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Discussion Starter #1
I was recently able to just squeak in to a group buy for a pair of Mach 5 UXL 18s, and I jumped on it before I had a chance to do much research or planning. I took enough time to assure myself that the price was right, and that they were still solid performers, and the local Canadian source (no need to re-ship/drive to border/etc.) was what sealed the deal for me.

I had been planning for a long time to use a pair of sealed 18s in our theatre build, so there’s no deviation there. I was considering the SI HT18 before they disappeared, and then looking at either the new DS4-18 or possibly an Ultimax 18, both a step up with a corresponding increase in price. When I saw the chance for a pair of UXLs, I did some quick googling and determined that they seem to have more output capability than the other 2 (at least a higher Vd), were well regarded, and perform well in small sealed enclosures. That’s another plus for me, because I wanted to keep mine under 2x2x2 to hide behind a tight screen wall. Price will be reasonably comparable by the time I get them all to my door, though they are still likely a little more than the SI or Daytons would have been.

Now... what to do with them!? As I said, I had been planning for a pair of sealed 18s. Right now I’m running a large ported (original) Tempest tuned to 19Hz, and a ported SDX10 tuned around 25Hz. By my calculations, those two combined still fall well short of the Vd of a single UXL, so I think I’ll be in for a noticeable upgrade. I’ve been very interested in trying a Linkwitz Transform design for a long time, and I think that’s the route I’d like to take with these. I like the idea of a small sealed sub with a very capable driver given a good amount of power and EQ to achieve optimal results. My planned amp so far is an inuke 6000DSP based on the performance per dollar ratio. I get the impression that the UXL is a hungry beast, and I want to make sure they have enough power to really get moving. With that said, my room is less than 10x20x8 (1,600 cubic feet) so I don’t anticipate the need to drive them very hard to get enough output.

So, where do I start? It seems that the UXL likes small sealed enclosures, so let’s start with about 3.5 cubes, which seems common. A 20x20x22 enclosure made from 3/4" material with a double front baffle, less about 1/3 cu ft for the driver gives me 3.566 cubes (internal). Minimal bracing won’t hurt that too much, and stuffing will help to offset.

If I’m modeling that correctly in WinISD, that gives me an f3 of 46Hz, and an f6 of 32 Hz. Now I’ll need to improve on that. If I wanted to do it quick and simple, I could use the DSP from the inuke6000 and dial in a few bumps. Alternatively, I still have my BFD (Behringer DSP1124P) that I could use for simple EQ and not need the DSP model inuke. OR... if it actually provides a better solution, I’d be happy to skip the DSP model and pick up a MiniDSP, which I could program with the Linkwitz Transform tool and do it properly. I have a few problems here.

First, I don’t really have a specific target frequency, I just want to maximize my useable low end response. Second, I’ve been playing with the LT in WinISD and it seems to take the cone excursion beyond Xmax pretty quickly with well under the 3,000W theoretically on tap (as expected, really). Building in a 10Hz high pass seems to help, but I really don’t know how to properly model this and integrate real world amplifier power.

I guess that’s where I am right now. Maybe not as completely lost as I thought, but in need of some serious mentoring to make what will be my last (?) sub build as epic as it can be.
 

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Discussion Starter #2
Continuing with my fumbling in WinISD... I like the idea of designing everything, including the LT in WinISD, because it lets me see the effects of my EQ, rather than just adding +6dB of boost at 20Hz after I get it in-room and wondering why it went CLANK. I know I'll still need some tweaking after setup, but my plan is to maximize low extension within safe Xmax limits, and then if I have to EQ in-room I can stick to making cuts to flatten my response.

Here are 2 graphs from my experimenting. Sealed enclosure (3.566 ft^3), Single UXL-18, using 1,200W input power. Yellow is the original model, and blue adds the LT filter specified. At this point the LT was just a result of playing with numbers, there was no hard reason behind what I used.

Clearly I need to work on the excursion in the LT model, and I'll try out a high pass at 10Hz or so, but is this generally how people manage the details? Just trial and error? I’ve been told that many Behringer users apply a voltage limiter, and I need to do more reading about them.
 

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I'm no expert in LT sealed subwoofer but I do know that usually you should need less boost in real life versus WinISD because you should get some room gain in real life. Also even if your room is pretty large you should get some room gain down low so that will help reduce the amount of boost required.

Don't forget too that most electronic have a rolloff down low. I beleive the iNuke is down 2-3db at 10hz (basically 50% less power) so that can etheir serve as a soft high pass filter or require more boost to overcome the rolloff.

Other people will shime in but I think that the correct approch would be to measure your output in room after building the subwoofer and then etablish what kind of LT is required. Then if you want you could add it into the WinISD simulation to see how much excursion you are using.

The iNuke 6000 should deliver 90~94 volt (2000-2200 watt) of real watt at 4 ohm with 1 channel driven. If you drive both channel this hard at same time it will go reset. It can deliver about 1750-1800 watt into 4 ohm both channel driven.

