[Phil Allison]

"Iain Cherchus"

** Your first stage fixed gain of over 300 times is way too high.

Input overload will be a constant problem - particularly with a
condenser mic.

An input pad will make things noisy again.

Much depends on the recording.


** It all depends on Ian's proposed pre- amp here

- you ****ing tenth wit !!!



........ Phil

[Phil Allison]

"Patrick Turneroid"

** 68 dB is absolutely NOT an acceptable s/n ratio for a professional
mic
preamp operating in the middle of it's gain range. The figure needs to be
circa 90 dB - as is routinely obtained with standard commercial
designs.

Plus you have omitted the self noise of the mic - which will degrade
that
figure another 3dB to a horrible 65dB. Plus you omitted the output stage
noise, which will reduce the ratio further by couple of dB at that gain
setting.

A joke.

Something has to give.

If the attempt at recording is serious, and a 90bB SNR is wanted,
then he could throw away 20dB of amp gain but increase the mic signal by
20 dB.


** My point exactly.

Then design the mic pre-amp like any other, with 60 dB of gain max and a
variable gain stage after the input tranny to preserve overload margin.



I have never examined a studio mic's impedance or output voltage
characteristics or noise production.


** Better butt out of THIS discussion then.


Iain should know, or even Arny, both claim experience, and you might
know,
but are too lazy to tell us all we might need to know, or where
we may find a reliable source of the info.


** You could try coming down of that high horse you keep riding till it
drops - and ask.

I won't hold my breath.



I have found that many cds and vinyls have noise well above the amp I
use.
probably these recordings have a worse SNR than 65 dB.


** Got SFA to do with the noise performance of individual mics and their
pre-amps.

The background noise you may hear on a recording as sold to the public is
mainly due to multiple generations of tape used, overuse of signal
processing and poor quality vinyl, if that is involved.

Not mics or mic pre-amps..


....... Phil

[Phil Allison]

"Iain Cherchus"

Yes that's common. I have many CDs on which one can clearly
hear the noise floor, followed by a digital "fade to black"


** So have I.

The noise I hear on the CD is from a tape recorder, playing a copy of a copy
of a copy of a copy some original tape that was about 18 dB quieter than the
final generation copy. Every time an (analogue) tape is copied, the s/n
worsens by 3 to 6dB.

One of the nicest things about digital audio is that this does not happen,
no matter how many generation are involved.




....... Phil

[Patrick Turner]

Phil Allison wrote:

"Iain Cherchus"

Yes that's common. I have many CDs on which one can clearly
hear the noise floor, followed by a digital "fade to black"

** So have I.

The noise I hear on the CD is from a tape recorder, playing a copy of a copy
of a copy of a copy some original tape that was about 18 dB quieter than the
final generation copy. Every time an (analogue) tape is copied, the s/n
worsens by 3 to 6dB.

One of the nicest things about digital audio is that this does not happen,
no matter how many generation are involved.

...... Phil

And people keep telling me they are about to put all their precious
vinyl onto
CD.

And then they use the most appalling TT and pramp they can find....

But one guy I know has all his vinyl CD'd by a pro with very good gear.
And the recordings are often very old, SNR maybe 55dB....

Two glasses of wine improves the sound.

Patrick Turner.

[Iain Churches]

"Phil Allison" wrote in message
...


** Your first stage fixed gain of over 300 times is way too high.

Input overload will be a constant problem - particularly with a
condenser mic.

An input pad will make things noisy again.

Much depends on the recording.


** It all depends on Ian's proposed pre- amp here

- you ****ing tenth wit !!!

Much depends on the genre of the recording. If Ian is
working with a rock/pop/jazz group, then the signal levels
will more than mask the noise floor of the recording chain.

If he is recording a strings quartet in a large hall, then he
may well run into trouble.

[Iain Churches]

"Phil Allison" wrote in message
...

"Iain "

Yes that's common. I have many CDs on which one can clearly
hear the noise floor, followed by a digital "fade to black"


** So have I.

The recordings to which I refer are DDD.

The noise I hear on the CD is from a tape recorder, playing a copy of a
copy of a copy of a copy some original tape that was about 18 dB quieter
than the final generation copy. Every time an (analogue) tape is copied,
the s/n worsens by 3 to 6dB.

