OJ's Dual UXL-18 Sealed Build

[OJ Bartley]

Well it looks like some content is needed in this section, and I'm proud to be the one to open it up. This will be a truncated version of my sub build, with more detail coming as it evolves.

I am currently getting closer to finishing a pair of sealed UXL-18s, which I'm thrilled to have. In my opinion, they are among the top 3 HT 18" sub drivers, and are truly a high end product. I'm looking forward to putting their 34mm of Xmax to use in destroying my house. The enclosures are just under 3.5 cubic feet after accounting for driver and bracing. They will be powered by a single nu6000 (non-DSP model) and tweaked by a MiniDSP.

Attached are a few pics of the build process up to now. If anyone has questions, please don't hesitate to ask.

 

[Tonto]

Hooked...love sub builds!

 

[Prof.]

It's coming along nicely Owen

 

[chrapladm]

Looks very nice. Hopefully I will be able to make some saw dust soon also on my projects to add to this section.

 

[Sonnie Parker]

A big THANK YOU Owen for kicking this off for us... you are so right, we need this.

Looking forward to following your build project.

 

[tesseract]

Alright, Owen, thanks for kicking off a great post in our DIY Subwoofer subforum!

I have an IXL 18 2.2 sitting around here to build out. Mach 5 drivers are indeed high end and will rock the house, no doubt.

 

[OJ Bartley]

Thanks guys! Glad I can contribute. It also gives me some incentive to get cracking on the project.

Speaking of which... Progress continues! Small steps, but it's all I could manage with some sick little guys at home this weekend. One coat of primer on to seal. I need to do some sanding in a few places, and might do a second coat of primer, but I'll probably just go on to 2 coats of paint. Next update should be all painted, with terminals mounted. Maybe even drivers. Anyone have a go-to material for securing and making the terminals airtight? I'd use PL, but I don't want to open a tube just to deal with 4 little terminals. Needs to bond well to MDF and plastic.

Dennis... that IXL must have been sitting there quite a while! I don't even remember when they were in stock last. Any specific plans for it?

 

[Todd Anderson]

Owen, looking forward to seeing this take shape! Thanks for brining it here!

 

[Prof.]

I think just the small 2 pack instant Araldite would do the job of making them airtight..

 

[Jororaitchev]

Hello,
I have a few questions if you allow me:
- what are you going to "feed" these "monsters"?
- if possible a picture of other speakers /regardless that is the posts for subs /,i am interested in why you had to make two subs?
- do you have in your house special room for "Home cinema", i mean acoustically processed?
Thank you,
Joro
P.S.
I think there is a need for more processing in the interior of the cabinet, the corners should be rounded.

 

[OJ Bartley]

Owen, looking forward to seeing this take shape! Thanks for brining it here!

My pleasure, Todd. I hope it doesn't take forever to actually finish.

I think just the small 2 pack instant Araldite would do the job of making them airtight..

Thanks Prof. I was going to make fun of you for recommending some obscure Aussie product, but it turns out it's readily available here at WalMart, and I'm just an uninformed schmuck. Although, I do have some comparable 2-part JB Weld epoxy, so that's probably what I'll use. That will make them rather... permanent.

Hello,
I have a few questions if you allow me:
- what are you going to "feed" these "monsters"?
- if possible a picture of other speakers /regardless that is the posts for subs /,i am interested in why you had to make two subs?
- do you have in your house special room for "Home cinema", i mean acoustically processed?
Thank you,
Joro
P.S.
I think there is a need for more processing in the interior of the cabinet, the corners should be rounded.

Joro, thanks for the interest! Your projects are very impressive, and turn out beautifully. I'm sorry, my initial post lacks a lot of the usual detail because I was pretty far downstream with this project when I started the thread.

I'll be using a single iNuke 6000 (non-dsp) in stereo for both subs, which should provide around 1,200w each, using a dedicated 20A outlet. If I remember correctly, it should be capable of peaks somewhere around 1,600w I think. Being in sealed enclosures, I shouldn't have to worry about overexcursion, and I will have some headroom to tweak (increase) the response in the very low end with a miniDSP. I will be using the "balanced 2x4" version, and I'll include details here on what I do regarding cables, since they use bare wire connections to the unit.

