"Daniel Fuchs" wrote in message
...


soundhaspriority wrote:

Daniel, to the extent it applies, you are hijacking "my" thread. Would
you
please stop doing it here?

Valid point. Nevertheless, do read the info on quoting I posted.
Newsgroup etiquettes do make sense...


Daniel

Daniel, fyi, the individual who I was quoting has troubles. I wanted him to
know how much I appreciated his information.

Best,
Bob Morein

In article , "soundhaspriority"
wrote:


"Daniel Fuchs" wrote in message
...


soundhaspriority wrote:

Arny, good info.

soundhaspriority, bad post.


Daniel

Daniel, to the extent it applies, you are hijacking "my" thread. Would you
please stop doing it here?

It's a forgery by Brian L. McCarty.
Regards,
Bob Morein

soundhaspriority wrote:

Any other options I should consider? Tia,
Bob

You may want to consider getting some Avenson Audio STO-2s. They run
about $400 USD for a pair (they're only sold in sets).

-Andrew-

Daniel Fuchs wrote:

Quoting 130 lines of Arny's posting just to add one single line does not
qualify as "filing" it. Please learn to quote economically in
newsgroups.

If you want to take defensive measures and you use Thunderbird, get the
QuoteCollapse extension for reading and NestedQuoteRemover for replying.
They make lazy newsgroups much less irritating.


Bob
--

"Things should be described as simply as possible, but no simpler."

A. Einstein

wrote in message
ups.com...
soundhaspriority wrote:

Any other options I should consider? Tia,
Bob

You may want to consider getting some Avenson Audio STO-2s. They run
about $400 USD for a pair (they're only sold in sets).

-Andrew-

Very interesting. http://www.mercenary.com/sto2microphone.html They look
like an inexpensive alternative to Earthworks. But these mics have about 10
dB more self noise than typical. Although there is no sensitivity spec, I
would assume that these are noisier than typical mikes. Also, they're
electrets, not AT back electrets, but real electrets, with the greater noise
that implies. So the technology is similar to what's found in a Behringer
measurement mike, http://www.behringer.com/ECM8000/index.cfm?lang=ENG,

though the capsule is undoubtedly better. Ever make a comparison?

soundhaspriority wrote:

You may want to consider getting some Avenson Audio STO-2s.

They look
like an inexpensive alternative to Earthworks. But these mics have about 10
dB more self noise than typical.

The orignal Earthworks measurement style mics are a little on the noisy
side. They made better (quieter) models later. It comes with the
territory when you have a small diaphragm - not a lot of output for a
given SPL, so for the same voltage out of the microphone you get more
noise.

Also, they're
electrets, not AT back electrets, but real electrets, with the greater noise
that implies.

An electret is the electrostatic equivalent of a permanent magnet.
They're all real, and they're all "back." Back when manufacturers first
started to make inexpensive mics, they used electrets to save the cost
of providing a DC polarizing voltage, and at the time, all of the
electret mic capsules were cheap and crummy. There's no reason why an
electret mic capsule can't be good, it's just that the only market for
electrets at the time were in cheap mics. The Shure SM-81, which has
been around for over 25 years, has an electret capsule and it sounds
fine and is reasonably quiet for mics of that period. New ones are even
quieter.

Don't perpetuate rumors about the technology based on when product
demand was for cheap electrets.

soundhaspriority wrote:

Very interesting. http://www.mercenary.com/sto2microphone.html They look
like an inexpensive alternative to Earthworks. But these mics have about 10
dB more self noise than typical. Although there is no sensitivity spec, I
would assume that these are noisier than typical mikes.

No, they are actually quieter than the earlier Earthworks mikes. They use
very similar capsules although not the same ones.

You cannot compare self-noise numbers on the datasheets between manufactures
because there are a bunch of different standards for measuring noise. The
AES microphone standards guys are always trying to do something about this
but the manufacturers aren't cooperating.

Also, they're
electrets, not AT back electrets, but real electrets, with the greater noise
that implies.

