On Fri, 2010-11-12 at 15:47 +0000, Rui Nuno Capela wrote: > On 11/12/2010 03:08 PM, Eric Kampman wrote: > > Thanks. I don't understand the square root though. The equation is even > > more expensive processor-wise than the straight cos. > > > > the SQRT2 is a constant := sqrtf(2.0f), usually defined as M_SQRT2 in > "math.h" > > qtractor computes the panning coefficients each turn they get changed. > then it applies through regular gain to each steaming channel as usual. > just const mul over a vector/block/buffer, whatever > > > > > Granted, you're quoting someone else, but maybe someone out there knows. > > i'm no expert but i'm sure Ralf quoted me :)
Hi Eric :) you asked for the reason, why it's "wanted" to do this "cycles wasting" compensation. So first me, than this particular Rui ;): "On 01/25/2010 01:19 PM, Ralf Mardorf wrote: [snip] > * Panning for mono tracks, resp. balance for stereo tracks. The > "approximated equal-power effect" should cause nearly no > difference for the loudness of signals that are entirely to the > left or right, while other signals are in the centre, when > listening to a stereo mixing on mono. The relation of the signals > nearly should be kept. Is this right? right. stereo panning in qtractor follows an "approximated equal-power" trigonometric formula: L = SQRT2 * cos(pan * PI/2); R = SQRT2 * sin(pan * PI/2), where pan value ranges from 0 (full-left) to 1 (full-right). [snip]" http://sourceforge.net/mailarchive/message.php?msg_name=4B5DE06D.6020902%40rncbc.org I still could nag a lot about some issues I don't like regarding to Linux audio, especially regarding to MIDI ;), but I never noticed any issue regarding to panning for any app. Qtractor does a good panning. Resume: Audio engineers wish to have this loudness compensation, to avoid fading after panning ;). 2 Cents, Ralf _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
