[linux-audio-dev] db gain controls.

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. 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? James