[LAD] Mixing audio: Implementing pan and balance

Hi, I need some advice, clear up some confusion: 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. 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. So I want to change how we mix mono -> stereo and use true Pan Law. I could add a Pan Law selector, seems like it might be useful for various studio acoustics. Then I noticed we use the same formula above to apply 'balance' (using the same pan knob) when sending a stereo signal to a stereo bus. But according to [3] we should be using a true balance control, not those same pan factors above. And according to [1]: "Note that mixers which have stereo input channels controlled by a single pan pot are in fact using the balance control architecture in those channels, not pan control." So I want to change how we mix stereo -> stereo and use true balance. But then I checked some other apps to see what they do. In an unofficial test I noticed that QTractor seems to do the same thing, that is, when pan is adjusted on a stereo track, one meter goes up while the other goes down. RG seems not to have stereo meters and Ardour I couldn't seem to make pan affect the meters, I will try some more. My questions: Is the pan formula above popular? What is the consensus on stereo balance - use a Pan Law, being the formula above or otherwise, or use a true balance? What should I do in the remaining case sending a stereo signal to a mono bus? If I am using a Pan Law as balance, the two signals will have already been attenuated at pan center so I could simply sum the two channels together. But if instead I use true balance, at center the two signals are 100%. So should I attenuate the signals before summing them to a mono bus? Currently as our pan formula above shows, there would be no attenuation. Thanks. Tim. [1] http://en.wikipedia.org/wiki/Panning_%28audio%29 [2] http://en.wikipedia.org/wiki/Pan_law [3] http://www.rane.com/par-b.html#balance