No, they are back electrets. Front-electret capsules haven't been made
for twenty years or so, even for communications applications. And front
electret designs mainly have issues with high frequency response, due to
the high diaphragm mass, not with noise.

So the technology is similar to what's found in a Behringer
measurement mike, http://www.behringer.com/ECM8000/index.cfm?lang=ENG,

It is. The Behringer uses a back-electret capsule which is a Chinese
clone of the Japanese capsule designs used in the Earthworks and Avenson
mikes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

soundhaspriority wrote:
wrote
You may want to consider getting some Avenson Audio STO-2s. They run
about $400 USD for a pair (they're only sold in sets).

though the capsule is undoubtedly better. Ever make a comparison?

Yes, I have. The Avenson is far the better microphone. The first
Behringer I had was so noisy to be unusable. Exchanged for another,
and it was the same.

I use the Avensons on many things, very nice response. Although I've
never seen them for $400, more like $500/pair.

You could also consider EV 635a if you can use dynamic omni.

Steve

On Tue, 2 May 2006 11:20:14 -0400, soundhaspriority wrote
(in article ) :

Reiner,
That is a very interesting subject for discussion. It appears that
Chinese microphones are upsetting the established order. Whatever they are,
they are not throwaways, except for the very cheapest. In comparisons
between Neumanns and MXL's, or Studio Projects, differences are noted, but
not necessarily killing differences. Nevertheless, I appreciate your
mention, because MBHO is not well distributed here, so I was completely
unaware of them. The MBNM-622 looks interesting. Do you have any experience
with it?

You want a killer omni?
Gefell m296
or the new 100 kHz Sanken I haven't quite heard enough of.

Ty Ford



-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

Ty Ford wrote:

You want a killer omni?
Gefell m296

Yeah, rub it in, Ty... ;-)
I just decided not to buy a pair of these anytime soon, for money
reasons... Well, I have a pair of Neumann KM 131 to console myself with
for the time being... Along with my good old AKGs, that is...


Daniel

Mike Rivers wrote:


The orignal Earthworks measurement style mics are a little on the noisy
side. They made better (quieter) models later.

I had an SR 78 which was unusable as a spot mic in classical recordings
- simply too noisy for the purpose, where you'd not place it all that
close to the source. Sold it to a studio, they seem to be happy with it.
Sure it works well in front of a guitar amp.


Daniel

In article , "Scott Dorsey"
wrote:

You cannot compare self-noise numbers on the datasheets between manufactures
because there are a bunch of different standards for measuring noise. The
AES microphone standards guys are always trying to do something about this
but the manufacturers aren't cooperating.

I've read this board long enough, so now I know everything. I can read a
datasheet, and that's the only way to buy equipment - specs. I went to
college for a long time, too and clearly I'm smarter than any of you other
pro audio fools.

"soundhaspriority" is actually Robert Morein, a pest on
rec.audio.marketplace, where he accuses innocent sellers of various
misdeeds. He appears to be a pathological liar, with unknown motivations.

Morein is the owner of websites http://www.studentsandthelaw.com, which have
used fraudulent advertising in attempts to attract investors. Both have been
unsuccessful. Morein is known to associate with sexual predators and
pedophiles including Brian McCarty. Find "Brian McCarty" at this website:
http://tinyurl.com/bz2bh

Morein is an Israeli expatriate, originally from the Trenton area, where he
went to college for 12 years without any degree ever being conferred. He
then tried suing Drexel University for fraud, but the court rejected
Morein's arguments. As everyone with a lick of sense does.

Morien is currently living in his daddy's house in Dresher Pennsylvania,
where he manages to stalk a wide variety of people while swilling beer and
ogling the neighbors. He has no job. He never has. He never will.
His daddy's house is located at
1570 Arran Way
Dresher, PA

Morein lives at 1570 Arran Way, Dresher Pennsylvania,
a bit west of metropolitan Philadelphia.

