Something a bit more extreme... BIG Subwoofer!

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#1
With the last 2 additions of the Arrakis & SubMersive theater and Art Sonneborn's system, I saw that we were lacking some in the fun, extreme stuff, especially in the subwoofer department. As you might imagine, this and a few other projects had greatly cut into the time I had to visit this forum. I intend to be more involved here in the future. Hopefully a few find this of interest...

These pictures show what went into the build and installation of a custom project commissioned by Keith Yates to serve as the "UberSub" in a very impressive room that is a start-to-finish, Keith Yates Design Group project. I posted pictures of this project to our facebook page back in June when I delivered the subwoofer at the white room phase of the project (prior to acoustic treatments and fabric), where they test for construction integrity, noise isolation and modal behavior against the extensive modeling done in the design phase. Next week the project will be complete and the calibration will be done. I will have a few more photos of the final result after next weekend when the owner hosts an open house for all of those who worked on the project.

As more than a few already commented to me... "Finally, a speaker that really CAN blow womens clothes off!" :eek:

Really, I'm not a midget, this beast is 7' tall, 600 lbs., assembled from 5 pieces and was then set on a platform remaining from the original foundation in the corner of the basement:


Some perspective of what goes into such a beast:

Quite the assembly of stainless steel hardware for this custom built uber-subwoofer... Just the hardware shown plus the threaded inserts total more than 20 lbs. Of course 20 lbs isn't much in the scope of a ~500 lb subwoofer. One of my employees Mike insisted the PBR gave a better frame of reference than the coffee mug, and they are rather appropriate bookends for the hurdles involved in engineering and assembly this beast. For further scale, the long machine screws above are 1/2" thread, 10" long.

--

Starting to put all of the previously pictured stainless steel hardware to use... I had OD'd on the coffee at the time this pic was taken so we have a Cherry Coke in there for scale. This is just one part with 3 others like it and a main housing which assemble into the 600 lb monolith seen above. Around this point I started referring to this design in house as the Devastator.


Here we see 1 of the 4 assembled modules which power this monster... each weighing more than 95 lbs!


Complete modules staged next to the main enclosure.


A quick test fit checking alignment of the first module.


The huge, 10" long, 1/2" diameter machine screws from above are hand threaded to confirm everything aligns.
<insert sigh of relief> :p


In fact everything lined up just as designed, combining the 5 parts to the massive monolith.


A good friend Tom answered a frantic call for reinforcements, especially outside normal hours when I wouldn't have additional hands around. Here we were admiring our work and how outrageous and comical such a monster seemed fully assembled.


750 miles and a short carry later, we had the UberSub's 4 modules and main enclosure in the room and re-assembled. Erecting the 600 lb monolith felt a bit like an exercise in uprighting a section of Stonehenge. The tall risers for the various rows came in very handy, sparing us a cumbersome dead-lift. Here you can also get a peek at the massive flaring on the port which allows extension to and just below 10Hz.


After up-righting this beast, not only did we have to move the subwoofer into place, but that place was ~16"above the ground on a concrete ledge about the same depth of the sub. This manual crank lift made it possible, but still required some rather resourceful maneuvering to get it placed on top of a non-slip pad and backed up to the wall. Another Stonehenge like moment...

In the above picture you can also get a glimpse of the ramp running across the back of the room and around the right of the rear riser. The owner of this theater is wheelchair bound, and wanted a real theatrical and music sanctuary for him, his family and friends. No one driving by the home would suspect such an engineering effort to be hiding in the basement. :cool:

After lots of effort and head scratching, the UberSub is in place and ready for testing. Once testing was completed and the expectations verified, the rest of the room was set to be finished with the many acoustic treatments which will all be hidden behind fabric, including this monster subwoofer.


More to come after the open house party!
 

