Re: Mixer units
Re: Mixer units
- Subject: Re: Mixer units
- From: Brian Willoughby <email@hidden>
- Date: Tue, 11 Mar 2003 13:44:34 -0800
[ > From: Bill Stewart <email@hidden>
[ >
[ <snip>
[ > We haven't implemented panning for stereo sources..
[ >
[ Is panning stereo sources really hard?
Perhaps it isn't hard, but there are many different techniques for designing
pan pots - more than you might think.
Panning a mono source to stereo is probably best with a curve that is 3 dB
down in the center position. However, typical room acoustics are not precise,
and the signals from each speaker may not precisely combine, so using more or
less than 3 dB might be better.
Panning a stereo source is usually implemented such that each channel is
completely unaffected in the center position. Turning the knob left will
slowly attenuate the right channel, and vise versa.
Another issue to consider is that you might not ever want a channel to
completely go silent, since this is not natural sounding in headphones.
I recently attended the local AES (Audio Engineering Society) meeting devoted
to the decibel and audio perception. During this talk, I learned that some DJ
mixers actually drop more than the usual amount in the center position,
especially for the cross faders, because two beat synced dance tracks tend to
have lots of in-phase signal, and there is less clipping if the faders drop the
signals a little more in the center position. Unfortunately, I did not take
notes on the actual dB drop that was measured and mentioned.
The design behind pan pots and cross faders is something that I've never seen
documented on equipment, but there are certainly a wide variety of
implementations. Given the right equipment, someone could measure various
popular mixer products on the market, and "steal" their dB pan/crossfader
curves.
So, it might not be hard to *implement* stereo panning, but it may be quite
difficult to deliver something that everyone will like.
One idea I would like to see implemented is a pan/crossfade control which
allows selection among simulations of the different curves in use on the
physical world.
Brian Willoughby
Sound Consulting
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