Quiet sound effects while in Crystal Tower

I did my first run of Labyrinth of Ancients yesterday, and for some reason all the sound effects, except my own, were incredibly quiet throughout the entire duration of the run. And i mean i could barely hear anything except from my own skills. If you'd have looked away from the screen, you would have forgot you were in a raid.

This doesn't happen anywhere else though, and i've been involved in killing S rank hunts outside Revenant's Toll, and i think it's safe to say that a lot more than 24 people turn up for those. Yet, while almost a complete mess because of the sheer quantity, the sound effects still come through.

I don't know if i'm missing a setting somewhere, or this is intentional design so that the game doesn't overload you with sound while in the Crystal Tower, but i was wondering if there was a way to fix it?

And, yes, I tried turning all volume down except sound effects, but everything still sounds really quiet.