Vibrato
Where [4][x][y] means "oscillate the sample pitch using a particular waveform with amplitude y/16 semitones, such that (x * ticks)/64 cycles occur in the division". The waveform is set using effect [14][4]. By placing vibrato effects on consecutive divisions, the vibrato effect can be maintained. If either x or y are 0, then the old vibrato values will be used.