These subs will be part of our dedicated theatre build. We have an unfinished basement that we are hoping to finish all at once in the near future. The plan is for a dedicated room at one end, which will be about 9' wide by 19' deep. I'm aiming to use a false wall at the front with an acoustically transparent screen in a 2.4:1 ratio. The main 3 speakers will be these recently completed DIY Sound Group HTM-12s.



The 4 surround (back and side) and 4 Atmos speakers will be DIYSG Volt-6 speakers built into the walls and ceiling. I'll start on these after we get framing finished in the room. I decided to build 2 subs because I wanted to make sure I would have "enough" output in this dedicated room (I know, I know, it is never enough!) and I want it to be impressive when we put on a big action movie. I'm currently using a single ported 15 and a single ported 10, and these would seem to be a good step up. Also, having 2 subs gives me some options when it comes to placement. I decided not to round over the internal bracing because I think the general consensus is that it isn't required for subs. I did it in my previous builds, but left that detail out of this one. Each sub will have a pillow or two stuffed in it when completed.

The room itself will have some degree of soundproofing (probably double drywall with green glue) as well as interior acoustic treatment with an assortment of absorption and diffusion panels. I'm not going to go all-out, but I do want to at least plan for some degree of isolation to help keep movie sounds IN and other sounds OUT. I'll definitely start a thread for the theatre when we get around to starting. Right now we're still cleaning out the basement, so hopefully we can start sometime in 2017. I'll try to post a thread on the HTMs as well.

 

[Jororaitchev]

Thanks for the reply!
I am very glad when a large DIY project is being carried out. I will help with whatever I can. Success!
Joro

 

[chrapladm]

No need for rounded corners in the inside of a subwoofer. When dealing with subwoofer frequencies the sign waves are larger than the cabinet. SO no need to unless just for looks of OCD. The outside/room is where all the processing needs to be done.

 

[Jororaitchev]

No need for rounded corners in the inside of a subwoofer. When dealing with subwoofer frequencies the sign waves are larger than the cabinet. SO no need to unless just for looks of OCD. The outside/room is where all the processing needs to be done.

Yes, I know what is the length of the sound wave at 20 Hz, but I also know what is the ideal shape for a speaker body - I hate making angles in the structures of the sound cabinets.Sorry, if I try to impose my opinion!
Joro

 

[tesseract]

Dennis... that IXL must have been sitting there quite a while! I don't even remember when they were in stock last. Any specific plans for it?

I have a 17 Hz tune slot vent plan that the late DIY'er, Mike Paulson, created.

 

[OJ Bartley]

I have a 17 Hz tune slot vent plan that the late DIY'er, Mike Paulson, created.

17Hz should be a great tune for the IXL. And look, you have a brand new DIY sub forum to document your build in... that's convenient!

 

[tesseract]

17Hz should be a great tune for the IXL. And look, you have a brand new DIY sub forum to document your build in... that's convenient!

Owen, it is DIY'ers like yourself that this subforum was created for.

 

[OJ Bartley]

Yes, I know what is the length of the sound wave at 20 Hz, but I also know what is the ideal shape for a speaker body - I hate making angles in the structures of the sound cabinets.Sorry, if I try to impose my opinion!
Joro

Joro, sorry I missed this post! Ideally, yes, I would have liked to include some non-parallel walls or panels, but things are tight in there, so I'm just going to hope my bracing is adequate to keep resonance down, and rely on stuffing to minimize the effects of internal backwaves.

 

[OJ Bartley]

A quick pre-update that I thought I had already posted. I decided I definitely wanted to have options for where to plug the speakon connectors in, and options for how to orient the sub in place (facing out, facing back, sideways, whatever). To make this a little more feasible, I decided to install a pair of jacks on each sub. It was a relatively simple job to wire up the internal connection, and shouldn't have any downside, so I'm glad I did it this way.

