SUBLIMATOR DUO subwoofer build

I have finally got around to accomplishing a much needed sub system upgrade. My present sub is a DefTech Supercube Reference. The Cube is a quality sub for movies and music, though one by itself can't come close to reference level in my room. I debated for quite some time and decided to go the DIY build route instead of buying another Supercube.

My rooms dimensions are 18ft x 19ft x 8ft. The room is totally sealed, no windows. It has four closets built out into the room to hide my extensive movies and music collection along with wire and cable, tools needed and an assortment of sound, light and electrical meters. It has an equipment rack between the two back wall closets. The room is symmetrical. Having measured all possible sub placement positions, I've found midpoint side wall to have the smoothest frequency response by far.

My goals for this build was performance and extension, while keeping it simple. Budget was $1000-2000. I did my research, plugged several sets of numbers into Winisd and decided on using the Dayton Audio HF15 driver in a sealed dual opposed cab, four drivers and two cabs. While I've designed and built hundreds of car audio sub cabs professionally and as a amateur home audio DIYer back in the eighties and nineties (sealed, ported, band pass, isobaric, dual opposed, etc), I haven't built any subs for over fifteen years. My first opposed driver sub build was in 1987 with 4-10" subs in a dual dual-opposed config. Very clean and tight sound. In recent years the dual opposed design has become quite popular. Enter the Sublimator Duo. Every good sub needs a name. I came up with word Sublimator years ago. It's based on the the words "sublimation" and "sublime" which both have all the appropriate meanings and innuendos which could be used to describe a subwoofers qualities and actions. Sublimator Duo is in reference to dual drivers of these subs. There's also a Sublimator Quad on the drawing board for a future date. My goals and expectations were to get 115db@20hz and 100db@10hz. I don't have the OM graphs for the DefTech(sold the sub), but the sub was flat to about 20hz. The turn is more like a cliff with no real useable output below 20hz, and when I say below 20hz, I mean 19hz. So I did my research, which was primarily reading the extensive resources provided here by the "DIY Pros", for which I'm very grateful, then plugged several sets of numbers into Winisd and decided on using the Dayton Audio HF15 driver in a sealed dual opposed cab, four drivers and two cabs. While this driver is one of the more popular units out there, my reason for picking this driver was for its low distortion capabilities and proven sound quality. Xmax and spl wasn't my first concern obviously or I would have gone elsewhere. It took two weeks to build the cabs from start to finish or to the state they are now. Once completed, I powered them with a new Behringer EP4000 (currently temporarily standing in the corner due to noisy fan and no remote trigger), and currently, with some older amps I've pulled from storage, two Parasound HCA1500a bridged providing 630 watts into a 8ohm load. Shortly after startup I had two drivers make noise and had them replaced, which took several weeks to turn around.

I've have now been enjoying the subs for a month and they sound fantastic. Quite a different sound from the Supercube. Acoustic bass, cello and kettle drums have a realism, texture and correctness that I haven't experienced before. The dynamics are exceptional. Ferocious when they need be, but soft and subtle when thats called. The sound is extremely clean and highly resolved, with huge dynamics. Having the fat ULF heft impresses me as much during low levels as it does at bombastic, bass heavy, levels. I used to constantly fiddle with my other subs, as I was never really satisfied with the sound. The smooth, extended, low distortion sound I have now, has been a real joy to listen too. Watching movies is likewise a new experience. In the past anything above -13db just lost dynamics with the limiter/roll off of the DefTech. What a difference to not be sub limited. Having usable ULF output changes everything. I now revel in the gorgeous, accurate sound, instead of critiquing everything. True to the source in every way.

The last few weeks I've spent OmniMic'ing the subs and making various comparisons and graphs. For instance, with and without Audyssey comparing frequency response at various listening positions, different crossover points, room gain, etc. Now that the subs have a few hours on them, I'll measure a few movies. As I only had my iPhone to snap pics during the build, the pics are pretty disappointing. Oh well, here goes.

Here's the room layout using iDraw for iPad.It's to scale. A square equals one inch.

Here's the Winisd file.

Here's the LP response which is from the middle of the room seat.

Here's sweeps with all speakers and the subs set at same level as mains. The +5db sweep though clean, was very loud. At this point to go higher to test the limits of the amp/sub combo I will have to raise the sub gain up 10db's or so. The mains were still going strong though. I measured room gain by comparing the Winisd graph against actual in room via the OmniMic and RG starts at +1db@20hz and increases at 10db per octave. It's +11db@10hz and +21db@5hz. Room gain is more than I expected, but I wish it started an octave higher. This is with Audyssey in which it looks like it provides a shelf filter below 20hz.