Robert Morein can be contacted at

"Mike Rivers" wrote in message
oups.com...

soundhaspriority wrote:

You may want to consider getting some Avenson Audio STO-2s.

They look
like an inexpensive alternative to Earthworks. But these mics have about
10
dB more self noise than typical.

The orignal Earthworks measurement style mics are a little on the noisy
side. They made better (quieter) models later. It comes with the
territory when you have a small diaphragm - not a lot of output for a
given SPL, so for the same voltage out of the microphone you get more
noise.

Also, they're
electrets, not AT back electrets, but real electrets, with the greater
noise
that implies.

An electret is the electrostatic equivalent of a permanent magnet.
They're all real, and they're all "back." Back when manufacturers first
started to make inexpensive mics, they used electrets to save the cost
of providing a DC polarizing voltage, and at the time, all of the
electret mic capsules were cheap and crummy. There's no reason why an
electret mic capsule can't be good, it's just that the only market for
electrets at the time were in cheap mics. The Shure SM-81, which has
been around for over 25 years, has an electret capsule and it sounds
fine and is reasonably quiet for mics of that period. New ones are even
quieter.

Don't perpetuate rumors about the technology based on when product
demand was for cheap electrets.

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the best
ones can now rival capacitor mics in every respect apart from low noise..."
The article says that electrets can be made that are the equal... but also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

Noise in a condenser microphone is due to three factors:
1. Brownian motion (size of diaphram)
2. Noise figure of the FET amplifier
3. Strength of the polarization field.

The obvious candidate for the difference in noise between the best available
electrets versus the best available condenser microphones would be with
respect to factor 3.

Therefore, this is not a rumor; it is a fact that in choice of an electret,
one gives up some noise.

soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone

You can believe anything you choose to believe. You have incomplete
information. Do with it as you see fit.

Therefore, this is not a rumor; it is a fact that in choice of an electret,
one gives up some noise.

Whatever. I can find you externally polarized condenser mics that are
noisier than electret mics. Either it's a good mic or it's a poor mic.
If you design and builid your own, you can start out with whatever
capsule design you want, but while you still have to purcahse a mic,
look at the actual performance before you rule out a technology. But
then you were the one who wanted a tube mic or preamp, weren't you,
because you thought it must be better?

soundhaspriority wrote:
I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the best
ones can now rival capacitor mics in every respect apart from low noise..."

They ARE capacitor mikes.

The article says that electrets can be made that are the equal... but also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

They are. The DPA 4006 is one of the quietest things around, and it is
an electret although it doesn't advertise so on the box.

Wikipedia is... well... not really very accurate about most things.

Noise in a condenser microphone is due to three factors:
1. Brownian motion (size of diaphram)
2. Noise figure of the FET amplifier
3. Strength of the polarization field.

The obvious candidate for the difference in noise between the best available
electrets versus the best available condenser microphones would be with
respect to factor 3.

No, not at all.
You can build VERY strong electrets today.

Most electret capsules out there, and the ones that you see in the Avenson
and the older Earthworks are among them, have most of their noise coming
from the FET amplifier, because they use a nifty scheme that adds a diode
to the surface of the FET to provide a leakage path for bias. That diode
is noisy, but it makes it possible to include cheap integral amplifier stages
in the capsules.

Therefore, this is not a rumor; it is a fact that in choice of an electret,
one gives up some noise.

Not at all. Try actually listening to some mikes. Start with electret
designs like the Shure KSM-series mikes and the DPA mikes....
--scott

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

soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the best
ones can now rival capacitor mics in every respect apart from low noise..."
The article says that electrets can be made that are the equal... but also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

You obviously didn't read the item very well. It says under electrets " While
few electret microphones rival the best DC-polarized units in terms of noise
level, this is not due to any inherent limitation of the electret "

Note *few* btw. Many electrets are economy mics not designed for ultimate
performance.

