James Courtier-Dutton <[EMAIL PROTECTED]> writes: > Hi, > > I have a question for some audio professionals out there. > What is the smallest sensible gain control step in dB. > Is it 0.5dB ? > I am asking, because if one is using a digital gain control in a 24bit > fixed point DSP, once could use almost any step size, so I am looking > for the smallest sensible size to use.
Well, the minimum possible difference for 24bit is between -2^23+1 and -2^23, and that would be about 0.000001dB. > Some people mentioned earlier on a previous thread that there was > something called soft gain control, where the user moves the gain up a > step, but the mixer gradually(fairly quickly) adjusts the volume to > the new level, so no clicks are heard on the speakers. How does these > soft gain controls prevent the clicking? Do they wait for the zero > crossing point to adjust the gain? No, why should they? You just ramp up the volume linearly. If you want to be even nicer, you use a shape that is even smoother. Basically, you put the step pulse from the jump gain through a low pass filter, preferably one that does not overswing. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum
