the element
instead and wire to that. That's easier.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[david correia]

In article >,
(hank alrich) wrote:

> Ian Bell > wrote:
>
> > hank alrich wrote:
> > > Ian Bell > wrote:
> > >
> > >> Mike Rivers wrote:
> > >>> Ian Bell wrote:
> > >>>
> > >>>> All we have so far is subjective statements. No one has made any
> > >>>> measurements.
> > >>> Including you. Unless you've tried "the magic load" you can't
> > >>> even subjectively say that you can duplicate the results with
> > >>> equalization.
> > >>>
> > >>> I understand, though, that you like to argue and debate. We all
> > >>> do, around here. We have no lives. It's what we do.
> > >>
> > >> I think the term 'magic load' you used sums it up. I really am not
> > >> enamoured of these simple changes that 'work magic' in a purely
> > >> subjective way. I much prefer to understand why and how the effect is
> > >> produced but that unfortunately demotes from magic to mere science.
> > >>
> > >> Cheers
> > >>
> > >> Ian
> > >
> > > Figuring out why the effect results from a change in load in no way
> > > negates the outright sonic MAGIC of the change.
> > >
> >
> >
> > You seriously expect sonic MAGIC from a 57?
> >
> > Cheers
> >
> > Ian
>
> Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
> not, either do it or give up the pseudo-science bull****. It's been
> ****ING MAGIC in well recorded and long-revered material.
>
> I'm telling you from personal experience that given a high quality
> preamp of the type for which the design was orignally intended ****ING
> TERRIFIC results can be had.
>
> --
> ha
> shut up and play your guitar




I gotta say, I too have gotten plenty of sonic magic from a 57. Tons.
For decades.

I like it, love it, yes I do ;>




David Correia
www.Celebrationsound.com

[Ian Bell[_2_]]

David Aguilera wrote:
> Ian Bell wrote:
>> Scott Dorsey wrote:
>>> Ian Bell > wrote:
>>>> Scott Dorsey wrote:
>>>>> Ian Bell > wrote:
>>>>>> Well, if you want to throw mechanical resonances into the pot as
>>>>>> well that's fine by me. However, dynamic mic manufacturers aim to
>>>>>> get the main resonance as low as possible because the response
>>>>>> drops like a stone below it - they aim for as much of the response
>>>>>> as possible to be above resonance. Looking at the SM57 frequency
>>>>>> response it clearly drops off steeply below 200Hz so my guess it
>>>>>> that is where the main resonance is.
>>>>> If the mike is loaded properly, yes. The response plots that you see
>>>>> on the data sheet are assuming about a 600 ohm load (Shure M67 or
>>>>> the like).
>>>> Are you certain. Looking at Shure's own data sheet all it says is:
>>>>
>>>> "Rated impedance is 150Ω (310Ω actual) for connection to
>>>> microphone inputs rated low impedance"
>>>>
>>>> There is no mention at all of the test cinditions under which
>>>> frequency response is measured.
>>>
>>> That's true, and that's why all the confusion has occurred over the
>>> years.
>>> But you'd expect that the companion mike mixer that Shure sold at the
>>> time, for instance, would be a good match for it.
>>>
>>> "Low impedance" would be something in the 500-600 ohm region. Olsen's
>>> book has a good description of how bridging loads on microphones work.
>>> --scott
>>>
>>
>> The strange thing is, the Shure spec says 'rated impedance' 150R
>> (actual 310R) which would result in a 3.6dB loss into a 600R load -
>> then again they were never intended for very quiet sounds ;-)
>>
>> Cheers
>>
>> Ian
>
> I noticed my 635a is also 150R. How do you make that calculation?

It is 20*log(Rpre/(Rpre+Rmic))

where Rpre is the mic pre input resistance and Rmic is the mic source
resistance.

Cheers

Ian

[Ian Bell[_2_]]

