Subwoofer matching

My experience with matching subs to just about any speaker is to go with an array of multiple subs rather than just a pair, as others have correctly observed.  The idea is to have a large wave launch that can match the volume level of the much faster, smaller drivers without having to push them hard.  If you have you ever heard the Infinity IRSs they are a good case in point, as the ribbons in that array are extremely fast.

I have AG Trios and they came with a two pair of dual 10" inch powered subs.  That combination was just barely OK, and tended to fall apart at higher volumes especially with rock music.  I suspect that is why AG came up with the idea of horn subs, but those beasts are huge and expensive.  I solved the sub  problem by adding another pair of dual subs, now 12 total and it was trans-formative, not perfect but much improved.

You might want to consider just picking up two pair of used 225s.  They are relatively inexpensive on the used market.  Also, I agree with Mijostyn's comment regarding speed and subwoofer size.

REL customer service recently told me they won't repair either of my subs should they ever need it. Hmmm...also, "speed" is a silly term and I don't think it's applicable to subs or really anything else in audio. I think some bass overhang in reverberant environs might be what makes people think there's a velocity issue, and many think it comes from cone material...it doesn't.

I am in the same camp as those that say quantity of subs is more critical than quality.

I have four subs in my system made by three different manufacturers.

"...also, "speed" is a silly term and I don't think it's applicable to subs or really anything else in audio."

Perhaps in your opinion and in your experience, but not in mine. I have tried various different combinations of three powered subwoofers; 12" and 15" - one 12" I own in a different system and the other two borrowed from friends, with my Omega Super Alnico Monitors, and in all cases I felt the subwoofers could not "keep up" with the single drivers and there was an obvious tonal lag in the portion of the bass delivered by the subs. I and the man who designed/built the Omegas express this phenomenon as "speed", others might call it something else. His recommendation was to use subwoofers either with two 8" drivers in a sealed box or multiple 8" (or at most 10") driver sealed subwoofers.  Call it whatever you want.

got 80 cubic feet?

https://www.ebay.com/itm/6-Electrovoice-30W-sub-woofer-speakers-for-tube-amplifier-audio-western-ele...

a swarm, 6 x 80 = 480 cu ft!