Thanks.

Yes, exactly 4.006 or so with driver and bracing accounted for. Added about 8lbs polyfill per cab. I think it's 135 if I remember correctly. I weighed the wood after final cut and router and it was 93lbs per cab for just the wood. Cabinet external is 25.5x22.5x31.75, HxWxD.

You were of course one of the above mentioned Pros which was extremely helpful and necessary for this build. Thank you very much.

Heres a larger OM graph of 5-100hz FR. Will run it up with this test to see what these subs will do. I know I'm taking a hit by not corner loading but as stated above extension and as close to flat response is what I prefer over shear SPL. I'm flat +-2db from 10-80hz and +-4db from 5- 100hz, thanks too a sealed room and a surprising amount of room gain. Shocking actually. At 5hz with the +20db gain its like going from a 100 watt to a 10000 watt amp. And that gain is before any EQing thus it's free db's.

I'm just now getting to that part of sub testing. I'm definitely mindful of over excursion at ULF but I'm only putting 300 watts to each driver. While I used to run my sub 3-5db's hot, I run the new subs flat, probably because of the extended ULF. Even with this the subs have to be set at -10.5 in the preamp to match. So even though XT is shelving the subs by 8-9db's below 20hz , I have some headroom. I played Terminator Salvation at the 38-44 min mark while I was playing around with my Omnimic the other night. I had the system set at -7 just try the subs out. I ran the same 5 mins of the movie through 3X just to make sure the drivers where ok as I had 2 drivers that had issues out of the box. The subs where pushing air. I reset the meter and each time the peak read 122.8db. I will try HTTYD and WOTW shortly and post. I also played Titan AE for a friend and that was strong.

Don't I wish. No just a 3/4" flute, straight edge and router, the old fashion way. Its the only way I can keep my box straight. Makes assembly simpler and I don't have to use a square.

Thanks. I'll see what I can find. Really disappointed with my pics. Even with editing they just didn't turn out. I'll go more in depth with the finish process I used soon.

Thanks. Wired in phase like dual drivers on same baffle. Use Winisd tha same as you would a regular dual driver cab. Same principle as bipolar speakers. One big benefit is cabinet resonances are kept to a minimum which improve performance of sub. The cabs look small to me for being 8 cuft. There a lot of these DIY builds here.

One rubbed out of box with hand check. Other one had intermittent noise, a metallic rattling noise that I finally isolated with test signals at 55 and 90hz. Both were replace by PE without issue.

Spent some time this evening running max spl tests. With 315 watts to each driver the amps were the limiting factor as I had no weird sounds coming from the drivers. The first graph when compared to my previous curve shows a gain of 4db's above 15hz, but gain drops at about 15 until at 5hz it's only up 2db's. Drivers never made any metallic noises or sounds but just stopped increasing in volume.



The next second set of graphs are with the +10db LFE ch only. For this test I ran a narrow band continuous 10-second sine wave at 10hz & 17hz. For these tests I turned up the volume until there was no more gain. The 17hz used 1/24 oct smoothing and the 10hz 1/6 oct just to experiment with it.





Tomorrow when I have time I'll start looking at various movie clips. Thanks for the compliments.

Thank You. My grandparents live in Vancouver and they are in their mid-nineties. Must be the good Canadian living. That area is still the most beautiful place I've been too in my life.

My original intent with this project was a DIY with emphasis on it being an everyone build. I normally purchase paint from an auto paint retailer and spray with my compressor. I'm more of the wood & cabinet side here than the driver & design. This time I wanted to build with minimalist of power tools and can paints instead of quarts. I even bought a cheap $40 router. That didn't work out to good and after a day of messing around to try to prove a person could build on the cheap I dumped the router and circular saw and pulled out all the heavy hardware. I spent an hour routing the baffle on the first box and 10 mins after I pulled out my real router. I did manage the finish with the cans though. Three coats of gray auto primer, three coats of black lacquer and three coats of Deft Gloss Nitro. Took way to long though with the cans. I haven't even finished the cabs yet. When their done it will be like a mirror. I like the nitro finish to dry for a month before I cut and polish. I've tried different piano black finishing methods and if you buy a good 5" sander and by a product called Micro Mesh in the 5" disc's, you cant go wrong. Amazon carries it.