Sets the base volume of channel's PCM Stream port. The range of "base_vol," which specifies the base volume, is 000H (minimum volume) to 007FH (maximum volume).
NOTE
Actual output volume of a port results from combining this function setting and the relative volume setting of sdPstmSetVol. Therefore, if this functions sets the volume to 007FH, the volume cannot be further increased by specifying a higher level with sdPstmSetVol().