Discs made from third generation analogue masters? You have some pretty
crappy recordings in your collection, Phil. Even in a licensing deal the
contract usually includes a clause to make the original master available
to the licensee for production.

Most analogue masters, with the exception of classical music, were
mixed from multitrack, so what possible reason is there to copy a
quarter inch master? If something needs to be changed, then a
remix is easily done.

In addition, cutting consoles, and CD mastering facilities have
a greater variety of outboard equipment, limiters, compressors,
expanders, equalisers, phase correction etc etc than found in a
tape copy facility, so using a corrected analogue copy for
production is neither necessary nor prudent.
Most masters include a prod'n card on which is
marked the details of any processing that was done.


Iain

[Phil Allison]

"Iain Cherchus"
Turneroid Fool

probably these recordings have a worse SNR than 65 dB.

Yes that's common. I have many CDs on which one can clearly
hear the noise floor, followed by a digital "fade to black"


** So have I.

The recordings to which I refer are DDD.


** With mic pre-amp noise 65 dB down ??

How the **** would YOU know that ??

Proves SFA even if you DO really have such atrocious CDs.


Discs made from third generation analogue masters?


** Very common to find 4 or 5 tape generations between the original
multitrack and a CD release 30 years later.

Very common in Australia to have an LP pressed from 4th or 5th generation
tape of material that originated in Europe or the USA.

Don't you know anything about the record business in the vinyl era ?



........ Phil

[Ian Bell]

Patrick Turner wrote:



Phil Allison wrote:

"Patrick Turner"

** For serious recording work, mic gain of 1000 times is not usable
as
it
results in excessive background noise - consisting audible hiss from
the mic
and pre -amp PLUS amplified noise from the environment.

Having 1000 times gain at only half knob setting is UTTERLY INSANE
!!

The OP has not built his fantasy tube pre-amp yet - when an if he
does,
he will soon see it is not a game for mugs like him.


The noise of the amp is determined by its input noise of perhaps 2uV,
some 68dB below the 5mV signal from the mic tranny.

** 68 dB is absolutely NOT an acceptable s/n ratio for a professional
mic preamp operating in the middle of it's gain range. The figure needs
to be
circa 90 dB - as is routinely obtained with standard commercial
designs.

Plus you have omitted the self noise of the mic - which will degrade
that figure another 3dB to a horrible 65dB. Plus you omitted the output
stage noise, which will reduce the ratio further by couple of dB at that
gain setting.

A joke.

Something has to give.

If the attempt at recording is serious, and a 90bB SNR is wanted,
then he could throw away 20dB of amp gain but increase the mic signal by
20 dB.


I practice, a 90dB SNR is often not achievable. Resistive noise of a 150 ohm
source in a 20KHz bandwidth is about -131dBm. For a 90 dB SNR, even a 1dB
NF preamp could have no more than 40dB gain which would be inadequate for
many applications.


Ian

[Phil Allison]

"Iain Churches"


** It all depends on Ian's proposed pre- amp here

- you ****ing tenth wit !!!

Much depends on the genre of the recording.

** It all depends on Ian's proposed pre- amp here

- you ****ing tenth wit !!!



....... Phil

[Iain Churches]

"Ian Bell" wrote in message
...
Iain Churches wrote:


"Ian Bell" wrote in message
...
Ian Iveson wrote:

Ian Bell said:

This is where the cancellation appears to take place in the CF.

Then there is something very badly wrong with your CF or your
simulation.


Personally I strongly suspect the simulation.

Why don't you post your circuit diagram, perhaps to ABSE? Easy done.
Maybe you could show pictures of your graphs too. That would be
instructive.

cheers, Ian

I assume ABSE is a binaries news group? if so my ISP does not provide
access
to binary groups.

Ian. I can host them for you if required.

Iain

That is a very kind offer but I think I'll do what I did last time Patrick
asked to see a schematic - post them to one of my own web sites - now if I
can just remember how I did it last time ;-)

OK. Please post the link.
Iain

[Iain Churches]

"Phil Allison" wrote in message
...

probably these recordings have a worse SNR than 65 dB.

