This may not help you with Audyssey but it may help you with sub set-up.
I have an Epic80-600 and I've had one heck of a time getting "tight" bass in my 4,000 cubic foot room. I've been experimenting the last week and have found that by setting the cut-off in my Denon and on the 600 to 40Hz, I can achieve very tight bass. I also found that I had to turn the gain control on the 600 to about 7 o'clock and the gain on my Denon to 0. My previous settings were 10 o'clock, -7 on the LFE channel, 80Hz on the Denon and by-pass on the 600. The full setting works best for my case.
I find that when I turn the gain knob of the 600 up, the bass has too much "overhang" (technically called a long settling time). But I don't have the same problem if I turn the Denon's LFE gain up.
To really experience this tightness, I have to turn the main gain of the Denon up (over 20W/channel). This is extremely loud in my space and I can only do this when everyone is out. But with the previous sub configuration, even when I turned it up it wasn't tight. It was just more full.
Blending between the 600 and 80s is the same...astounding! However, I have lost some "transparency". Prior to doing this, string bass lines had their focal point in the front of my soundstage but nonetheless "floated all around me". Now, I don't have that "bass everywhere" feeling. This just convinces me even more that I can't have bass tight and transparent...at least not in my space.
By the way, this 40Hz setting is great for music and movies. I have found that in scenes like explosions and gunshots, the bass is not as full but it hits very hard...much harder than 80Hz. The criticism to this of course would be that I am missing some action from my QS8s between about 40Hz to 70Hz but I haven't found this to be a problem practically.