david correia wrote:
> In article >,
> (hank alrich) wrote:
>
>> Ian Bell > wrote:
>>
>>> hank alrich wrote:
>>>> Ian Bell > wrote:
>>>>
>>>>> Mike Rivers wrote:
>>>>>> Ian Bell wrote:
>>>>>>
>>>>>>> All we have so far is subjective statements. No one has made any
>>>>>>> measurements.
>>>>>> Including you. Unless you've tried "the magic load" you can't
>>>>>> even subjectively say that you can duplicate the results with
>>>>>> equalization.
>>>>>>
>>>>>> I understand, though, that you like to argue and debate. We all
>>>>>> do, around here. We have no lives. It's what we do.
>>>>> I think the term 'magic load' you used sums it up. I really am not
>>>>> enamoured of these simple changes that 'work magic' in a purely
>>>>> subjective way. I much prefer to understand why and how the effect is
>>>>> produced but that unfortunately demotes from magic to mere science.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Ian
>>>> Figuring out why the effect results from a change in load in no way
>>>> negates the outright sonic MAGIC of the change.
>>>>
>>>
>>> You seriously expect sonic MAGIC from a 57?
>>>
>>> Cheers
>>>
>>> Ian
>> Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
>> not, either do it or give up the pseudo-science bull****. It's been
>> ****ING MAGIC in well recorded and long-revered material.
>>
>> I'm telling you from personal experience that given a high quality
>> preamp of the type for which the design was orignally intended ****ING
>> TERRIFIC results can be had.
>>
>> --
>> ha
>> shut up and play your guitar
>
>
>
>
> I gotta say, I too have gotten plenty of sonic magic from a 57. Tons.
> For decades.
>
> I like it, love it, yes I do ;>
>
>

This may be one of those US/UK divide things. I think the SM57 sounds
like the cheap ****e PA vocal mic it was intended to be.

Cheers

ian
>
>
> David Correia
> www.Celebrationsound.com

[Scott Dorsey]

Ian Bell > wrote:
>
>This may be one of those US/UK divide things. I think the SM57 sounds
>like the cheap ****e PA vocal mic it was intended to be.

Try it with the shunt. It still has the huge dominant presence peak,
but the artificially harsh stuff on top goes away.

I wouldn't call it "magic" myself, but there are times when you want
that presence effect, and the SM-57 does it splendidly.
---scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[hank alrich]

Ian Bell > wrote:

> david correia wrote:
> > In article >,
> > (hank alrich) wrote:
> >
> >> Ian Bell > wrote:
> >>
> >>> hank alrich wrote:
> >>>> Ian Bell > wrote:
> >>>>
> >>>>> Mike Rivers wrote:
> >>>>>> Ian Bell wrote:
> >>>>>>
> >>>>>>> All we have so far is subjective statements. No one has made any
> >>>>>>> measurements.
> >>>>>> Including you. Unless you've tried "the magic load" you can't
> >>>>>> even subjectively say that you can duplicate the results with
> >>>>>> equalization.
> >>>>>>
> >>>>>> I understand, though, that you like to argue and debate. We all
> >>>>>> do, around here. We have no lives. It's what we do.
> >>>>> I think the term 'magic load' you used sums it up. I really am not
> >>>>> enamoured of these simple changes that 'work magic' in a purely
> >>>>> subjective way. I much prefer to understand why and how the effect is
> >>>>> produced but that unfortunately demotes from magic to mere science.
> >>>>>
> >>>>> Cheers
> >>>>>
> >>>>> Ian
> >>>> Figuring out why the effect results from a change in load in no way
> >>>> negates the outright sonic MAGIC of the change.
> >>>>
> >>>
> >>> You seriously expect sonic MAGIC from a 57?
> >>>
> >>> Cheers
> >>>
> >>> Ian
> >> Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
> >> not, either do it or give up the pseudo-science bull****. It's been
> >> ****ING MAGIC in well recorded and long-revered material.
> >>
> >> I'm telling you from personal experience that given a high quality
> >> preamp of the type for which the design was orignally intended ****ING
> >> TERRIFIC results can be had.
> >>
> >> --
> >> ha
> >> shut up and play your guitar
> >
> >
> >
> >
> > I gotta say, I too have gotten plenty of sonic magic from a 57. Tons.
> > For decades.
> >
> > I like it, love it, yes I do ;>
> >
> >
>
> This may be one of those US/UK divide things. I think the SM57 sounds
> like the cheap ****e PA vocal mic it was intended to be.

Ever hooked one up to Big Iron?

--
ha
shut up and play your guitar

[Les Cargill[_2_]]

David Aguilera wrote:
> Ian Bell wrote:
>> Scott Dorsey wrote:
>>> drichard > wrote:
>>>> Question for all: Doesn't the level change as well, when using the
>>>> shunt resistor?
>>>
>>> Yes, and so the S/N is reduced a little. A better way to do this is
>>> to use a step-up transformer, which gets you proper loading without
>>> losing signal. Problem is, good transformers are expensive, and
>>> resistors are cheap. You pays your money and you takes your chance.
>>>
>>
>> Er, maybe I am missing something again, but is that not the purpose of
>> the step up transformer built into the 57??
>>
>> Cheers
>>
>> Ian
>>
>>> A good transformer input preamp like the John Hardy is going to give
>>> you a lower noise floor than a Mackie with a shunt resistor, and the
>>> tone won't change when you adjust the gains like it does on the Mackie
>>> either. But you can buy a lot of channels of Mackie for the cost of
>>> one channel of the John Hardy. Life's just like that.
>>> --scott
>>>
>
> I believe that is the idea here: http://www.mercenary.com/smmiwitatr.html


yes, but it's not just a microphone. It's also a filter ( without
the fancy xformer )....

