[linux-audio-dev] scaling jackinput to dbSPL

Dominique Michel dominique.michel at citycable.ch
Tue Aug 15 16:22:48 UTC 2006

Le Tue, 15 Aug 2006 12:01:11 -0400,
Lee Revell <rlrevell at joe-job.com> a écrit :

> On Tue, 2006-08-15 at 16:51 +0100, Dan Mills wrote:
> > This is dependent on the microphone, preamp and sound
> > card in use, or for the output case, the soundcard,
> > power amp gain and speaker sensitivity (plus room
> > effects). 
> > 
> > You need to ensure that 120dbSPL at the transducer
> > does not clip either hhe mic, preamp or soundcard and
> > then find out what sample value this gives with your
> > hardware. Calibrate that point as 120dbSPL, then as
> > long as all your hardware is linear the rest of the
> > thing will just work.  
> FWIW, there is some work going on in ALSA to make the drivers use dB
> units for the mixer, rather than arbitrary scales.  But of course this
> will only work for devices for which the developers have the full
> hardware specs.
> Lee
It is a good news.

With jack, mixers as jackeq or jackmix are already using db scales.


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