Those are some serious speakers, producing a lot of bass. The manual has advice regarding placement
https://www.pmc-speakers.com/sites/default/files/attachments/web-Se%20Series-manual-July2022_0.pdf
I would:
1. make the 128 lb monsters movable
a. remove the spikes
b. I would prefer 3 wheels, two front, 1 rear center. dual wheel furniture casters have tight axels that do not wobble. 3 is more weight/wheel than 4; and 3 always settle without wobble wherever you put them.
c. OR add soft or hard ’skid’ plates to the bottom of the frame where the spikes used to be. felt pads on a hard floor, smooth plastic on carpet. move with force, stay put.
Now you have the ability to move them various distances from rear and side walls, until things improve. In current and any future space.
Doubt about movement/stability? See my system, my speakers on 3 wheels with Donna’s precious things on top of the angled enclosures. They move, they don’t move, nothing vibrates off the top. It’s about the correct ’tight’ wheels/amount of felt/amount of plastic (minimum material relative to speaker weight to allow movement)
9th photo shows bottom of speaker: (click FULL SCREEN top right, to see entire image/bottom of speaker/captions)
https://www.audiogon.com/systems/9511
flat 2x4 block on top of front wheels creates vertical angle when upright; 3 wheels (came on JSE Infinite Slope Model 2s. I tried ’superior’ wheels, all had wobbly axels, these dual wheel type are the best, no wobble when in position, with those 37lb 15" woofers doing their thing. Over 100lbs, they stay where I move them.
2. Alternate Toe-In
a. 1 listener: angle so each speaker is aimed directly at the listening position
b. 2 listeners, presumably a small chair in between, or ends of a sofa:
leave inside front corner where it is, rotate so that left speaker is aimed directly at right listener, aim right speaker directly at left listener. Imaging is ’maintained’ to a decent degree because each listener gets more volume from the opposite side due to directivity, as well as somewhat equal volume from speaker his side due to closer distance. It works, fiddle with it.
3. Angle the Speakers Vertically
so that they project the sound UP slightly. Ideally tweeter aimed directly at seated ear height. The combination of angled toe-in and angled vertically alters the direction and reflection of sound waves to and from floor/ceiling/side/rear walls.
In your case, anti-tipping solution(s) need to be solved.
4. Now, measuring tools to help find best location:
a. Sound Pressure Meter
On a tripod, at listening position, seated ear height
b. Test Tones to Measure (CD, not LP)
I use tracks 9-38 of this CD
https://www.discogs.com/release/7290000-Various-Amazing-Bytes
Single 1/3 octave tones, select;play/pause/....... not pink noise, single tones: make a chart, record what you are getting at your initial placement. Make copies, see what changes when moved .....? Take your time, take a break, back at it tomorrow .... Takes careful work, but you will save yourself the trouble/money/ugliness of a lot od room treatment. Perhaps some needed, but less for sure.
Live anywhere near me, Plainfield, NJ. It would be fun to help and hear those puppies!