I run a full set of Monolith THX 365/265 speakers with built in Atmos up firing speakers so 5.1.4 using all 9 channels of the X4500, the speakers are 89.5 db mains & surrounds 86db sensitivity and are rated at 4 Ohm.
I sit at around 12ft from LCR and with the X4500 at -2/3db they are plenty loud enough.I usually listen at around -10db to blurays etc and -20db for general tv stuff this room is my main living room in the house and is used 10hrs a day most days.
As you are closer (8ft) and your speakers are even more efficient I would say a PA is not
required unless you are wanting to listen at reference or close to ref (say -2/-5db) for extended periods most days. You could add a PA if you find your speakers starting to harden up at near ref, a PA should take away any harshness.
The only other consideration is room size if your room is enormous a pa would probably be needed. The room I have my kit in is 26ft x 16ft so fairly large by UK standards but you are in the US so your room could be much bigger.
For ref my main HC room is much smaller(14ft x 12ft) and I have a different setup in there as per my signature below. I use a PA with that rig because I like to listen at around -3db/5db max but like to really feel like the room is rocking and the 2 x 15" subs + a PA on the main 5 channels (LCR & surrounds) does that easily without breaking into a sweat.
So in short if you want to listen at ref/close to ref most of the time and your room is large and you can afford it spring for a PA.
These get good reviews and are cheap for what they are they do 5 and 7 channel versions. A 5 would do you for your LCR + main surrounds and use the Denon for all the other minor channels.
The Monolith™ 5X is a state‑of‑the‑art, high‑performance, audiophile‑grade multichannel home theater amplifier. Rated at a full 200 watts per channel into 8 ohms an
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