Digital Room Correction vs Room Treatments

You have a very attractive room, small but certainly capable of being tamed with a pair of subs and a large bass trap. A small room needs lots of absorption, a large room needs lots of diffusion and a mid sized room needs some of both.

As I mentioned in an earlier post you could use the sub as a coffee table but the photos reveal 2 obvious places that will not only not get in your way but are generally from the many installations I've done the preferred positions.

First Sub: On the left wall below the window and tucked up close to the record rack.

Second Sub: Behind the couch slap in the middle of the back wall.

The obvious place for a bass trap is horizontally on the back wall where you can accommodate a full size superchunk design. See photos below, only you would build it horizontally.

I also suggest you take 2 or 3 of those slim grey panels and fix them to the door and replace them with 4" thick broad-band absorbers. To help further, consider adding heavy drapes/curtains across the window. They can be drawn aside of course but closed when needed.

Your main speakers' bass output will naturally contribute to the chaotic bass propagating around the room and by moving them only small amounts can fine tune the resultant response. Just a couple of inches.

The lone speaker at the back can be left right where it is but you should short out its speaker terminals with some wire. This will damp cone motion from pressure waves causing the speaker to act as a microphone and driving power into the crossover then releasing that power out of phase and time with music

Having the main speakers overpowering the room is a fallacy. With the room acoustics sorted this is not an issue.

Regarding your post above, changing speakers are not going to sort out the issues you are experiencing. Prove this to yourself by plugging the ports on yor main speakers which will effectively render them as sealed boxes and have the bass response roll off earlier at 12dB/octave. This will immediately show up on REW and it costs nothing but a little of your time, it's also informative. There is no need to settle for a ragged response. In one of the photos you can see a DIY absorber that is usually 4" deep but I made these 5" deep for them to work lower in frequency. My wife said she does not want me to go 6" deep.

You can also build a ceiling cloud to suspend from the ceiling which is very effective. Use REW to check your decay times as I mentioned in a previous post. This is a scientific approach to sorting out a room's acoustic problems which each and every room suffers from regardless of shape or volume. Fact.

Start of bass trap left front corner.

Bass trap waiting for cover to be attached with velcro.

Bass Trap right front corner finished with cover on and heavy drapes visible

@lemonhaze Great suggestions, thanks so much!  
 

I’m assuming modest sized sealed subs would do for a room like mine.  I see REL subs favored by a lot of audio people.  Is this what you’d recommend?

Whay type of fill do you use for your triangular traps?  And you’re saying build it horizontally and put it above my wall cabinets across the entire back wall at the interface between wall and ceiling?   And you’d go as thick as I could go, up to and including 6” if I can swing it?

Yes build the traps as shown across the entire back wall. The colourful panels in the photos are DIY broad-band absorbers. Google has dozens of how to DIY examples. You need a few. And consider heavy drapes across that window.

See dimensions for bass trap construction from a previous post of mine, it's all there so no need for me to repeat. Once again google for DIY superchunk bass traps but do not go smaller than the sizes I provided. You will measure and hear the benefit and it's not small.

First off, if you want to be able to place the subs where you won’t fall over them then forget REL or any other sub that does not provide adjustable phase. REL subs only provide 0 or 180 degrees.

Let’s now look at that huge 35Hz peak caused by bass waves combining ’in phase’. Think of waves traveling towards the beach and remember how when secondary or tertiary waves catch up with those in front you get a larger wave form. That illustrates waves combining in phase, OK?  So the exact same thing is happening in your room and it’s happening at 35Hz.

What if you could magically provide an antiphase 35Hz signal? problem solved, right? Well you can do exactly that by adjusting phase, SPL, crossover frequency, crossover slope, room gain and PEQ.  You can tame the peaks and fill in the nulls. Sub number 2 will smooth things more.

Your speakers have ports so as an experiment plug them and see what happens to the response on REW and report back. There will be noticeable change,visually and audibly.

Before you spend on Dirac Live get yourself 2 x SVS SB 1000 PRO subs for about $600 each. Buy, beg or borrow. Adding subs does a lot more than just smooth the response, there is a performance gain across the spectrum.

As mentioned it’s not only SVS that can do this, many others available but the ones I suggest are IMO best value. Small compact units that also provide the remote App to allow adjustment from you armchair.

I have a 5m x 7m room opening to the kitchen and my small REL @#$$% and SVS fill my room with effortless detailed bass. The only reason I don’t have a 3rd sub is because we are going to sell the house.

I mentioned reading papers from Geddes, Toole and Welti. I strongly encourage you to google them up and read and learn from them.

BTW - if you are a ROON or JRiver user then Mitch's Convolution Filters are easy to use.

Honestly too hard and too much.  Simple parametric EQs  in Roon will solve the OP's problems.

Here is a plot of my room:

As you can see it looks a little bit better than yours. No 35Hz peak. The aberration between 100Hz and 250Hz is because I am not able to vary phase on the REL. The point being you will be able to get an even better in room response than mine by following my advice.

The above complies with the industry standard of +/_3dB up to the Schroeder frequency, the modal region.

Contrary to the advice above PEQ in Roon can not solve the overlong in-room decay, you need absorbers for that and PEQ does not absorb. How can it possibly know what frequencies need absorption and by how much. REW is the tool to help with that.