Whoow , that was fast.... maybe i was a little bit misunderstandable. when i wrote about jack, i meant the jackserver. i write an app, which has an microphon input. now i will take this microphon signal and show it as a gain meter. this is no magic and everything works.
if i understand all of you right, the pressure on the microphon is something greater 0. and normally it is lower 2, right? first question: is this the same pressure which is measured in the literature in pascal (pa) if so, its easy to calculate out_value = 20.00*(Math.log(in_value/0.00002)/Math.log(10.00)); I know, i need to calibrate the room at the end. But in the moment, my question is simply to get a signal and show the loundness in dbSPL. Can i use the formula above or not? thanks c~ Am Dienstag 15 August 2006 16:09 schrieb Steve Harris: > On Tue, Aug 15, 2006 at 03:30:47 +0200, conrad berhörster wrote: > > 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. > > dB SPL is a measurement of physical sound energy, so in general software > was no control over it. It depends on the efficientcy of your monitors, > gain of your amps, desk etc. > > The only way you can relate dB SPL to dB FS is by calibrating your > particular setup using a sound level meter. There's a SMPTE standard for > the relationship between dB SPL and dBu or dBv (I forget which), which > gets you half way there, but noone uses it anyway. I had my home system > calibrated to SMPTE for a while, and it was just anoying. >
