Your game has a DCS soundboard in it. Volume is controlled via pulse width modulation on the DSP.
Does the game issue any bongs when you boot it?
—
Chris Hibler - CARGPB #31
https://www.youtube.com/c/ChrisHiblerPinball - My YT Channel
http://www.PinWiki.com - The Place to go for Pinball Repair Info