Graham

soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported
by this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I
quote: Though electret mics were once considered low-cost and low quality,
the best ones can now rival capacitor mics in every respect apart from low
noise..." The article says that electrets can be made that are the
equal... but also, ARE NOT made that are the equal in terms of noise. The
article does not explain why quiet electrets cannot be made, but it quite
unequivocally states that they are not.

Do you understand that ANYBODY can write ANYTHING in Wiki? It a good
starting point for further research, but it's NOT the final word on ANY
subject.

No wonder they kicked your ass out of college.

"Mike Rivers" wrote in message
ups.com...

soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported
by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone

You can believe anything you choose to believe. You have incomplete
information. Do with it as you see fit.

Therefore, this is not a rumor; it is a fact that in choice of an
electret,
one gives up some noise.

Whatever. I can find you externally polarized condenser mics that are
noisier than electret mics.

Yes, that's true.

Either it's a good mic or it's a poor mic.
If you design and builid your own, you can start out with whatever
capsule design you want, but while you still have to purcahse a mic,
look at the actual performance before you rule out a technology.

One other thing that peeves me about electrets is the sensitivity to high
temperature. A-T warns not to expose to temperatures over 110F. This is all
too easily reached by accident during travel. While many people have boasted
that their good German mikes are still good after many years, the electret
inevitably depolarizes sooner or later.

But
then you were the one who wanted a tube mic or preamp, weren't you,
because you thought it must be better?

I thought it MIGHT be better. I take what people tell me here very
seriously. As a result of the input, I purchased an Apogee Mini-Me. There
are no tubes present in my configuration at all.

"Pooh Bear" wrote in message
...


soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported
by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the
best
ones can now rival capacitor mics in every respect apart from low
noise..."
The article says that electrets can be made that are the equal... but
also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

You obviously didn't read the item very well. It says under electrets "
While
few electret microphones rival the best DC-polarized units in terms of
noise
level, this is not due to any inherent limitation of the electret "

I did note that, and I included it in the wording of my reply.


Note *few* btw. Many electrets are economy mics not designed for ultimate
performance.

Graham

"Agent 86" wrote in message
. ..
soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported
by this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I
quote: Though electret mics were once considered low-cost and low
quality,
the best ones can now rival capacitor mics in every respect apart from
low
noise..." The article says that electrets can be made that are the
equal... but also, ARE NOT made that are the equal in terms of noise. The
article does not explain why quiet electrets cannot be made, but it quite
unequivocally states that they are not.

Do you understand that ANYBODY can write ANYTHING in Wiki? It a good
starting point for further research, but it's NOT the final word on ANY
subject.

Neither are you.

Forgery by Brian L. McCarty.

"Scott Dorsey" wrote in message
...
soundhaspriority wrote:
I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported
by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the
best
ones can now rival capacitor mics in every respect apart from low
noise..."

They ARE capacitor mikes.

The article says that electrets can be made that are the equal... but
also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

They are. The DPA 4006 is one of the quietest things around, and it is
an electret although it doesn't advertise so on the box.

They say on their website, "As DPA has developed a technology using of
prepolarized microphone capsules with a high polarization voltage, the
microphones are not dependent on the phantom power for polarization and it
is possible to obtain a large distance between the diaphragm and the
back-plate to handle the high sound pressure levels. It took several years
to develop a prepolarization concept that was so stable that it could live
up to the extreme demands of both the Bruel & Kjaer and DPA standards. But
the result was worth waiting for."

This implies that the technology used to create a strong field by the use of
electrets is not universally shared among all the maunfacturers of
electrets.

On 5/4/06 13:20, in article ,
"Agent 86" wrote:

Do you understand that ANYBODY can write ANYTHING in Wiki? It a good
starting point for further research, but it's NOT the final word on ANY
subject.

No wonder they kicked your ass out of college.

You don't need to be rude. The fact is that the best way to purchase pro
audio equipment is to read all the spec sheets, normalize all the data, and
then pick the best one. To do anything else is a profound waste of time -
you only need to actually listen to the equipment to verify it has no faults
in operation.

