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Discussion Starter · #1 · (Edited)
We have an 18’ x 25’ home theater used primarily for movies that’s open on two sides to a 10,000 cu ft open floor plan. There’s a Danley DTS-10 for the front corner and we are looking to add 2-4 subs along the rear wall behind the listening positions. Last month, I joined the wait list to get four UXL-18 drivers with the current AVS group buy, and started looking at build options to maximize their potential.

The overall space dimensions are 49’ x 39’ x 8-12’ so room gain wouldn’t start until 11.5 Hz and only be about +6 Db at 5.25 Hz. Therefore, I’ve given up on trying to pressurize such a large volume at 10-15 Hz and would settle for really powerful near field extension and tactile punch at the primary listening position. The floor is concrete slab and there is no place on our current sofa frames to mount tactile transducers (Crowson Shadow-8 Duals might work, but we would need to buy 3 sets or raise the other seating to the same height). Space limitations dictate the subs can’t block an AC return vent, they must leave about a foot clearance for cleaning (we have dogs), and the enclosures can’t be higher than the sofa back.

OPTION 1 - Two to Four Matched Subs

We have room for two single driver enclosures at 27w 24d 32h to the right/left, and one dual driver enclosure at 64w 21d 32h (or two 32w 21d 32h back to back) in the center. Originally I intended to add only two right/left subs with the DTS-10 to save money. However, after listening to some AVS member systems I noticed that larger theaters were much harder to pressurize to create a tactile punch. It may take four UXL-18 subs with the DTS-10 to fill 10,000 cu ft to an adequate level.

I modeled all four subs from 15 Hz to 19 Hz matching tune in WinISD with between 2” to 3” slot ports and 7.6 to 8.1 cu ft volume, keeping the 1st port resonance between 140-150 Hz and the port velocity between 25-30 m/s. At 2000 watts from an Peavy 7500 or iNuke 6000, the UXL required a HPF between 13.1-13.4 Hz to limit Xmax to 34mm. There seemed to be the greatest overall efficiency at about 19 Hz. This is not as deep as I was hoping to get.

When I model the subs individually for more extention at 15-17.5 Hz, they loose 1-2 db between 20-30 Hz and gain 3-4 db between 10-15 Hz. The SPL is somewhat restored by the use of multiple subs (although I’m not sure if multiple ported subs gain +3 db per additional sub like multiple sealed subs; maybe they drop off below the tuning frequency because phase differences subtract from port gain).

The primary listening position is between 12” to 18” from the center sub and approx. 60” from the right/left subs so near field effect may allow exchanging SPL for greater extension and tactile feel at the listening position. The subs could all face out directly towards the seats to minimize room modes (4 points of origin), be mirror imaged to face each other to take advantage of gain from the rear wall and simplify DSP for phase response (2 points of origin), or some combination thereof.
 

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Discussion Starter · #2 · (Edited)
LA Audio Show 2017
 

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Discussion Starter · #3 · (Edited)
LA Audio Show 2017 - 2
 

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Discussion Starter · #4 · (Edited)
LA Audio Show 2017 - Part 3
 

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Can't offer much in the way of advice as you've already done quite a bit of thinking/comparing. It would require a lot of big subs and big wattage to pressurize that entire area, so I think your nearfield plan is a good one. With a DTS-10 and four UXL 18's you won't be exactly hurting for output (assuming you feed them enough power).

Looking forward to this thread and what you eventually wind up with. Good luck!
 

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based on recent conversations about horn modeling (w/diysoundguy), measured data coming out of data-bass (josh), and revisiting the lowarhorn, i would advise proceeding with caution with respect to putting a uxl driver in that cab.


while i don't think it would be a total fail or anything, target of light gray and best guess (at this point) black line, suggests you might not get exactly what you want.


 

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for your setup, four ported tuned to ~16hz is probably about ideal. that really should do it. :)


"When I model the subs individually for more extention at 15-17.5 Hz, they loose 1-2 db between 20-30 Hz and gain 3-4 db between 10-15 Hz. The SPL is somewhat restored by the use of multiple subs (although I’m not sure if multiple ported subs gain +3 db per additional sub like multiple sealed subs; maybe they drop off below the tuning frequency because phase differences subtract from port gain)."


jbrown15 measured his uxl ported cabs on the front wall. each time the number of subs was doubled, 1 to 2, and 2 to 4, the spl increased by +6db each time. his were at roughly 1/4 distance spacing on the front wall, so that may figure into his nearly ideal results.
 

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Discussion Starter · #9 · (Edited)
LA Audio Show 2017 videos

LA Audio Show #1


LA Audio Show #2


LA Audio Show #3


ELAC Andrew Jones Adante



Evolution Acoustics


Acapella


Sanders Sound


YG Acoustics


MagLev


Vivid Gyla G1



Von Schweizer Audio Ultra 11


----- (Axpona 2017)

 

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i'd tune them all similarly simply because phase changes quickly once you start introducing high pass filters and rapid changes in phase can create cancellations. i can't really speak to your other questions...
 
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