Subwoofers is 5 is the Magic number?

First I have a terribly small listening room 15 x 17 x 8 foot tall feet with a large 7 foot by 7 foot opening on one side and large glass windows on the other side.

I really dont have any room treatments other than my Australian Sheppard that tends not to move when Im in critical listening mode. I have been adding subwoofers to cancle or excite room nodes and act as room treatment via cancellation or addition.So far its been a mixed bag from Epic failure, to Damm that sounds good but not real, to Hey that sounds about right!

For me I am now settled in with 5 subwoofer's. I have read for years that room acoustics is at least 50 percent of what you listening to and now I understand all the old post Ive read. Oddly enough the 6th made Subwoofer made it sound worse no matter what I tried. Possibly  a 30HZ hard cutoff would work not sure. The 5th Sub is in the most ridiculous position ever at the top of a 80 inch tall Armoire aimed at the ceiling. lol. Im running 4 of the subs in stereo front and rear all the same subs at the same volume and crossover (with volume pots for left and right) via a stereo AMP designed for the subs with one lifted 28 inches off the floor in the classic "Getty distributed bass array configuration" and the 5th Subwoofer in mono summed left and right with a dedicated amp. This is sounding best so far. I have a mini dsp that Im about to add to the mix. My Pass Aleph P pre amp allows me run the main speakers via XLR (not high passed / full range) and the Sub amps of the RCA's concurrently.

Side note I just bought some Pangea cables from Audio Advisor their SE edition for both the XLR and RCA's. Props to George Cardas Very nice cables for a reasonable price. I also am from AZ so I love the finest Copper in the world from AZ they use as marketing propaganda ... haha. They are made Build quality is excellent and sound very good for the price.

-ALLGOOD