You can bump it up in the AVR to around +5db or so at the highest. (that will mean the sub is 7.5db hot compared to your other speakers) Don't touch the sub amp's gain once it is set, otherwise you'll be shooting in the dark about where your levels really are. As long as you are listening below reference, you'll be safe. But if you are listening at reference or higher, you should back it back down to where your AVR originally set it. Keep in mind if you are running the sub 7.5db hot at reference, you are asking it to produce over 122db at your listening position...which it is not going to be able to do. You'll risk damaging it again. That is why I say back it down if you are planning on pushing it to reference or higher. For most people that is too loud for sustained listening anyway, and you are risking hearing damage if you listen at that level all the time.