Ah, got it sorted: LEN=0 OFFSET=0 LPHASE=40 RPHASE=90 FREQ=.75 For mono file: sox in.flac out.flac remix 1 1 synth $LEN $OFFSET $LPHASE sine amod $FREQ $OFFSET $RPHASE sine amod $FREQ For stereo file: sox in.flac out.flac synth $LEN $OFFSET $LPHASE sine amod $FREQ $OFFSET $RPHASE sine amod $FREQ Jeff On Mon, 8 Jun 2020 at 08:20, Jeff Learman wrote: > Thanks. Actually I'll have both mono and stereo cases, but was asking > about the stereo case. Of course I can split the stereo into two mono > files. I was hoping to do it in one line, which was the real question here > -- the synth effect documentation says it can operate differently on > different channels but I couldn't figure how to make that work. > > Jeff > > On Mon, 8 Jun 2020 at 07:13, Dr. Thomas Tensi wrote: > >> 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@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/sox-users >> >