They are not really very loud noises, and it only lasts temporarily. Maybe I shouldn't say "hearing damage" but "ear damage", because I'd think that anything that causes you pain is doing something harmful to your body. Or maybe it's like exercising where your muscles ache for awhile and then heal resulting in increased strength? . "Gameboy soundchip improves hearing extra extra!" (but I doubt it, lol)
I never really measured the volume levels going into my ears, so I don't really know if it is simply the volume that is causing the sensitivity. I usually try to keep it at the lowest volume while still being able to hear everything but not always, especially with environmental noises. I was thinking maybe the specific frequencies were causing problems. The Gameboy probably has the "harshest" noise channel I've encountered in a classic game/vintage computer "soundchip". I wonder if the same effect occurs whether running lsdj on an emulator or gameboy with headphones (so far I've only done it with an emulator).
Now I am curious as to whether anyone else has used lsdj (or anything else) long and loudly enough to experience sensitivity to percussive sounds.
Edit: ah, I should have refreshed the page before posting :S