That is a very nice room. \:\) You don't mention how you have your receiver setup/calibrated. Hopefully, you have the other speakers set to "small" with an 80hz crossover as a starting point.

The 60's will give you more dynamics with the additional tweets/mid's/woofers and the larger cabinet will produce more bass in the room.

The receiver should be fine. Have you run the built in Audyssey Mult EQ on the Denon from multiple locations?

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