On Sun, May 31, 2009 at 03:29:42PM +0200, Martin Homuth-Rosemann wrote: > I'm just working on this problem. It clicks because I switch the signals on/off > without every smoothing at random moments of the sine wave. I've changed the > timing to switch at zero crossings and the clicks go away. Looking at the schematics there is no evidence of any 'click removal' action. Also the waveforms summed there (for 4',8' and 16') would not be sinewaves. Each divider output has an RC lowpass filter before going to the mix bus. Assuming the dividers generate square waves, the smoothest waveform you can get would be a triangular one. What each of these RC filters does exactly will depend on the impedance it sees on the mix bus, and this is a complex function of the drawbar positions (*all* of them for each bus, since they share the resistors) and the number of notes already on. If the drawbar for a mix bus is at a low setting, or at maximum, its impedance would be quite low (the top end is feeding a virtual ground), in that case the RC filter frequency moves up, and there is a *highpass* action from the series capacitor and the mix bus impedance. This impedance reaches a maximum of around 5k for the third highest position. If two drawbars are the same position their corresponding mix busses are even shorted to each other. So just adding the contributions from each note does not correspond to what's happening here, both the amplitudes and the filtering of each note depend on almost the complete state of the instrument. Ciao, -- FA Io lo dico sempre: l'Italia è troppo stretta e lunga. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
