The same 4db change is occurring with the Audyssey MULTEQ XT in 'Reference' or 'OFF'.
Don't think its the Audyssey. I could reset back to factory and check...
Just the act of turning the Subwoofer Level>Adjustment> 'ON' increases the level +4db...as I can HEAR it with my EARS.
The LEVEL/scale is set to ZERO.
If I turn the 'Subwoofer Level' 'Adjustment' to 'OFF' it decreases the sound -4db...according to my EARS.
Scale still set at ZERO.
In order to hear this I set it at -4db. Then turned it 'on' and 'off' and there was no change to the sound HEARD. Like I tried to show in that last pic.
Really just seems to be how this receiver works...as far as I can tell.
Not any kind of problem that I have with it, just explaining it I guess.
Was just an observation I made pushing buttons.
If I set either the top or middle dial to max on the subwoofer it would blow the windows out. Not doing that.
That pic is about as far as I ever ran it and it was plenty loud.
Also I think the difference in the old Denon and the new AVR is the hz level output, that old one just WAS, not any kind of adjustment. Bass/Treble/Volume, all I needed.

Just a guess but I think it was closer to 120hz. If that would make the speakers seem smaller shifting it to 80hz.
Another thing I hate about Sirius is those 3 women that just feel the need to talk and talk and talk.
Gunz/Kayla/Madison shut up already.
Blasting some good song then BAM! BLAH.BLAH...BLAH.BLAH...BLAH.
And
Lately its been having random half second break in audio...off, then back to normal.
Having troubles even listening to it. That little cut out really sucks. 3 times just typing this.