[linux-audio-dev] scaling jackinput to dbSPL

[Dominique Michel]

Le Tue, 15 Aug 2006 15:30:47 +0200,
conrad berhörster <conrad.berhoerster at gmx.de> a écrit :

> Hello all, 
> 
> Does anybody know, how i can scale the incoming jack signals to dbSPL, 
> which is in the range of 0 to 120. An is it possible to calculate from dbFS 
> (which is used in normal soundapp in range -inf to 12db)  into dbSPL. 
> 
> thanks c~
Look here:
http://en.wikipedia.org/wiki/Sound_pressure
http://en.wikipedia.org/wiki/DBFS
http://en.wikipedia.org/wiki/Decibel

The dbFS is an abbreviation for decibel amplitude levels in digital
systems which have a maximum available level (like PCM encoding). 0
dBFS is assigned to the maximum possible level.

The dbSPL correspond to the physical sound pressure level you have in a
given area. It can be in a range of whatever you want or can archive. 

It will depend on many factors and you have to measure it. And more, it
will be true only at the location you have done the measurement.
It you want to archive a constant sound level in a great area, you have
to use multiple speakers and amplifiers, and setup the volume level in
each amplifier with measurement of the sound level in different points
of the area.

Cheers,
Dominique