I wrote my entire thesis from data gleaned by reading Wikipedia. Granted
that wasn't the only source, but it sure saved a lot of time.

Bob

soundhaspriority wrote:

Also, they're
electrets, not AT back electrets, but real electrets, with the greater noise
that implies.

About this you are incorrect. Electrets have _no_ inherent disadvantage
over externally biased capsules. In many regards, noise among them, they
have the advantage.


Bob
--

"Things should be described as simply as possible, but no simpler."

A. Einstein

soundhaspriority wrote:
"Mike Rivers" wrote in message
oups.com...
soundhaspriority wrote:

You may want to consider getting some Avenson Audio STO-2s.
They look
like an inexpensive alternative to Earthworks. But these mics have about
10
dB more self noise than typical.
The orignal Earthworks measurement style mics are a little on the noisy
side. They made better (quieter) models later. It comes with the
territory when you have a small diaphragm - not a lot of output for a
given SPL, so for the same voltage out of the microphone you get more
noise.

Also, they're
electrets, not AT back electrets, but real electrets, with the greater
noise
that implies.
An electret is the electrostatic equivalent of a permanent magnet.
They're all real, and they're all "back." Back when manufacturers first
started to make inexpensive mics, they used electrets to save the cost
of providing a DC polarizing voltage, and at the time, all of the
electret mic capsules were cheap and crummy. There's no reason why an
electret mic capsule can't be good, it's just that the only market for
electrets at the time were in cheap mics. The Shure SM-81, which has
been around for over 25 years, has an electret capsule and it sounds
fine and is reasonably quiet for mics of that period. New ones are even
quieter.

Don't perpetuate rumors about the technology based on when product
demand was for cheap electrets.

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the best
ones can now rival capacitor mics in every respect apart from low noise..."
The article says that electrets can be made that are the equal... but also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

You should edit that entry and correct it. External polarization can be a
noise source that electrets are free of and electrets have no extra
mechanism for creating noise.


Noise in a condenser microphone is due to three factors:
1. Brownian motion (size of diaphram)
2. Noise figure of the FET amplifier

Good to here.

3. Strength of the polarization field.

Doesn't affect SNR. Affects sensitivity. Sensitivity is a kind of gain
and that due to polarization is applied identically to both the signal and
to the self noise.

A third noise source that is seldom reported but that can be larger than
either of the others is the noise of the pressure equalization port in an
omni or the acoustic front to back resistance in a gradient mic. An
acoustic resistance is as much a source of noise as is the electrical
equivalent.

The obvious candidate for the difference in noise between the best available
electrets versus the best available condenser microphones would be with
respect to factor 3.

If it were correct.

Therefore, this is not a rumor; it is a fact that in choice of an electret,
one gives up some noise.

Wiki is very subject to inclusion of rumor. :-)


Bob
--

"Things should be described as simply as possible, but no simpler."

A. Einstein

soundhaspriority wrote:

One other thing that peeves me about electrets is the sensitivity to high
temperature. A-T warns not to expose to temperatures over 110F. This is all
too easily reached by accident during travel. While many people have boasted
that their good German mikes are still good after many years, the electret
inevitably depolarizes sooner or later.

A-T says that about depolarization? New materials, e.g. PVDF and teflon,
have enormous bulk resistance to charge leakage. The difference in the
bulk resistance between room temperature and the highest reasonable ambient
is not enough to make a difference in your lifetime (or probably that of
yours and your grandchildren.)


Bob
--

"Things should be described as simply as possible, but no simpler."

A. Einstein

On Thu, 04 May 2006 02:13:42 -0700, Bob Cain
wrote:



I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the best
ones can now rival capacitor mics in every respect apart from low noise..."
The article says that electrets can be made that are the equal... but also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

You should edit that entry and correct it. External polarization can be a
noise source that electrets are free of and electrets have no extra
mechanism for creating noise.


Noise in a condenser microphone is due to three factors:
1. Brownian motion (size of diaphram)
2. Noise figure of the FET amplifier

Good to here.

