Audyssey measures the -3dB point of each speaker in "your room" and reports that back to the Denon AVR. Denon and most other AVR's determine that a speaker capable of 40Hz should be set to Large, so it is actually the Denon that set that figure. In any case, I follow what most (including the mfg's of Audyssey) say that if you have a subwoofer in the mix, change those values to "Small" and adjust the crossover accordingly. For the M60's and 160 most likely 80Hz would be the best, but you could try 60Hz. I have my M80 and 180 setup to Small and 80Hz, but have experimented. I think my Q's are at 90Hz if I remember correctly.