Yes that's common. I have many CDs on which one can clearly
hear the noise floor, followed by a digital "fade to black"


** So have I.

The recordings to which I refer are DDD.


** With mic pre-amp noise 65 dB down ??

I simply stated, in agreement to what Patrick wrote,
that many CDs have a noise floor clearly audible
above that of the replay chain, which in my listening
room incorporates a tube pre and power amp.

How the **** would YOU know that ??

Proves SFA even if you DO really have such atrocious CDs.

Now you are confused Phil. Sit down, and count to 100.
Shall I compile a list for you? Would you bother to listen
to these recordings if I did? Probably not.



Discs made from third generation analogue masters?


** Very common to find 4 or 5 tape generations between the original
multitrack and a CD release 30 years later.

Please substantiate this wild claim.

Very common in Australia to have an LP pressed from 4th or 5th generation
tape of material that originated in Europe or the USA.

Commiserations. The two major companies that I worked for used to
ship metalwork (pressing matrices grown from acetates cut from the original
tape masters) so Australia should not have been any worse off than the
rest of the world in this respect. This was a guarantee of mastering
quality although the quality of the actual pressings was down to local
skill.

One would have thought that this problem would have been resolved
with the advent of digital, but there are still considerable differences,
particularly in pop music, between CDs mastered in different locations.

Don't you know anything about the record business in the vinyl era ?

Yes indeed. I started at Decca in 1965. I spent two years in disc
cutting as a part of my training. There are large numbers of discs
with my cutting ID. -xC (where x was the cut number)

Tell us, please, of your own experience in the record business.

Iain

[Ian Bell]

Iain Churches wrote:


"Ian Bell" wrote in message
...
Ian Iveson wrote:

Ian Bell said:

This is where the cancellation appears to take place in the CF.

Then there is something very badly wrong with your CF or your
simulation.


Personally I strongly suspect the simulation.

Why don't you post your circuit diagram, perhaps to ABSE? Easy done.
Maybe you could show pictures of your graphs too. That would be
instructive.

cheers, Ian

I assume ABSE is a binaries news group? if so my ISP does not provide
access
to binary groups.

Ian. I can host them for you if required.

Iain

That is a very kind offer but I think I'll do what I did last time Patrick
asked to see a schematic - post them to one of my own web sites - now if I
can just remember how I did it last time ;-)

Ian

[Ian Bell]

Iain Churches wrote:


"Ian Bell" wrote in message
...
Phil Allison wrote:


"Ian Bell"

** Then why the hell have *2* triode gain stages with well over 1000
times gain ??

Makes your total gain OVER 10,000 TIMES !!

Madness.


Stage gain is about 30dB and transformer gain is 20dB - max gain
20+30+30=80dB - excessive even for a mic pre. Trouble is, for a nominal
+4dBm output, a single 30dB stage and transformer will give an input
sensitivity of just -46dBm which is barely adequate in many situations.


** Your first stage fixed gain of over 300 times is way too high.

Input overload will be a constant problem - particularly with a
condenser mic.

An input pad will make things noisy again.


....... Phil

Indeed. That's why I plan to use an input transformer designed for use in
a
Helios console. It has a tap on the secondary that gives a 1:1 ratio
instead of 1:10. A switch to select between the two acts like a 20dB pad.

Dick S knew a trick or two:-)
One saw this on the Schlumberger desks, and also those built under
licence for Scandinavian broadcast companies by Kajaani Electronics.


That he did, and reputedly a really nice guy too. His EQ was liked a lot by
musicians and engineers alike.

Ian
Iain

[Iain Churches]

"Ian Bell" wrote in message
...
Iain Churches wrote:


"Ian Bell" wrote in message
...
Phil Allison wrote:


"Ian Bell"

** Then why the hell have *2* triode gain stages with well over 1000
times gain ??

Makes your total gain OVER 10,000 TIMES !!

Madness.


Stage gain is about 30dB and transformer gain is 20dB - max gain
20+30+30=80dB - excessive even for a mic pre. Trouble is, for a
nominal
+4dBm output, a single 30dB stage and transformer will give an input
sensitivity of just -46dBm which is barely adequate in many
situations.


** Your first stage fixed gain of over 300 times is way too high.

Input overload will be a constant problem - particularly with a
condenser mic.

