means "oscillate the sample volume using a
     particular waveform with amplitude y*(ticks - 1), such that (x *
     ticks)/64 cycles occur in the division". If either x or y are 0,
     then the old tremolo values will be used. The waveform is set using
     effect [14][7]. Similar to [4].

[8]: (Set panning position)
     This command is unused by the vast majority of trackers, but one
     tracker for the PC (called DMP) uses this for setting the panning
     state of the channel. As this is very useful