3. Strength of the polarization field.

Doesn't affect SNR. Affects sensitivity. Sensitivity is a kind of gain
and that due to polarization is applied identically to both the signal and
to the self noise.

It wouldn't affect SNR if Brownian motion were the dominant source.
The noise of a microphone is, however determined almost 100%
electrically in the amplifier, so anything you can do it increase the
signal level - like increasing the bias voltage will, up to the point
where it no longer dominates - improve the SNR.

A third noise source that is seldom reported but that can be larger than
either of the others is the noise of the pressure equalization port in an
omni or the acoustic front to back resistance in a gradient mic. An
acoustic resistance is as much a source of noise as is the electrical
equivalent.

Certainly, but the resistance of the port is in parallel with the lack
of resistance of the open front, so its effect is small.

The obvious candidate for the difference in noise between the best available
electrets versus the best available condenser microphones would be with
respect to factor 3.

If it were correct.

Most non-electret condensor mics are limited by the 48V bias supply
anyway - so no big deal.

Therefore, this is not a rumor; it is a fact that in choice of an electret,
one gives up some noise.

Wiki is very subject to inclusion of rumor. :-)

Indeed. If you want low noise, you forget bias entirely and use an RF
condensor like a Sennheiser MKH series.

d

--
Pearce Consulting
http://www.pearce.uk.com

soundhaspriority wrote:

This implies that the technology used to create a strong field by the use of
electrets is not universally shared among all the maunfacturers of
electrets.

Don't believe it. All electrets are plasma poled. Make it nearly molten
with a high temp neutral plasma, apply a bias field that separates charge,
embedding one into the material and cool it in the presence of the field.
I'm pretty sure it's the electrons and not the ions that are embedded.


Bob
--

"Things should be described as simply as possible, but no simpler."

A. Einstein

Don Pearce wrote:

3. Strength of the polarization field.

Doesn't affect SNR. Affects sensitivity. Sensitivity is a kind of gain
and that due to polarization is applied identically to both the signal and
to the self noise.

It wouldn't affect SNR if Brownian motion were the dominant source.
The noise of a microphone is, however determined almost 100%
electrically in the amplifier, so anything you can do it increase the
signal level - like increasing the bias voltage will, up to the point
where it no longer dominates - improve the SNR.

Well put Don !

If you want low noise, you forget bias entirely and use an RF
condensor like a Sennheiser MKH series.

Isn't noise then determined at least in part by the purity of the RF oscillator ?

Graham

On Thu, 04 May 2006 10:52:00 +0100, Pooh Bear
wrote:



Don Pearce wrote:

3. Strength of the polarization field.

Doesn't affect SNR. Affects sensitivity. Sensitivity is a kind of gain
and that due to polarization is applied identically to both the signal and
to the self noise.

It wouldn't affect SNR if Brownian motion were the dominant source.
The noise of a microphone is, however determined almost 100%
electrically in the amplifier, so anything you can do it increase the
signal level - like increasing the bias voltage will, up to the point
where it no longer dominates - improve the SNR.

Well put Don !

If you want low noise, you forget bias entirely and use an RF
condensor like a Sennheiser MKH series.

Isn't noise then determined at least in part by the purity of the RF oscillator ?

Graham

Yes, but making quiet oscillators is no problem

d

--
Pearce Consulting
http://www.pearce.uk.com

"soundhaspriority"
wrote in message
"Mike Rivers" wrote in message
oups.com...

soundhaspriority wrote:

You may want to consider getting some Avenson Audio
STO-2s.

They look
like an inexpensive alternative to Earthworks. But
these mics have about 10
dB more self noise than typical.

The orignal Earthworks measurement style mics are a
little on the noisy side. They made better (quieter)
models later. It comes with the territory when you have
a small diaphragm - not a lot of output for a given SPL,
so for the same voltage out of the microphone you get
more noise.
Also, they're
electrets, not AT back electrets, but real electrets,
with the greater noise
that implies.