An input pad will make things noisy again.


....... Phil

Indeed. That's why I plan to use an input transformer designed for use
in
a
Helios console. It has a tap on the secondary that gives a 1:1 ratio
instead of 1:10. A switch to select between the two acts like a 20dB
pad.

Dick S knew a trick or two:-)
One saw this on the Schlumberger desks, and also those built under
licence for Scandinavian broadcast companies by Kajaani Electronics.


That he did, and reputedly a really nice guy too. His EQ was liked a lot
by
musicians and engineers alike.

A long time ago I worked at a company that had three studios, one of which
had a Helios console. It was so popular that it was fitted with wheels so
that
it could be careful moved between two adjacent control rooms.

Iain

[Ian Bell]

Eeyore wrote:



Ian Bell wrote:

I plan to use an input transformer designed for use in a
Helios console.

You have one lying around ?


No, I have TWO lying around - I am also building a replica Helios mic
pre/EQ.

It has a tap on the secondary that gives a 1:1 ratio
instead of 1:10. A switch to select between the two acts like a 20dB pad.

Oh dear.

Helios didn't make valve consoles.


No but Dick's transistor preamps have a remarkably hi-z input impedance
(sevral hundred K).

May I suggest a Lundahl transformer ? If you have to have a transformer,
you might as well use a good one.


The Helios ones I have are made by Sowter (type 7490)- also good ones ;-)


Ian

[Phil Allison]

"Iain Cherchus"

probably these recordings have a worse SNR than 65 dB.

Yes that's common. I have many CDs on which one can clearly
hear the noise floor, followed by a digital "fade to black"


** So have I.

The recordings to which I refer are DDD.


** With mic pre-amp noise 65 dB down ??

I simply stated, in agreement to what Patrick wrote,
that many CDs have a noise floor clearly audible
above that of the replay chain,


** So it is nothing like -65 dB and so does not support the Turneroids
words.

You ****ING PITA MORON.



** Very common to find 4 or 5 tape generations between the original
multitrack and a CD release 30 years later.

Please substantiate this wild claim.


** Don't you know anything about the record business in the vinyl era ?

Obviously not.


Very common in Australia to have an LP pressed from 4th or 5th generation
tape of material that originated in Europe or the USA.

Commiserations.


** Get ****ed.


Don't you know anything about the record business in the vinyl era ?

Yes indeed. I started at Decca in 1965.


** Shame you had your head stuck permanently up you arse and learned NOTHING
..

Proves you were just another ASD ****ed operative, bum boy and tea maker.



........ Phil

[Phil Allison]

"Ian the Bell Boy "

I practice, a 90dB SNR is often not achievable.


** With sufficient SPL level at the mic - it is always achievable.


Resistive noise of a 150 ohm
source in a 20KHz bandwidth is about -131dBm. For a 90 dB SNR, even a 1dB
NF preamp could have no more than 40dB gain ....


** Absolute GARBAGE.

One sets the gain to suit the signal level.

A 150 ohm ( dynamic) mic outputting 30 mV ( -28 dbm) has a possible s/n
ratio of 103 dB.

With 40 dB of gain, the level coming out of first stage of a mic pre-amp is
then 3 volts rms.

No problem for any SS or tube cct.

Then you can attenuate the level to 0dbm, if you like, with no change in
s/n.


The is no FOOL bigger than one who falsely imagines he already knows what he
does not.

The Bell Boy is a classic ding -a -ling.




....... Phil

[Phil Allison]

"Ian the Bell Boy Scumbag "


That he did, and reputedly a really nice guy too. His EQ was liked a lot
by
musicians and engineers alike.



** LOL !!

Shame about his damn IQ, then.



........ Phil

[Ian Bell]

Phil Allison wrote:


"Ian the Bell Boy "

I practice, a 90dB SNR is often not achievable.


** With sufficient SPL level at the mic - it is always achievable.


Resistive noise of a 150 ohm
source in a 20KHz bandwidth is about -131dBm. For a 90 dB SNR, even a 1dB
NF preamp could have no more than 40dB gain ....


** Absolute GARBAGE.

One sets the gain to suit the signal level.