--
Les Cargill

[Ian Bell[_2_]]

hank alrich wrote:
> Ian Bell > wrote:
>
>> david correia wrote:
>>> In article >,
>>> (hank alrich) wrote:
>>>
>>>> Ian Bell > wrote:
>>>>
>>>>> hank alrich wrote:
>>>>>> Ian Bell > wrote:
>>>>>>
>>>>>>> Mike Rivers wrote:
>>>>>>>> Ian Bell wrote:
>>>>>>>>
>>>>>>>>> All we have so far is subjective statements. No one has made any
>>>>>>>>> measurements.
>>>>>>>> Including you. Unless you've tried "the magic load" you can't
>>>>>>>> even subjectively say that you can duplicate the results with
>>>>>>>> equalization.
>>>>>>>>
>>>>>>>> I understand, though, that you like to argue and debate. We all
>>>>>>>> do, around here. We have no lives. It's what we do.
>>>>>>> I think the term 'magic load' you used sums it up. I really am not
>>>>>>> enamoured of these simple changes that 'work magic' in a purely
>>>>>>> subjective way. I much prefer to understand why and how the effect is
>>>>>>> produced but that unfortunately demotes from magic to mere science.
>>>>>>>
>>>>>>> Cheers
>>>>>>>
>>>>>>> Ian
>>>>>> Figuring out why the effect results from a change in load in no way
>>>>>> negates the outright sonic MAGIC of the change.
>>>>>>
>>>>> You seriously expect sonic MAGIC from a 57?
>>>>>
>>>>> Cheers
>>>>>
>>>>> Ian
>>>> Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
>>>> not, either do it or give up the pseudo-science bull****. It's been
>>>> ****ING MAGIC in well recorded and long-revered material.
>>>>
>>>> I'm telling you from personal experience that given a high quality
>>>> preamp of the type for which the design was orignally intended ****ING
>>>> TERRIFIC results can be had.
>>>>
>>>> --
>>>> ha
>>>> shut up and play your guitar
>>>
>>>
>>>
>>> I gotta say, I too have gotten plenty of sonic magic from a 57. Tons.
>>> For decades.
>>>
>>> I like it, love it, yes I do ;>
>>>
>>>
>> This may be one of those US/UK divide things. I think the SM57 sounds
>> like the cheap ****e PA vocal mic it was intended to be.
>
> Ever hooked one up to Big Iron?
>


Yup, saw and heard them hooked up to many a Neve when I worked there in
the 70s.

Cheers

ian

[hank alrich]

Ian Bell > wrote:

> hank alrich wrote:
> > Ian Bell > wrote:
> >
> >> david correia wrote:
> >>> In article >,
> >>> (hank alrich) wrote:
> >>>
> >>>> Ian Bell > wrote:
> >>>>
> >>>>> hank alrich wrote:
> >>>>>> Ian Bell > wrote:
> >>>>>>
> >>>>>>> Mike Rivers wrote:
> >>>>>>>> Ian Bell wrote:
> >>>>>>>>
> >>>>>>>>> All we have so far is subjective statements. No one has made any
> >>>>>>>>> measurements.
> >>>>>>>> Including you. Unless you've tried "the magic load" you can't
> >>>>>>>> even subjectively say that you can duplicate the results with
> >>>>>>>> equalization.
> >>>>>>>>
> >>>>>>>> I understand, though, that you like to argue and debate. We all
> >>>>>>>> do, around here. We have no lives. It's what we do.
> >>>>>>> I think the term 'magic load' you used sums it up. I really am not
> >>>>>>> enamoured of these simple changes that 'work magic' in a purely
> >>>>>>> subjective way. I much prefer to understand why and how the effect is
> >>>>>>> produced but that unfortunately demotes from magic to mere science.
> >>>>>>>
> >>>>>>> Cheers
> >>>>>>>
> >>>>>>> Ian
> >>>>>> Figuring out why the effect results from a change in load in no way
> >>>>>> negates the outright sonic MAGIC of the change.
> >>>>>>
> >>>>> You seriously expect sonic MAGIC from a 57?
> >>>>>
> >>>>> Cheers
> >>>>>
> >>>>> Ian
> >>>> Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
> >>>> not, either do it or give up the pseudo-science bull****. It's been
> >>>> ****ING MAGIC in well recorded and long-revered material.
> >>>>
> >>>> I'm telling you from personal experience that given a high quality
> >>>> preamp of the type for which the design was orignally intended ****ING
> >>>> TERRIFIC results can be had.
> >>>>
> >>>> --
> >>>> ha
> >>>> shut up and play your guitar
> >>>
> >>>
> >>>
> >>> I gotta say, I too have gotten plenty of sonic magic from a 57. Tons.
> >>> For decades.
> >>>
> >>> I like it, love it, yes I do ;>
> >>>
> >>>
> >> This may be one of those US/UK divide things. I think the SM57 sounds
> >> like the cheap ****e PA vocal mic it was intended to be.
> >
> > Ever hooked one up to Big Iron?
> >
>
>
> Yup, saw and heard them hooked up to many a Neve when I worked there in
> the 70s.
>
> Cheers
>
> ian

