Re: [linux-audio-user] Recording Level using Audacity and a Multiface card

From: D. Sen <dsen@email-addr-hidden>
Date: Tue May 16 2006 - 22:36:59 EEST

Actually, after Sampo's hint, everything does indeed work fine (without
the 10x gain of the power-supply/conditioner, I might add).

Cheers,
DS
Asbjørn Sæbø wrote:
> On Sat, May 13, 2006 at 08:03:48AM +1000, D. Sen wrote:
>> Yes, sure.
>>
>> Here are the relevant links for the 4189 + 2671 microphone housing in
>> our setup, that connects to the Deltatron power supply.
>>
>> http://www.bksv.com/pdf/Bp1380.pdf
>
> That is a microphone, indeed. A B&K measurement microphone, that is.
> (A note to those not familiar with B&K measurement equipment: These are
> not quite like "normal" microphones. But they are of very high
> quality.)
>
> According to your linke, this microphone has a sensitivity of 50mV/Pa.
>
>
>> http://www.bksv.com/pdf/bp2111.pdf
>
> And this is the preamplifier. (Which would, in audio, normally be
> considered part of the microphone.)
>
> This one has, according to the link, a peak output of 7 volts,
> corresponding to an SPL of 138dB for a 50mV/Pa microphone. Your 94dB
> signal is 44 dB below that. Which means that the output level after the
> preamplifier will be
>
> l = 7 * 10^(-44/20) = 0.044
>
> And 0.044 volts is quite a bit below full scale line-level. However,
> adding the 10x gain of your amplifier you should be at 0.44 v, which is
> certainly in the ballpark of consumer line-level.
>
>
> After looking closer at it, your setup actually seems to make some
> sense. Your amplifier (the 4416) is not one normally used for
> amplifying microphone signals, but rather accelerometers and the like.
> (As your links says: "conditioner for use with ISOTRON(R) or other
> piezoelectric voltage mode transducuers.")
> But the preamplifier (the 2111) _seems_ to be of a special kind intended
> just for interfacing microphones to this kind of amplifier, so you are
> probably right in that it should work.
>
>
> Asbjørn
>
>
Received on Wed May 17 04:15:11 2006

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