Of course you do, and the lower the signal level the worse the SNR. But I
guess the blindingly obvious eludes you.


A 150 ohm ( dynamic) mic outputting 30 mV ( -28 dbm) has a possible s/n
ratio of 103 dB.


Of course it does you idiot simply because it is 103dB above its own noise
floor.

By the same token the same mic with an output of -40dBm cannot achieve
better than a 91dB SNR.

And the same mic with an output of -60dBm cannot achieve a SNR better than
70dB SNR.

With 40 dB of gain, the level coming out of first stage of a mic pre-amp
is then 3 volts rms.

No problem for any SS or tube cct.

Then you can attenuate the level to 0dbm, if you like, with no change in
s/n.


The is no FOOL bigger than one who falsely imagines he already knows what
he does not.


Words you had best heed.

Ian

[Eeyore]

Ian Bell wrote:

I practice, a 90dB SNR is often not achievable. Resistive noise of a 150 ohm
source in a 20KHz bandwidth is about -131dBm.

No it isn't.

You mean -131 dBu.

Graham

[Phil Allison]

"Eeysore"

I practice, a 90dB SNR is often not achievable. Resistive noise of a 150
ohm
source in a 20KHz bandwidth is about -131dBm.

No it isn't.

You mean -131 dBu.


** The Bell Boy ****wit is from the audio "dark ages " when " dBm " did
commonly mean the same as " dBu" does now.

The previous context made it quite clear that voltages rel 0.775 volts rms
is the topic at hand.

God knows what the Eeysore pedant has in his.



........ Phil

[Ian Bell]

Eeyore wrote:



Ian Bell wrote:

I practice, a 90dB SNR is often not achievable. Resistive noise of a 150
ohm source in a 20KHz bandwidth is about -131dBm.

No it isn't.

You mean -131 dBu.

Graham


Indeed I do. I had forgotten that the marketing guys like to quote relative
to a higher level just to make the figures look better.

Ian

[Ian Bell]

Phil Allison wrote:


** Which is NOTHING like your original ********:

" For a 90 dB SNR, even a 1dB NF preamp could have no more than 40dB gain
.... "

Which is PRECISELY what I said originally.

LOL

Ian

[Eeyore]

Ian Bell wrote:

Eeyore wrote:
Ian Bell wrote:

I practice, a 90dB SNR is often not achievable. Resistive noise of a 150
ohm source in a 20KHz bandwidth is about -131dBm.

No it isn't.

You mean -131 dBu.


Indeed I do. I had forgotten that the marketing guys like to quote relative
to a higher level just to make the figures look better.

What 'higher level' are you talking about ?

Graham

[Phil Allison]

"Eeysore Drongo: "

What 'higher level' are you talking about ?



** 1 dBu at 150 ohms = 4 mW.

Capice ?



...... Phil

[Ian Bell]

Eeyore wrote:



Ian Bell wrote:

Eeyore wrote:
Ian Bell wrote:

I practice, a 90dB SNR is often not achievable. Resistive noise of a
150 ohm source in a 20KHz bandwidth is about -131dBm.

No it isn't.

You mean -131 dBu.


Indeed I do. I had forgotten that the marketing guys like to quote
relative to a higher level just to make the figures look better.

What 'higher level' are you talking about ?

Graham



Sorry, brain on the blink again.

Ian

[robert casey]

But one guy I know has all his vinyl CD'd by a pro with very good gear.
And the recordings are often very old, SNR maybe 55dB....

Two glasses of wine improves the sound.


:-) And those CDs will have that vinyl sound to boot!

[Chris Hornbeck]

On Mon, 18 Jun 2007 08:29:11 +0100, Ian Bell
wrote:

I practice, a 90dB SNR is often not achievable. Resistive noise of a 150 ohm
source in a 20KHz bandwidth is about -131dBm. For a 90 dB SNR, even a 1dB
NF preamp could have no more than 40dB gain which would be inadequate for
many applications.

In practice, a 90dB SNR is *never* achievable, if recording
music in any conventional space. No room air handling, musicians,
or especially (if present) audience is quiet enough.

A *very* quiet room suitable for music recording, with nobody
breathing in it, might have a noise level, late at night without
the air conditioner running, of maybe 30dB SPL.


