Graph of relationship between gain and distance in CoreAudio
Graph of relationship between gain and distance in CoreAudio
- Subject: Graph of relationship between gain and distance in CoreAudio
- From: "Timothy J. Wood" <email@hidden>
- Date: Sun, 15 Sep 2002 22:47:31 -0700
Just so no one else has to do this (and end up deaf -- should have
brought my ear plugs to work, clearly)...
I wrote an app where I could play a repeating sound (Basso.aiff from
the system folder) over and over while being able to tweak the gain and
distance (azimuth and elevation were always zero). The sound was
running into a 3D mixer component, configured for stereo output, using
vector panning spatialization.
I then put a digital sound meter in front of one of my speakers,
starting out with distance zero and gain zero and adjusted the volume
of my amplifier so that I got 90dB from the meter. Finally, I then
adjusted the distance in approximately 20 meter increments and then
upped the gain until I got back to 90dB (I gathered the min/max values
that I could set in my UI to make the meter still read 90 to help
offset error).
This produces the following graph:
http://www.omnigroup.com/~bungi/dB.png
My head hurts now... I also picked the largest dB I could stand to
help offset error :)
I haven't yet fit a curve to this, but that should be fairly easy.
-tim
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.