It didn't look like that review was overly scientific; to quote Alan in last Feb's newsletter,

"A simple claim of frequency response that cites two frequency extremes unqualified by a dB specification (e.g., frequency response: 34 Hz - 22 kHz) is meaningless and useless."
http://www.axiomaudio.com/archives/February2003.html

I've seen other independent frequency response graphs for the M60 and M80 and they were indeed within +-3db between 34 and 22k.

I'm not slamming hometheaterhifi.com in general, or saying what I've said is The Truth Of It (tm), but I think maybe there are different ways of going about measuring frequency response (some having more scientific grounding than others). I'd look around a bit more for more MFR graphs for the M60 and M80. Anyone have a link?

RD