All good fortune,

Chris Hornbeck

[Eeyore]

Chris Hornbeck wrote:

On Mon, 18 Jun 2007 08:29:11 +0100, Ian Bell
wrote:

I practice, a 90dB SNR is often not achievable. Resistive noise of a 150 ohm
source in a 20KHz bandwidth is about -131dBm. For a 90 dB SNR, even a 1dB
NF preamp could have no more than 40dB gain which would be inadequate for
many applications.

In practice, a 90dB SNR is *never* achievable, if recording
music in any conventional space. No room air handling, musicians,
or especially (if present) audience is quiet enough.

A *very* quiet room suitable for music recording, with nobody
breathing in it, might have a noise level, late at night without
the air conditioner running, of maybe 30dB SPL.

Utter nonsence.

30dB SPL is quite loud. It's about the kind of background level I've measured
outdoor during the late evening in a small city (obviously not counting cars
driving past and chatty pedestrians in the immediate vicinity).

A decent studio should have no trouble reaching 15dB SPL or even better.

Air condition in studios is achieved with a low speed, large duct area method btw
to minimise noise.

In a recent test in British Grove studios, I found the loudest noise in the
equally quiet control room to be a wall wart for some rack gear. You need good
ears to hear that *AND* a VERY quiet room.

Graham

[Phil Allison]

"Chris Hornbeck"


In practice, a 90dB SNR is *never* achievable, if recording
music in any conventional space. No room air handling, musicians,
or especially (if present) audience is quiet enough.


** For a mic to produce a s/n ratio of 90 dB at its terminals only requires
the SPL at the diaphragm to be around 105 dB.

Very easily achieved by close micing a singing voice, drum kit, piano,
trumpet, clarinet etc etc. Close micing a drum kit can produce peak SPLs at
the mic of over 130dB !!

In any normal recording studio environment, if a mic's gain is advanced high
enough, electronically generated white noise ( hiss) becomes audible through
the monitors. Other ( distinctly different) noises maybe audible too, like
someone breathing 3 metres away or distant traffic noise leaking in.

On typical commercial recordings, this huge dB range is COMPRESSED down to a
much smaller range - rendering the background noise audible during quiet
passages, even on DDD CDs, when played at home at high volume settings or
when monitored on headphones.




........ Phil

[Chris Hornbeck]

On Tue, 19 Jun 2007 01:54:18 GMT, Eeyore
wrote:

A *very* quiet room suitable for music recording, with nobody
breathing in it, might have a noise level, late at night without
the air conditioner running, of maybe 30dB SPL.

Utter nonsence.

Go measure a real room and get back to me.

Chris Hornbeck

[Chris Hornbeck]

On Tue, 19 Jun 2007 12:29:57 +1000, "Phil Allison"
wrote:

In practice, a 90dB SNR is *never* achievable, if recording
music in any conventional space. No room air handling, musicians,
or especially (if present) audience is quiet enough.


** For a mic to produce a s/n ratio of 90 dB at its terminals only requires
the SPL at the diaphragm to be around 105 dB.

Very easily achieved by close micing a singing voice, drum kit, piano,
trumpet, clarinet etc etc. Close micing a drum kit can produce peak SPLs at
the mic of over 130dB !!

True, if that's what you consider to be "recording". I guess
that's the modern standard, but I don't agree with it.

Much thanks, as always,

Chris Hornbeck

[Phil Allison]

"Chris Hornbeck Uttere MORON "

True, if that's what you consider to be "recording". I guess
that's the modern standard, but I don't agree with it.


** **** off - IMBECILE





........ Phil

[Eeyore]

Chris Hornbeck wrote:

Eeyore wrote:

A *very* quiet room suitable for music recording, with nobody
breathing in it, might have a noise level, late at night without
the air conditioner running, of maybe 30dB SPL.

Utter nonsence.

Go measure a real room and get back to me.

I doubt many commercial SPL meters go low enought to measure the likes of
British Grove or Air.

The 30dB figure you snipped *was* a measurement though. And that was outside.
Next to a pub with a rock band playing too.

I reckon a quiet bedroom will make 15dB too. It is a fairly quite area here at
night it has to be said.

