Overkill for small room

Understanding how to operate a speaker management system which is a fancy term for a DSP unit, is really not that difficult. Their functions are pretty straight forward. The hardest part is training your ear so you can distinguish what you like from what you don't like and that just takes practice.

The biggest take away from all of this in my opinion is to figure out how to get your room under control. Once you do, your audio possibilities pretty much become, endless.

If you want to take a deeper dive into some of this stuff send me a PM. I would be more that happy to help.

I assumed I'd set up the speakers on the narrow end

I think that with your size room it would be better to place your speakers along the 11' wall. This will allow you to place both your speakers and your listening chair closer to the center of the room and away from the walls. You should try and keep a few feet if possible between your chair and the wall behind it.

The room will always be your biggest obstacle in achieving great sound. I would put most of my energy into learning how to either tune your room to your system (room treatments) or tune your system to your room (equalization) or a combination of both.

My room is 14' 4" x 10' 6" x 9'. I'm pairing small bookshelf speakers with 4) 12" subs. I play very loud aggressive music and I feel the highs are very clear and distinct, the mids are warm and natural and the lows thump but are not boomy.

I'm curious to know what you consider "very loud aggressive music.

Lately I have been listening quite a bit to Fear Inoculum by Tool.  I also like Orbital, NIN, Ministry, Big Black, Moon Duo, The Black Angels, Foo Fighters just to name a very small sampling, along with other genres like Folk, Jazz and classic Country.

And 4X 12" subs? What is your crossover

My main speakers are book shelf speakers, so two of the subs are slightly behind but in line with those, and those subs are low passed at 161 Hz using a 24 db Butterworth slope while the mains are high passed at 191 Hz using a 24 db Link/Riley slope which gives me a 6 db down point a little under 200 Hz. The actual down point and frequency will vary somewhat depending on the gain settings for the front subs and mains which varies from recording to recording. The other two subs are placed in an asynchronous (not the word I want but the only one I can think of right now) pattern in the room and are high passed at 79 Hz using a 48 db Butterworth slope. All four subs are high passed at 34 Hz using a 24 db Butterworth slope.

Are you feeding them with sub-outs or speaker-level?

My preamp connects to a XTA DP448  speaker management unit that handles the crossover duties, time alignment, gain setting, driver protection, and per channel input and output equalization if desired. I will never again use a speaker level sub connection.