An electret is the electrostatic equivalent of a
permanent magnet. They're all real, and they're all
"back." Back when manufacturers first started to make
inexpensive mics, they used electrets to save the cost
of providing a DC polarizing voltage, and at the time,
all of the electret mic capsules were cheap and crummy.
There's no reason why an electret mic capsule can't be
good, it's just that the only market for electrets at
the time were in cheap mics. The Shure SM-81, which has
been around for over 25 years, has an electret capsule
and it sounds fine and is reasonably quiet for mics of
that period. New ones are even quieter. Don't perpetuate rumors about
the technology based on
when product demand was for cheap electrets.

I stand corrected on the issue of the backplate. However,
your assertion that equally good microphones are made by
either method is not supported by this Wikipedia article:
http://en.wikipedia.org/wiki/Microphone I quote: Though
electret mics were once considered low-cost and low
quality, the best ones can now rival capacitor mics in
every respect apart from low noise..." The article says
that electrets can be made that are the equal... but
also, ARE NOT made that are the equal in terms of noise.
The article does not explain why quiet electrets cannot
be made, but it quite unequivocally states that they are
not.
Noise in a condenser microphone is due to three factors:
1. Brownian motion (size of diaphram)
2. Noise figure of the FET amplifier
3. Strength of the polarization field.

The obvious candidate for the difference in noise between
the best available electrets versus the best available
condenser microphones would be with respect to factor 3.

Therefore, this is not a rumor; it is a fact that in
choice of an electret, one gives up some noise.

Where is it written in stone that electrets have a weak polarization field?

Hint: it isn't.

soundhaspriority wrote:

One other thing that peeves me about electrets is the sensitivity to high
temperature. A-T warns not to expose to temperatures over 110F. This is all
too easily reached by accident during travel.

Well, it's probalby not a good idea to expose your externally polarized
mics to high temperatures either. One thing that might (permanently)
affect electrets more than conventionally polarized mics is high
humidity. When I was in a TV studio in Japan about 35 years ago, they
had a number of Sony electret mics that they stored in dessicator jars.
I expect that electret materials have improved since then - at the time
I think it was a wax and now they use plastic materials.

While many people have boasted
that their good German mikes are still good after many years, the electret
inevitably depolarizes sooner or later.

I have a couple of Sony ECM-21s (my first condenser mics) that I've had
since 1969 and they still work. By today's standards, they're pretty
crummy mics and I really don't have any use for them, but they're still
mics after all those years. If you purchase an electret mics today
because you like its sound, and if you don't abuse it and aren't
careless about storage, it'll still be good by the time you get tired
of it. And, yes, people even get tired of their U87s. g

"Mike Rivers" wrote...
I have a couple of Sony ECM-21s (my first condenser mics) that I've
had
since 1969 and they still work. By today's standards, they're pretty
crummy mics and I really don't have any use for them, but they're
still
mics after all those years.

OTOH, my ECM-22's of approx. the same vintage are deaf as a post.

soundhaspriority wrote:

One other thing that peeves me about electrets is the sensitivity to high
temperature. A-T warns not to expose to temperatures over 110F. This is all
too easily reached by accident during travel. While many people have boasted
that their good German mikes are still good after many years, the electret
inevitably depolarizes sooner or later.

Loss rate on the SM-81s in Shure storage has been around 0.5 dB every
thirty years. You can live with that.

Most of the mikes that had high leakage rates (and the early Sony ECM
series mikes are notorious) had cheap electret materials that were known
to be leaky but were used anyway to reduce cost.
--scott

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

Pooh Bear wrote:
Don Pearce wrote:

If you want low noise, you forget bias entirely and use an RF
condensor like a Sennheiser MKH series.

Isn't noise then determined at least in part by the purity of the RF oscillator ?

Yes, but you can do really well. You can get to the point where, even with
a fairly large capsule, the Brownian movement is by far the dominant noise
source.

