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

From: Fernando Lopez-Lezcano <nando@email-addr-hidden>
Date: Fri May 12 2006 - 23:28:23 EEST

On Sat, 2006-05-13 at 06:00 +1000, D. Sen wrote:
> Look at the specs. The output is definitely line-level. The function of
> a pre-amp is to produce line-level output and this does it.

Not really. Please compare to the specs of a real mic preamp, please,
for example:
  http://www.rme-audio.com/english/micpreamps/quadmic.htm
(which would be an appropriate companion to the multiface)

In particular: "Amplification can be set between 10 and 60 dB". 60dB of
gain expressed as a voltage ratio would be amplifying the signal by
1000. I would imagine you would need to use 40 to 60dB to amplify a mic
to line level so you are at least a factor of 10 below what would be
needed.

> It is sold by B&K and they swear by it.

(they can swear all they want but that's not gonna make it amplify the
signal more :-)

The key here (as outlined before in the thread) is gain. This signal
conditioner's gain is too low (probably by a factor of at least 10) to
act as a mic preamp _unless_ your line input has additional gain you can
dial in (which is probably why you can use it with other equipment).

-- Fernando

> Paul Winkler wrote:
> > On Sat, May 13, 2006 at 04:16:28AM +1000, D. Sen wrote:
> >> This is what is being used between the microphone and the multiface:
> >>
> >> http://www.bksv.com/pdf/4416B.pdf
> >>
> >> This is providing line-level output to the multiface.
> >
> > What you have there isn't really a microphone preamp. Max gain of 10
> > isn't very much at all, it's what, 20 dB?
> >
> > Commercial mic preamps typically have at least 60 dB of gain available.
> >
Received on Sat May 13 00:15:07 2006

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