void nuAuSndPlayerSetVol(s16 vol)
vol sound volume (0 - 0x7fff)
Set the volume of the sound object for the sound player. This is used immediately after the nuAuSndPlayerPlay function or after specifying the sound object using nuAuSndPlayerSetSound.
If the sound is currently being played back, its volume value is modified. If the sound is not being played back, it affects the volume value of sound the next time it is played back.