[LAD] Mixing audio: Noiseless volume changes

[Tim Goetze]

[Fons Adriaensen]
>Exactly the same with the form I proposed, w, a, b need to be computed
>just once, not for every gain change. In fact only w depends on the
>sample rate, a and b are fixed constants. 

Ah yes, sorry, I see that now.  

If that extra operation comes around to bite hard enough, I'll be sure
to chain two 1st-order lowpass filters.