It seems that using game.speech_music_drop = 0; will still cause a minor drop in music volume whenever speech plays, using v3.2.1 of AGS. Should I be doing something differently?
Aside from game.speech_music_drop (which may be considered obsolete since 3.2, I think) there's also "VolumeReductionWhileSpeechPlaying" option per each Audio Type. The default for Music type is 30.
That works, thanks.