linuxaudio.org

On Fri, 2010-11-12 at 15:47 +0000, Rui Nuno Capela wrote:

quoted text
> 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]

quoted text
>    * 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...
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

Linux-audio-dev@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-dev