CD Music issues

void soundManager::CDPlay(int track_number, signed int a3, int a4, int a5) is called, if CD-music is enabled, whenever the music track is changed. void soundManager::CDStop() is called upon exit, or when CD-music is disabled.

The current issue I am running into is determining when the CD-music volume level has changed. Naively, it would seem that void soundManager::CDSetVolume(int unknown_control_code, int unknown) is called upon a change in volume, but I cannot determine what the volume level is. unknown_control_code seems to always be 0xffffffff, unknown seems to be 0, and this->volRelated is 0xcdcdcdcd, I guess indicating it hasn't been written to yet.