Your real issue then becomes the linearity of the discriminator.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

soundhaspriority wrote:

I stand corrected on the issue of the backplate. However, your assertion
that equally good microphones are made by either method is not supported by
this Wikipedia article: http://en.wikipedia.org/wiki/Microphone I quote:
Though electret mics were once considered low-cost and low quality, the best
ones can now rival capacitor mics in every respect apart from low noise..."
The article says that electrets can be made that are the equal... but also,
ARE NOT made that are the equal in terms of noise. The article does not
explain why quiet electrets cannot be made, but it quite unequivocally
states that they are not.

Wikipeida is one thing, and B&K and DPA mics are another. Seek a
top-shelf electret and ye shall find.

--
ha

soundhaspriority wrote:

I've read this board long enough, so now I know everything. I can read a
datasheet, and that's the only way to buy equipment - specs.

The way to purchase pro gear is to use it and determine how it performs
on the road. Everything performs very well on the showroom floor. Lack
of real standardization in spec presentation leaves one without really
detailed clues to sound.

--
ha

Robert Morein wrote:
On 5/4/06 13:20, in article ,
"Agent 86" wrote:

Do you understand that ANYBODY can write ANYTHING in Wiki? It a good
starting point for further research, but it's NOT the final word on ANY
subject.

No wonder they kicked your ass out of college.

You don't need to be rude. The fact is that the best way to purchase pro
audio equipment is to read all the spec sheets, normalize all the data, and
then pick the best one. To do anything else is a profound waste of time -
you only need to actually listen to the equipment to verify it has no faults
in operation.

I wrote my entire thesis from data gleaned by reading Wikipedia. Granted
that wasn't the only source, but it sure saved a lot of time.


Buncha****ski. Wikipedia is merely a public collection of widely known
stuff. Anyone with an ax to grind or to sell can and does write for
Wiki.

Pro audio spec sheets are useless to inform you which product actually
will hold up over time, which product you will be able to get parts or
service for, which product you can get a good deal on, which product
your clients will respect you for using, and a host of other questions
which need answering.

You can make very good vocal recordings using many fine economical
mics. If you are selling studio time in a competitive market you had
better have certain pieces in your mic locker.

Und so weiter.

A good friend of mine did a church job where there was going to be a
house system and a extensive Allen Organ speaker system replaced with
one system. He specified some custom cabs and used some high dollar
drivers and amps. The bottom line was a system using nothing but Peavey
could have done the job, but he knew this church had already decided to
spend a certain sum, and he spent just a tad over. He got the job. Had
he bid a good economy system he would have been sent home empty-handed.

"Bob Cain" wrote in message
...
soundhaspriority wrote:

One other thing that peeves me about electrets is the sensitivity to high
temperature. A-T warns not to expose to temperatures over 110F. This is
all
too easily reached by accident during travel. While many people have
boasted
that their good German mikes are still good after many years, the
electret
inevitably depolarizes sooner or later.

A-T says that about depolarization? New materials, e.g. PVDF and teflon,
have enormous bulk resistance to charge leakage.

The difference in the
bulk resistance between room temperature and the highest reasonable
ambient
is not enough to make a difference in your lifetime (or probably that of
yours and your grandchildren.)

I haven't studied depolarization in detail. However, it seems to me that the
P vector can weaken due to multiple mechanisms. One would be
electromigration over the surface, or through the material. That would be
influenced by the bulk conductivity. OTOH, the actual polarization mechanism
occurs in a time frame where conductivity can be said to be absent; it
results from the alignment of polar molecules. Analogously, magnets decay,
even though there is no magnetic current.

"Richard Crowley" wrote in message
...
"Mike Rivers" wrote...
I have a couple of Sony ECM-21s (my first condenser mics) that I've had
since 1969 and they still work. By today's standards, they're pretty
crummy mics and I really don't have any use for them, but they're still
mics after all those years.

OTOH, my ECM-22's of approx. the same vintage are deaf as a post.
One accidental episode, exposed to the sun in a hatchback, could do it, at
least with the older materials.