Hello Jeff, you wrote: > > [similar problem as amplitude modulating a sine wave] > I want to produce a stereo tremolo by using the sine amod > effect, out of phase on the left and right channels. I am not sure whether this can be done in one command, but you could modulate the channels into left and right mono versions and combine (merge) the file into a stereo file. I assume that your source is in mono? To paraphrase your solution: ----- INFILE=rd73_064__E4_082.flac OUTFILE=x.flac tempfileLeft=left.flac tempfileRight=right.flac LEN=0 OFFSET=0 phaseLeft=0 phaseRight=180 # sox command fragments tremPrefix=synth $LEN $OFFSET tremSuffix=2 sine amod 0.5 sox $INFILE $tempfileLeft $tremPrefix $phaseLeft $tremSuffix sox $INFILE $tempfileRight $tremPrefix $phaseRight $tremSuffix sox -M $tempfileLeft $tempfileRight $OUTFILE ----- Is this what you wanted? Best regards, Thomas _______________________________________________ Sox-users mailing list Sox-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/sox-users