Thanks, yeah I had to leave it at like -30 on the volume knob, nowhere near the +5 when the amp shuts down. I will do some more testing when I have more time. As you mentioned the m80's are a very stable 4ohm load, unlike many other speakers that are all over the place. For what I'm trying to research this will be adequate. I do have the Realtraps test tones from when I graphed my room acoustics, I may try that as well.

Thanks again, I will keep you posted.

No matter how stable the impedance is, it is still not a resistive load. The M80 have a complex crossover with both resistive and capacitive elements which will reck havac on your readings.