 

[OJ Bartley]

...And we have arrived at the final chapter at last. Over the weekend I wanted to make a push to complete these subs, because enough is enough. Projects can drag on, but I really needed to get this one wrapped up. To force myself to get things done, I brought the driver and enclosure in and parked them on the dining room table. Please ignore the circus sideshow that our house has become with 2 boys and all their toys and no basement yet. Sorry, some of these pics are pretty bad, apparently my phone doesn't do well in low light.





My strategy worked pretty well, and I got the sub put together at naptime on Saturday. I forgot to weigh the completed enclosure with the driver in it, but I'm definitely glad I didn't have to move it very far. The screws I picked worked really well. I just lifted up the edge of the gasket, placed the screw and sunk it, and when the gasket goes back into place it's virtually invisible. The integrated washer gives me some more confidence about its holding ability.



So, fully assembled and upright, I'm pretty happy with the final product, although I do still wish I hadn't messed up my initial design plan for the chamfers. The Neutrik jacks flush mounted pretty nicely, and I'm glad I'll have some flexibility regarding plug placement because those things really do stick out when connected.





Here's the first completed sub next to the SDX-10 it will be temporarily replacing. The enclosure really isn't THAT much bigger on the whole. The SDX is still a great little sub, and will probably come back to living room duty when the basement gets finished.





And set up in place (for now) it really doesn't look that big, especially compared to the Tempest that's twice its size on the other side. I'm going to stack the pair of them for now, and probably still run the Tempest too, unless it really messes things up.





I didn't get to do a lot of testing, but I played around a bit with Bass I Love you, which sounded good, and Curtain Shaker, which to be honest I saw a lot of cone movement but didn't hear much. I threw in some kid friendly demo material with the Titan A.E. Ice Field scene, and was able to do a little bit of playing with the sub level and iNuke knob. I ended up with the level about 6 or 8dB hot, and still have the iNuke gain at about 2:00, which gave me the best balance between audible hum and strong output.

Now, I'm splitting the single LFE output from the Denon 3 ways (one to the iNuke, one to the Tempest, and one to the Buttkicker amp) so I assume this results in some reduction of signal strength. I haven't re-run Audyssey or changed anything other than the sub level. I know I have a lot left on the table, between doing some gain matching, adding the MiniDSP, and taking some measurements and adding filters. I really don't have an impression of it yet, I just haven't spent enough time with it.

In the limited time I've had, I like it so far. The output is there, although it seems like I have to drive it pretty hard to achieve it. It seems to be quite articulate, and blends well when it isn't pumping out explosions. We managed to find ehough time for a movie last night and put in Jack Reacher 2. It's an action movie, but not one I'd say with a great deal of low end material. It did have a few moments, which the sub handled well, but it also did a very good job of not calling attention to itself while filling in the more subtle stuff. More testing is definitely required, and when I have the pair up and running, I'll tackle the MiniDSP for better integration. I'm very much looking forward to that, especially to see if I can bring down the gain on the iNuke and reduce the hum that comes in strong after about 2:00 on the dial.

Oh, and speaking of the iNuke, I was expecting much worse fan noise. I have a recent model and although it was noticeable, it wasn't as obnoxious as I anticipated. In the final install I'll work out some kind of hushbox of sorts to cut that down, but it will be fine in the short run.

 

[Prof.]

Haha..You wouldn't believe it!..Of all the screws in the world, I used the exact same one's to mount my sub driver!!..They worked well..

 

[tesseract]

Nice job, Owen, thanks for the update. Looking forward to reading about the final integration. DIY subs are fun and blending is a challenge, a worthy one.

 

[OJ Bartley]

View attachment 2114

Haha..You wouldn't believe it!..Of all the screws in the world, I used the exact same one's to mount my sub driver!!..They worked well..

I'm not surprised at all, prof... great minds really DO think alike!!

 

[Sonnie Parker]

Those look like GRK RSS structural screws... I use them all the time.

Super impressive work Owen.

 

[OJ Bartley]

Yep, @Sonnie for the win with GRK. I had a reference to them in my older "extended" thread but I guess it didn't make the redux version. I was very happy with these. Hopefully they'll hold nice and strong for a long time.