Steve Williams

Site Founder, Site Owner, Administrator
#2
Great project Mark

Are those 18" drivers in the sub

Nice to see you in our neck of the woods again
 

LL21

Well-Known Member
Dec 26, 2010
11,502
478
628
#3
Impressive! Thanks for sharing! how do you blend these into the rest of the system?
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#6
What? Not stereo?!?! :D

Awesome job, Mark, can you publish specs?
Thanks Don. Being a custom, commissioned project I won't post exact details, but the little bit of testing I was present for indicated capability of around 125dB at the main listening area above 18Hz, with useful extension down into the 8Hz range. What you see is roughly 30" wide, 20" deep, and 7' tall. The monolith is powered from the equipment rack by a single chassis, LabGruppen FP 1000Q amplifier.

This is what Keith designates as the "UberSub" in a design which uses many JL audio subwoofers distributed around the room per their BOSS optimization process for the subwoofers.
 
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Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#7
Impressive! Thanks for sharing! how do you blend these into the rest of the system?
Once all of the acoustic treatments are in and fabric goes up, the system is optimized using a custom Trinnov processor. Despite its size and depth in extension, the upper frequency limit is still ~80Hz. Combined with the 12" & 13" JL subwoofers in the room I expect rather impressive results. :)
 
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LL21

Well-Known Member
Dec 26, 2010
11,502
478
628
#8
Once all of the acoustic treatments are in and fabric goes up, the system is optimized using a custom Trinnov processor. Despite its size and depth in extension, the upper frequency limit is still ~80Hz. Combined with the 12" & 13" JL subwoofers in the room I expect fairly impressive results.
talk about understatment! ;)!
 

FrantzM

Member Sponsor & WBF Founding Member
Apr 20, 2010
6,464
6
255
#9
Once all of the acoustic treatments are in and fabric goes up, the system is optimized using a custom Trinnov processor. Despite its size and depth in extension, the upper frequency limit is still ~80Hz. Combined with the 12" & 13" JL subwoofers in the room I expect rather impressive results. :)
A fair understatement

:D
 

Steve Williams

Site Founder, Site Owner, Administrator
#10
a design which uses many JL audio subwoofers distributed around the room per their BOSS optimization process for the subwoofers.
Mark

can you explain the BOSS optimization process. Is that from JL Audio or is that proprietary to Keith
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#12
Not big enough;)

What are the approximate dimensions/volume of the room all of those subs are going into?
This was a mid size space compared to some of the project Keith's team works on, but the room is still quite involved with construction, layout, and even a rather cool projector implementation at the back wall. I could be off on the dimensions, but I believe this was about 20' x 28' with 10'+ at the front/deepest point of the room. For some perspective, that's similar in footprint to Art Sonneborn's theater with a little more height.
 
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Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#13
Mark

can you explain the BOSS optimization process. Is that from JL Audio or is that proprietary to Keith
This is the designation Keith Yates has given to their proprietary Bass Optimization & Specification Service (BOSS). This is the process by which complex models of the listening room are created and Computational Fluid Dynamic (CFD) modeling is employed. Amir described this process in the write up of Madrona Digital's showroom. I'm not 100% on all the latest details as they continue to expand the optimization process and options, but the effective process makes for an iterative evaluation of many allowable subwoofer locations and outputs a ranking of the top configurations with a ranking of Mean Spacial Deviation (mean SPL variation across the seating area). For each ranking the process determines the polarity and relative gain of each subwoofer in the set.
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#14
As previously mentioned, the owner of this monster subwoofer and theater was generous enough to host an opening night where he invited everyone who was involved with the project as well as many friends and family. What started as a moderate size list ended up drawing more than 80 people last Friday night.

I'll have to post more later, but here are a few quick pictures of the UberSub in final dress and installed in place and the finished theater. I only had my iPhone with me, so I did what I could. I figured most would welcome any pics I could grab. :b



And myself for some scale:

Fancy badging:

The cover to conceal the beast:
 

Steve Williams

Site Founder, Site Owner, Administrator
#15
Great project Mark.

Congrats

Did Keith design the sub and you built it to spec

I saw his signature on module 2 but not yours.

