Ok. I only had the in game sliders set to zero so that would explain why audio would occur during the first tape and the boss fight.
I don't know if this is intended but if you have all of the game audio muted when you fight the final boss, it automatically raises the music. Certain loss events and bad ends also set the sound effect volume to 40%.
You need to attack her when you get the message that she is about to put you on them.
