You know I've ran separate enclosures forever. My monitor sections (300 hz >) are separate from my Mid bass couplers, and MB couplers (80-300 hz) are separate from my bass (80-100 hz <) units. I keep the MB very close to the monitor section. I like a narrow baffle for the monitors, and as narrow as I can get with the couplers. I'm a VMPS fan from WAY back, and of course there are those that think VMPS was NOT a good speaker. It's ok to be WRONG. They were and ARE a well built speaker and have a true CULT following. I'm ONE... BUT I'm not a VMPS only kind of guy. If you read any of the stuff I post, just about anything goes as long as it is in the interest and PURSUIT of "THE SOUND"
That guy Brian C. Mr Bass, wasn't your normal, follow the leader, kind of guy. I LIKED the guy his "try it see if it SOUNDS right approach" was just despised by a few of his (they thought) competitors, and a watchful eye from most of the others. He sold finished speakers, kits, raw drivers, and for a few he built OX, OXO, all kinds of goodies.
The kits, the drivers and just about everything was upgradable. RARE!!
The real rare part, IT WAS AFFORDABLE, Very affordable. The guy was on the way home, for over 30 years. 30 years of stopping in seeing all kinds of ideas. One of his bass enclosures, was set up with a 12,15 active, 15 passive (tunable) 250 < (some 350 <) had to ask for the latter.
Was designed to blend in some type of very popular speaker at the time. Quad or something..
THAT is when he said, "if not for expense", There would be 2 (3 if subs were used) enclosures in his systems. COST!!!! I went to 2 enclosures per side, and depending on the music and the BASS two or more < 100 hz enclosures were added. normally behind or mid way in the room.
That is when I learned TIMING (moving the enclosure forward or backward), the length of the wave, where it's coming from, and bouncing off of, was the key to BASS, if you can control 300 < everything else is pretty easy. I learned that PHASE PLUGS, were the key to distortion in the bass sections, if a servo system wasn't used.
I use HUGE couplers, 4 12 WCF phase plugged MB couplers. That surface area is large and very much influenced by 100hz and down. PP took care of the problem mechanically, without a processor.. HF issues, room treatment, mids, position (more so), and BASS well it's everywhere, so EVERYTHING counts, ay.
I'm currently reducing the size of the couplers and increasing the number to narrow the baffle. 4 enclosure (may add a third per) with 3 8" PP drivers per enclosure. In theory it's suppose to be better, we'll see. Then the newer servo bass system has a little more leg room. 100-120 hz or lower. VERY VERY clean bass reproduction. Very analog. I also use enclosures that use PR with mass tuning, like down to 177 BB size of tuning. Brian taught me how to FINE tune bass without processors, in spite of a shi? amp, pre amp, room conditions, everything.. He was incredibly blessed with "THE EAR" for that...Not easy to do, takes me days to get it right.
That is a lot of enclosures per side, but it sure WORKS. and easy for me to tune, just an inch here and there, with a monitor swap..Wife appeal, well she is a pretty good sport, especially when she's not here...
A lot of folks have listened, a lot of folks leave with a smile and a "how the heck did you do that"? See it's not the normal way of doing things so many purest just thumb their noses. It's ok it's your nose, it's my ears..LOL
Respectfully, and with regard, the OldHvyMec