<sid_number> is optional and defines on which SID chip the filter values should be set. If it isn't provided, it defaults to 1. This parameter is useful on multi-SID systems, for example a C64 equipped with two SID chips, or the M65 that has four SID chips. The number must be between 1 and 4.
<volume> is an expression that evaluates to a number between 0 and 15.
Examples
' Set maximum volume
VOLUME 15
' Make SID #2 silent
VOLUME 2, 0
Note
On X16, volume for each voice can be set individually. See VOICE.