Oh, they just sound better at higher volumes, simply because it's easier for the human ear to hear all the frequencies when they're not all turned down.

I don't have M60s in my house (never have), but the M80s are a significant improvement over M50s at all volumes. I hear what you're saying about low to moderate volume--that's pretty much where the M80s live, unless my wife is out of the house or she's watching NCIS.

I am the Doctor, and THIS... is my SPOON!