--- conrad berhörster <conrad.berhoerster(a)gmx.de>
wrote:
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));
Its not a case of calibrating the room, its basically
a case of needing to know what sample value 20uPa
equates to.
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.
Regards, Dan.
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