Comment to everyone who reads this: I highly recommend custom made earplugs to anyone who plays in a band and/or likes going to concerts. They are not cheap, but your hearing is priceless.
Because of the physics of sound waves it is impossible to create ear plugs that attenuate all frequencies equally. High frequency sound waves are weaker than low frequency waves, so you will always have higher attentuation in the higher frequencies. Result = too much low end, no definition.
Also, you are used to hearing your own voice at a certain level, or even amplified. When you use earplugs you will hear your voice in a way that seems unnatural to you, no matter how good and expensive the earplugs are. You'll get used to it after a while.
If you simply can't get used to it, the only other option I can think of would be to get in ear monitors. That way you block the extreme high volume sound from the band, but get a nice feed through your earplugs at healthy levels.