On Tue, Mar 12, 2013 at 01:23:02AM -0400, Tim E. Real wrote: > I noticed our app uses this pan formula: > > vol_L = volume * (1.0 - pan); > vol_R = volume * (1.0 + pan); > > where volume is the fader value, pan is the pan knob value > which ranges between -1.0 and 1.0, and vol_L and vol_R are the > factors to be applied to the data when sending a mono signal > to a stereo bus. > > When pan is center, 100% of the signal is sent to L and R. > At pan extremities, the signal is boosted by 3dB.
6 dB actually. > But according to [1], we should be using a Pan Law [2], > where pan center is around 3dB to 6dB down and pan > extremities is full signal. There are two independent issues involved here: 1. The attenuation at the center w.r.t. to extreme L and R. 2. Whether the center or the extremes should be 0 dB. (2) is very much a matter of taste and of virtually no practical consequence : you will adjust the fader (channel gain) to get the right balance anyway. Regarding (1), if you take psycho-acoustics into account you'd want -6 dB at the center for low frequencies and -3 dB for high frequencies, with a gentle crossover at around 500 Hz or so. So the SSL compromise of -4.5 dB makes sense. Note that unless you use the panner to move a sound around during a mix, all of this hardly matters: you will adjust the balance anyway and compensate for whatever the panner is doing. Returning to (2): for a panner (mono -> stereo) I'd prefer 0 dB at L and R. For a balance control (stereo -> stereo) I'd prefer 0 dB at the center position. -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