I like 'em for some things when they're connected to that kind of
preamp.

--
ha
shut up and play your guitar

[david correia]

In article >,
Ian Bell > wrote:

> david correia wrote:
> > In article >,
> > (hank alrich) wrote:
> >
> >> Ian Bell > wrote:
> >>
> >>> hank alrich wrote:
> >>>> Ian Bell > wrote:
> >>>>
> >>>>> Mike Rivers wrote:
> >>>>>> Ian Bell wrote:
> >>>>>>
> >>>>>>> All we have so far is subjective statements. No one has made any
> >>>>>>> measurements.
> >>>>>> Including you. Unless you've tried "the magic load" you can't
> >>>>>> even subjectively say that you can duplicate the results with
> >>>>>> equalization.
> >>>>>>
> >>>>>> I understand, though, that you like to argue and debate. We all
> >>>>>> do, around here. We have no lives. It's what we do.
> >>>>> I think the term 'magic load' you used sums it up. I really am not
> >>>>> enamoured of these simple changes that 'work magic' in a purely
> >>>>> subjective way. I much prefer to understand why and how the effect is
> >>>>> produced but that unfortunately demotes from magic to mere science.
> >>>>>
> >>>>> Cheers
> >>>>>
> >>>>> Ian
> >>>> Figuring out why the effect results from a change in load in no way
> >>>> negates the outright sonic MAGIC of the change.
> >>>>
> >>>
> >>> You seriously expect sonic MAGIC from a 57?
> >>>
> >>> Cheers
> >>>
> >>> Ian
> >> Ever mic'd a good snare drum with a 57 feeding an API 312 or 512? If
> >> not, either do it or give up the pseudo-science bull****. It's been
> >> ****ING MAGIC in well recorded and long-revered material.
> >>
> >> I'm telling you from personal experience that given a high quality
> >> preamp of the type for which the design was orignally intended ****ING
> >> TERRIFIC results can be had.
> >>
> >> --
> >> ha
> >> shut up and play your guitar
> >
> >
> >
> >
> > I gotta say, I too have gotten plenty of sonic magic from a 57. Tons.
> > For decades.
> >
> > I like it, love it, yes I do ;>
> >
> >
>
> This may be one of those US/UK divide things. I think the SM57 sounds
> like the cheap ****e PA vocal mic it was intended to be.
>
> Cheers
>
> ian


Do you record rock and roll?




David Correia
www.Celebrationsound.com

[Arny Krueger]

"geoff" > wrote in message

> Ian Bell wrote:
>> geoff wrote:
>>> Ian Bell wrote:
>>>
>>>> And I have asked you to specify exactly how those
>>>> measurements were made.
>>>
>>>
>>> When I did it I :
>>> 1 - Put a loaded '57 into one channel.
>>> 2 - Put an unloaded one into the next channel.
>>> 3 - Matched the record levels.
>>> 4 - Recorded a sharp percussive impulse (clicking a
>>> pair of drumsticks) in a moderately dead acoustic.
>>> 5 - Looked at the result in Sound Forge.
>>
>>
>> And what WAS| the result?
>
> Pretty much similar to what Scott describes. Visible
> 'ringing' on the 57 running straight into a 1K5 input.
> Not there (or much reduced, down into the noise level) on
> the 'damped' unit. A difference clearly audible on
> playback, though not compared 'blind'.

Seems like a good time to post the audio files.