Tower Speakers Close to Back Wall

24” measured from the driver face is actually good for the bass, as bass is omni directional and the close boundary minimizes the 1/4 wave cancelation your get between 3.5’ and 6’ into the room. This is why you often see subs close to the front wall.

Towner speakers are rarely full range and some room gain helps them. The sound stage is what suffers with boundaries. The port is omni directional too. Rear ported just means it is closer to the wall than a front port.

If you get a speaker that has some bass roll off (99% do) a close wall boundary will flatten them out.

A used pair of Revel 226be are a good example of a speaker that could be placed close to a wall and not sound too bloated.

in the link below the last graph shows the same speaker in two different rooms. The home theater room has them out into the room (false wall) and the living room has them closer to the front wall. You can see how it effects the bass

https://audiosciencereview.com/forum/index.php?threads/revel-performabe-f226be-floorstanding-speaker-review.16702/

@flyfish77 Your room is a bit bigger than mine but I have 25-foot ceiling. Everyone told me that my speakers should not be too close to the front wall. I have them only 17 inches from the wall to the back of the speaker. The speaker has 12-inch woofers and lots of bass. I am not having any issues with fatigue or what seems like bad sound. My room is fairly naked with only some IKEA shelves for my kids toys. This room is not treated. It is the high ceiling and far away side boundaries that are saving the day.

You maybe able to put a lot of speakers into that space given what I observed in my room.

However, before I do anything with the speakers I would consider your gear before the speakers (your room is likely fine). I used to own the Matrix Mini i-3 Pro. It is the most versatile DAC I had owned but the sound quality is about a 7/10 in the scale of DACs I have bought. You can easily improve on that for low cost. The same on the Rotel amp.

Here is a 30-day home trial suggestion with your existing speakers. Get a PeachTree GAN1 and ideally a Sonore Optical or the much cheaper BluesNode package from PeachTree.

https://www.peachtreeaudio.com/products/gan1?variant=41609721020566

This is a very good sound. I have the GAN1 streamed with the fibre optic OpticalRendu. I also got mine modded by TweakAudio.com and it then was as good as $15k of gear I had in my office system. You void your warranty doing what I did but the cost was relatively low. The results are amazing.

A speaker is not going to make a weak source sound better. Even if you buy ’better’ speakers you are not feeding it a great signal.

BTW - I am comparing the GAN1 to a CODA @16 (currently own) and Benchmark AHB2 (maybe own again) amps.

BTW2 - I just saw you have subs. In that case, the BluesNode is what you would need to stream not the better OpticalRendu.

Consider Flexible Positioning

My room is smaller, but similar in use to yours, but my speakers are at the dining end of the room.

I have my heavy speakers on 3 wheels, so I can readily move them. Three wheels because more weight per wheel than 4, and 3 wheels don't wobble, put them anywhere, they find stability..

1. out several feet from side and rear wall, normal toe in for best imaging for single centered listener, speakers aimed directly at centered listening chair

2. same location, but alter toe-in for two listeners, maintain inside front corner, rotate left front corner to aim left speaker at right chair; right speaker aimed at left chair. Produces decent l/r sound, some sense of space and imaging; far better than hearing ’your side predominantly’.

3. pushed back into the corners, because the leaves are in the dining table for a large group. They sound darn good, and you are not concentrating on imaging or playing loudly so too much bass is not an issue.

My chairs are all ’transparent’ backs, the center ones rotate 180 degrees, to either listen to music or watch video.

see photos here

https://www.audiogon.com/systems/9511

I used/loved these JSE Model 2’s for many years until I went back to horns.

They come OEM with 4 dual wheel casters (dual wheel = tight axels). Easy to reposition from corner to ______

I changed the rear to 1 center wheel for prior noted reasons. Rear anti-tipping corner blocks are sometimes needed, normally 1/2" above the floor, but if the speakers start to tip, the corner block prevents that.

................................

They pop up for sale, usually under $1k from time to time.

Anyway, mobility is part of the original design.

These are quite dark, I think Walnut stained to look like Rosewood.

They come in lighter finishes, mine were ’normal’ Walnut, here is lighter finish, and you can see the wheels.

Some speakers, narrow front, deep enclosures can be positioned close to walls/corners, you need to research them

https://www.ebay.com/itm/126018211205?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=38688e5a-50d6-11ee-a5be-333334343561

Always watch out for ports, especially if near walls. Again, research of designer's intent is needed.

I am no fan of side/rear/bottom ports. If port, front facing is my preference.

You might consider a speaker that is designed to be close to the wall. Larsen comes to mind. 

This quickie search

Best tower speakers close to rear wall

popped up many images, might give you an idea which companies to check out

This is an area where KEF does really well.  The R5 towers will include three different port plug options- fully plugged, partially plugged or fully open.  

With these options you will be able to find the best bass for your required position.