4zb4 wrote
My interpretation was that his voice is so loud, it's actually sending shockwaves through the dungeon.
Which would be why it causes damage to anything hit by it, and why it's particularly good at breaking glass.
That's my interpretation too. I think the player is protected from damage by AV, but physically it might make more sense to make personal damage reduction dependent on material flexibility, as flexible materials could absorb more of the energy of the sound waves. Material strength would play a bigger part in object breakage (and probably does already).
Then again, similar arguments could probably be applied to a lot of damage types, depending on how one interprets "strength" and "flexibility" as material properties.