As always, thanks for the info
I certainly didn't expect a big difference, but was trying it out of curiosity more than anything else.
I think I've got the rest of the receiver settings dialed-in exactly how I want it. Reading (and re-reading) this, and the other 'official' Denon threads has helped *immensely*. Re-adjusting my subwoofer settings last night by lowering the gain on the subwoofer back to the 12 o'clock position used during calibration and increasing the LFE channel level instead has made a noticeable audible improvement in terms of smoothing out the bass response.
BTW, I think it was a smart idea consolidating all the Denon threads for the XX12 models, as many issues encountered are relevant between model types.