Yes, that's true. I have my 600 and the Denon set to 60Hz. 80Hz is too "thick" and 40Hz is too "thin" on the 600. I told Randy last week that I had the x-overs at 40Hz but I checked and they're both at 60Hz.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated