I just spent a really beautiful spring afternoon indoors fascinated with running sweeps with REW. I know my initial measurements looked pretty bad at the top end and it left me with questions as to why. So, I reran Audyssey (twice) to be sure I had an accurate capture with it. I used 6 instead of my usual 3 locations.
What I found seems to be to be in conflict with how I believed Audyssey to function with the 'Reference Level Offset' setting. I believe the manual references it to be used with incremental increases for various material. Here's a screenshot:

So, what I found I would interpret to be the opposite. The +15 setting actually produces the flattest curve from my measurements. The 0db setting is the most boost at around 50/60hz and 15khz or so. That's not how I interpreted the description. I would believe 0db for movies would keep it the closest to the intention of the movie makers and compressed music would get the highest boost in the lows and highs to make it sound more dynamic than it is.
To the contrary - I got my best curve of the day (IMO) from running my Revel F35s full range with the Flat profile and Dynamic EQ on with +15db Reference Level Offset and without the sub. I tried almost every combination including running them full range plus LFE and Left Right Bypass. I attempted to set my sub (phase dial, placement) the best it could be according to measurements. I got better results without it unfortunately. It probably could be better placed, but my space is limited.
These were the fullest sweeps of left and right speakers from center listening position and about 6" left and right from center. I then merged those measurements. I don't yet know how it will sound. The big dip at 110hz is still there, but maybe a few db less severe. Its a couple db hot up top, but ends up basically flat to the rest of the curve at 20k. The extension looks pretty impressive to me compared to the rated specs of 55Hz, 46Hz, 35Hz (-3 dB, -6 dB, -10 dB).
Anyway, in case those previous measurements put anyone off I wanted to share this new best curve imo from my personal space setup. It might not sound the best, but it gets the flattest curve and now I know what I'm hearing when I tinker with the settings in the Denon AVR app and what is actually the 'flattest' that it can be (so far).
What I found seems to be to be in conflict with how I believed Audyssey to function with the 'Reference Level Offset' setting. I believe the manual references it to be used with incremental increases for various material. Here's a screenshot:

So, what I found I would interpret to be the opposite. The +15 setting actually produces the flattest curve from my measurements. The 0db setting is the most boost at around 50/60hz and 15khz or so. That's not how I interpreted the description. I would believe 0db for movies would keep it the closest to the intention of the movie makers and compressed music would get the highest boost in the lows and highs to make it sound more dynamic than it is.
To the contrary - I got my best curve of the day (IMO) from running my Revel F35s full range with the Flat profile and Dynamic EQ on with +15db Reference Level Offset and without the sub. I tried almost every combination including running them full range plus LFE and Left Right Bypass. I attempted to set my sub (phase dial, placement) the best it could be according to measurements. I got better results without it unfortunately. It probably could be better placed, but my space is limited.
These were the fullest sweeps of left and right speakers from center listening position and about 6" left and right from center. I then merged those measurements. I don't yet know how it will sound. The big dip at 110hz is still there, but maybe a few db less severe. Its a couple db hot up top, but ends up basically flat to the rest of the curve at 20k. The extension looks pretty impressive to me compared to the rated specs of 55Hz, 46Hz, 35Hz (-3 dB, -6 dB, -10 dB).

Anyway, in case those previous measurements put anyone off I wanted to share this new best curve imo from my personal space setup. It might not sound the best, but it gets the flattest curve and now I know what I'm hearing when I tinker with the settings in the Denon AVR app and what is actually the 'flattest' that it can be (so far).