[LAD] panning thoughts

[Philipp Überbacher]

Excerpts from Ralf Mardorf's message of 2010-11-13 14:17:46 +0100:
> On Sat, 2010-11-13 at 11:54 +0100, fons at kokkinizita.net wrote:
> > On Sat, Nov 13, 2010 at 09:07:35AM +0000, Folderol wrote:
> > 
> > > Why not go the whole hog and use a pre-calculated look-up table for the whole
> > > thing?
> > 
> > You only need to compute the L,R gains when they change.
> > Using a second order approximation such as the ones I
> > poster earlier is probably faster than a lookup table
> > in practice.
> > 
> > Here's one more:
> > 
> > p = panning position, 0...1
> > m = panning law control, 0...1
> > 
> > q = 1 - p
> > d = m * p * q
> > L_gain = q + d
> > R_gain = p + d
> > 
> > m = 0 -> -6 dB at center
> > m = 1 -> -2.5 dB at center
> > 
> > This takes three additions and two multiplications, which is peanuts.
> > 
> > Ciao,
> 
> Thank you for your explanations Fons :).
> 
> Is there a 'most common value' for the centre?
> 
> I do know several analog mixing consoles from el cheapo to very
> expensive and all pan pots are ok, I can't notice an audible difference.
> I only know one very el cheapo mixing console, the Yamaha RM 602,
> http://i1.tinypic.com/6fzx1k1.jpg , where the pan pots are crappy. As a
> youngster I started with this mixer :), using the pan pot means to
> readjust the faders ;).
> 
> Cheers!
> 
> Ralf

One thing I wonder about is the exact value of the center. I've seen
panning in software between -1 and +1 and a center of +/- 0 where it
made a difference whether it was + or -. It's easy to get confused by
stuff like that if you're a nitpicker :)