The receiver can go all the way up to 99, so the 54 on Rock Band is quite low, especially if you want to hear yourself!
While those numbers may seem to leave you plenty of room to spare, they have little bearing at all om what the unit itself is actually putting out.
That depends on how strong the signal coming in is.
An amp can only put out so much power. Once it reaches that level, it triggers protective circuitry and shuts down. Most times it comes back on.
If the input signal is weak, you will have to turn it up to a high number to reach a the amp's maximum output. If no peaks go over the amp's rated output, all is well.
If the input signal is strong, you will can only turn it up to a lower number before reaching the amp's maximum output, and thereby triggering the protective circuitry. In this case, it doesn't take much to send the amp into it's protection mode.
Methinks the game puts outa fairly high voltage, at least at times, and sending the amp running for cover.
When jamming, one can get louder than they realize, particularly when everyone is trying to play louder thanthe next guy. Remember, you can't greate rock concert levels with tis sytem and if you're all rocking out, you just know you're eating up the watts.