2xs,
Nifty test.
Very methodical.
Did you try using the 6ohm and 8ohm switch to see if that made a difference?
It sounds to me like the DS989 hits a wall when powering the M80s.
In a sense, that is good to know. I probably will not change my M60s for the M80s anytime soon considering i have the DS797 receiver. In the future readers now know not to recommend that receiver for anyone considering the M80s for louder playback.
You should be able to sell your DS989 relatively easily and recover a fair bit of the cost, unless you have the option of returning it still.
Just in the past two weeks someone else had asked about HT receivers that would sucessfully power the M80s. Offhand i think some of the names were H/K av525?, Rotel, Sunfire Ultimate.
See if you can't find that recent post or wait for some suggestions from other posters who have already tried the M80s with some receiver combos.