BTW, I hope you're joining us for dinner again this year at RMAF. Sat Oct 13
 
Apr 3, 2010
15,814
9
0
Seattle, WA
#16
I had missed this thread before. :) Great job there.

I had chatted with Keith about having him design one of these for our showroom but we just have not had the time. Good inspiration to think of doing something like this :).
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#17
Great project Mark.

Congrats

Did Keith design the sub and you built it to spec

I saw his signature on module 2 but not yours.

BTW, I hope you're joining us for dinner again this year at RMAF. Sat Oct 13
Thank you Steve,

It certainly was a very cool project to be part of. I definitely plan to make the dinner at RMAF and this time be able to stay for the duration.

For this project, and many others I do with Keith's team, I am contracted to design a subwoofer for the application and needs. The design of the subwoofer is entirely my own, but the idea to build such a beast and the function it serves in the system was born from Keith. If the picture was larger, you would be able to read where the plate indicates me as the engineer, and Seaton Sound as the fabricator. We work together to confirm the performance function they are looking for, the space or spaces available, and what is actually possible in the time frame and budget available. The requirement for the "UberSub" function in the system was to have much greater 10-25Hz capability than the other subwoofers placed in the room to best smooth the 25-100Hz range across the seating area. This less common PR-bandpass design is my own design I've been working with for 6+ years now, and has particular advantages in reducing the most audible of distortions at very low frequencies, and enables frequency responses and efficiency which are not easy to achieve with more commonly available drivers.

The space which was available in this project was large enough to accommodate a quad driver system using 18" front PRs, but the size of the drivers and the length required for the port made it more complicated and would compromise performance if implemented as a pair of stacked boxes rather than the single monolith. In the long gestation of the project some of my parts suppliers had issues, and in testing with the level of power we now have available we found misbehavior with some parts originally planned for the design. Through lots of testing I found a set of parts with much improved capabilities over the originally planned parts, but these also were larger and much heavier. Assembling and loading such a beast, let alone the off chance of having to service it made for some sleepless nights. Through a few design iterations I eventually I came to the module assembly seen in the first post. This modular assembly approach made for easier QC and verification testing of each element, and made for a much more practical installation than a huge monolith like the your old Wilson XS. With some of the current trends, I would wager you will see more similar modular implementations by others over the next few years. Of course this is nothing new as speakers like your Wilsons have done this over a few generations, and even the Martin Logan Statement E2's, of which I installed a few sets, used a stack of 4 reasonably sized bass modules linked together into 2 towers of 8x12" woofers.
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
355
74
435
44
Chicago, IL
www.seatonsound.net
#19
Some more pictures of the room:

I took these two while Keith & Remi were doing their final testing, verifying and voicing with 8 microphones at various seating locations through the room. You can see the rear seating area and the space in the middle of the row where the quadriplegic owner can park himself front and center. There is a ramp which comes down behind the rear row of seating and around to the middle row.
Rear:

Front:


With all the lights out you can turn on strip lights which light the bottom edge of each speaker hidden in the room. The lights cycle between blue and green and make for a fun way to show what's going on behind all that fabric. The speakers are all B&W CT 800 series:




Here you can see on the left wall where there is another CT800 with 2 JL 212 subs behind.


The CT800 is a wide front speaker implemented with Trinnov's re-mapping capabilities. The JL's are part of the distributed subwoofers which smooth the bass per the BOSS optimization which uses a total of 8 subwoofer locations plus the UberSub. When I peeked at the measurements of the 8 microphone locations I saw a variation maybe +/-3-5dB between all the locations. Anyone who has actually measured a real room with seats spread over such an area knows that is a non-trival achievement. One row isn't impossible, more than one gets quite tricky.

My iPhone of course doesn't like the low light very much, but here's a quick shot of the UberSub illuminated behind the fabric panel:


 
Apr 3, 2010
15,814
9
0
Seattle, WA
#20
Cool :). We have white LEDs behind our wall fabric to highlight the speakers too. Often that has more of an effect on people than actually playing something! :D
 

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