Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Linear/Log
SOUNDDATASUBCHANNEL_LOGParameter: Gradient Direction
SOUNDDATASUBCHANNEL_DIRECTIONParameter: Gradient
SOUNDDATASUBCHANNEL_GRADIENTParameter: Freeze
SOUNDDATASUBCHANNEL_FREEEZE