I've never been at a rehersal where people don't use some form of hearing protection if there are drums involved, and I/we don't play that loud at all.
In my bands:
- Drummer A: Uses either plugs or IEM's (for a metronome when needed)
- Drummer B: Uses decent noise cancelling headphones. Also he needs to hear the backing tracks.
- Everyone uses at least some form of hearing protection.
- Band A's guitar combo is elevated, Band B's half-stack is well positioned and kept at rational levels.
Every now and then we do a soundcheck/volume check of sorts, just to keep our levels balanced and the volume at a rational level etc. Drums and vocals -> add bass, guitar and synth -> balance it -> drop all the levels a bit.
To me it sounds like the drummer's just being a brat. Good or at least decent plugs/IEM's/headphones(/ even cotton balls ffs.) are relatively cheap and there is no solid reason to risk damage to your hearing. If that's too much to ask, I'd just let him go.
(I've got tinnitus, definitely not as bad as it could be, but annoying enough. Seeing/hearing about people who don't protect their hearing at all pisses me off

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