Graham

[Phil Allison]

"Eeysore"

The 30dB figure you snipped *was* a measurement though.


** But "A " weighted - of course.


I reckon a quiet bedroom will make 15dB too.


** Not if a live person has to read the meter on the mic - gentle
breathing noise is about 32 dBA at 1 metre !!


BTW:

You are all debating the WRONG issue.

Comparing raw dB SPL figures is a GROSS over simplification.

Natural background noise tends to be very much concentrated in the low to
mid frequency bands - while the noise from a dynamic mic and pre-amp is
*white noise* where the highest audio frequencies dominate.

It is very easy to hear the * white noise * contribution of a mic in a room
where the background noise tests 25 dB higher then that from the mic on a
unweighted SPL meter.

The human ear *easily* picks out the STEADY high pitched HISSSSSS from
other low frequency random and constantly VARYING ambient noises.

That is the REAL reason why studio mics and their pre-amps must be as quiet
as possible.

White noise sticks out like dog's balls.



....... Phil

[Chris Hornbeck]

On Tue, 19 Jun 2007 02:55:45 GMT, Eeyore
wrote:

A *very* quiet room suitable for music recording, with nobody
breathing in it, might have a noise level, late at night without
the air conditioner running, of maybe 30dB SPL.

Utter nonsence.

Go measure a real room and get back to me.

I doubt many commercial SPL meters go low enought to measure the likes of
British Grove or Air.

The 30dB figure you snipped *was* a measurement though. And that was outside.
Next to a pub with a rock band playing too.

I reckon a quiet bedroom will make 15dB too. It is a fairly quite area here at
night it has to be said.

I think it'd be fair to ask exactly how these numbers were
measured, because the measurement isn't trivial.

I *can* tell you that in America the real numbers are 15 to
20 dB higher. Never been to England; would very much love to;
but I find it difficult to believe it's that much quieter.

Here in noisy America it's an issue to build an isolation
box good enough to measure down to 15 dB SPL, not a trivial
deal-i-o.


My point, lost in the Gaffla, though, was that essentially
nobody recording music need worry about the noise of their
recording gear. Worry about arrangements; worry about intonation;
worry about singing; worry about mic location; worry about
how drunk the drummer is; worry about room acoustics; worry
about that big label contract; but don't worry about microphone
thermal noise. It's *not* what's holding you back.

Much thanks, as always,

Chris Hornbeck

[Eeyore]

Phil Allison wrote:

"Eeysore"

The 30dB figure you snipped *was* a measurement though.

** But "A " weighted - of course.

Yes.


I reckon a quiet bedroom will make 15dB too.

** Not if a live person has to read the meter on the mic - gentle
breathing noise is about 32 dBA at 1 metre !!

!!!!!

After a long run ?

Graham

[Phil Allison]

"Chris Hornbeck ****ing IDIOT "


My point, lost in the Gaffla, though, was that essentially
nobody recording music need worry about the noise of their
recording gear.


** What ASININE ****ING CRAP !!!!!!!!!!!


Worry about arrangements; worry about intonation;
worry about singing; worry about mic location; worry about
how drunk the drummer is; worry about room acoustics; worry
about that big label contract; but don't worry about microphone
thermal noise. It's *not* what's holding you back.


** With good quality, commercial mic pre-amps, that is true enough.

But with the pile of CRAP the Ian Bell Boy Moron is planning - it is
not.

You are a MONUMENTALLY AUTISTIC PITA FOOL - Hornbeck


**** the HELL OFF !!!!!!!!!!!!!



....... Phil

[Phil Allison]

"Eeysore ****wit "


I reckon a quiet bedroom will make 15dB too.

** Not if a live person has to read the meter on the mic - gentle
breathing noise is about 32 dBA at 1 metre !!

!!!!!

After a long run ?


** Go test it - you PITA pathetic pommy imbecile.




........ Phil

[Chris Hornbeck]

On Tue, 19 Jun 2007 03:31:42 GMT, Eeyore
wrote:

** But "A " weighted - of course.

Yes.

Any of us can design a weighting curve to manufacture
any number we like from any other number. In America
the number you've used is called "dbA" rather than "dB".

Thanks, as always,

Chris Hornbeck