Hello Eric45,
JohnK is absolutely correct. Leave your receiver on the 8-ohm setting, otherwise the available power will be severely limited using a 4-ohm setting. And, like some other newcomers who've posted here, do not turn the volume control "all the way up" to test the output limits, as this may drive the receiver into clipping, which can toast your M80s' drivers with a distorted clipped signal.
If your receiver's volume setting is calibrated in decibels (dB), then "0 dB" is the approximate maximum output capability. Don't test it by cranking it to that setting.
Regards,
Alan