By the way I'm looking forward to your build. I'm Canadian too and currently looking to upgrade my speaker for SEOS fusion speaker. Then the next upgrade will be subwoofer duty because the new speaker will dwarf my Trio12 subwoofer. Unless I change my mind again I'm looking at 2 UXL-18 ou 2 FTW-21 sealed. There is just something about very large driver that attract us...
 

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Discussion Starter #4
The iNuke 6000 should deliver 90~94 volt (2000-2200 watt) of real watt at 4 ohm with 1 channel driven. If you drive both channel this hard at same time it will go reset. It can deliver about 1750-1800 watt into 4 ohm both channel driven.
Thanks for all that Steeve-o, much appreciated. I've read similar to the part I quoted, and possibly that those are peak numbers and RMS would be closer to 1200w both channels driven (4 ohm) which seems just about right.

I think you're right, and the best way to approach this might be to build it, measure in room, and then see what I need for EQ. I'm a little over excited about this project, so I wanted to get something going right away. :)

I'll see what I can come up with for an amp, and start looking for a minidsp.

Oh, and I'm planning on SEOS mains as well! If I can fit them, I want three 88 Specials behind my screen. I'll have to keep an eye on your projects too. Which model are you building?
 

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I beleive the 1200 watt spec for the iNuke is 100% duty like sinewave. The 1800-2200 watt spec is 1/3 duty which is supposed to be heavy music program. I think that for movie you should get close to that especially since the big bass hit only last for so long.

Currently I'm planning on Fusion 15 v2 for LCR and Volt 10LX for the 2 or 4 surround. I have the money ready but I'm figuring out the shipping forwarder stuff. I might go with ReShip but I'm not sure yet. Either way it will be about 250-325$ US to ship all that to Canada + brokerage and duty afterward.

I'm not set on 2 or 4 surround because I speak french mostly and movie are only translated in Dolby 5.1 (not HD) 99% of the time so the two extra are sort of not worth it. I would love to be able to watch movie in english for the true audio but currently I do not speak it enough often so that I can understand it freely without thinking about it... I have to concentrate and part of the fun while watching a good action movie is just relaxing and enjoying.

If you want to read more about the iNuke 6000 this bench test is interesting. http://forum.speakerplans.com/behringer-inuke-nu6000-vs-kam-kxd7200-bench-tested_topic69202.html
 

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Discussion Starter #6
I beleive the 1200 watt spec for the iNuke is 100% duty like sinewave. The 1800-2200 watt spec is 1/3 duty which is supposed to be heavy music program. I think that for movie you should get close to that especially since the big bass hit only last for so long.
OK, thank you, that's great to know. I'm considering power requirements in another thread (which goes hand in hand with output) and I'm now debating between a dedicated 20A or 30A line to be able to actually produce the power the amp is capable of (for short bursts)

Currently I'm planning on Fusion 15 v2 for LCR and Volt 10LX for the 2 or 4 surround. I have the money ready but I'm figuring out the shipping forwarder stuff. I might go with ReShip but I'm not sure yet. Either way it will be about 250-325$ US to ship all that to Canada + brokerage and duty afterward.

I'm not set on 2 or 4 surround because I speak french mostly and movie are only translated in Dolby 5.1 (not HD) 99% of the time so the two extra are sort of not worth it. I would love to be able to watch movie in english for the true audio but currently I do not speak it enough often so that I can understand it freely without thinking about it... I have to concentrate and part of the fun while watching a good action movie is just relaxing and enjoying.

If you want to read more about the iNuke 6000 this bench test is interesting. http://forum.speakerplans.com/behringer-inuke-nu6000-vs-kam-kxd7200-bench-tested_topic69202.html
The Fusion 15s look AMAZING. I had modeled mockups of most of the fusion line in sketchup to see what the size would be like in my room and unfortunately the 15s are a little too big to be comfortable. I started out thinking I'd go with the Fusion 6, and then basically considered every model in the Fusion and Cinema lines. I like that the 88 Special uses the big 15" waveguide that the Fusion 15 also has, but it comes in a smaller package.

Thanks for the link, I have actually been reading through that thread. Some very good stuff to know.
 

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Owen wrote:

I'm now debating between a dedicated 20A or 30A line to be able to actually produce the power the amp is capable of
Is it rated for 30A? I think it would be better to stay with a 20A circuit & increase the gauge of the wire. You could send Talley a PM & he will know for sure.
 

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Discussion Starter #8
Owen wrote:

Is it rated for 30A? I think it would be better to stay with a 20A circuit & increase the gauge of the wire. You could send Talley a PM & he will know for sure.
Thanks Tonto, that's one of the things I need to look into. I think 20A is probably the most likely scenario I'll take. But it's good to explore all the options and learn some more.
 

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Discussion Starter #9
Having read around and seen that people are successfully running multiple amps and other equipment off a single 15A circuit, I think I'm going to go for a dedicated 20A for the subs, and a dedicated 15A for the rest of the system. That should give me plenty of room if I need to turn things up once in a while.

Now to settle in for the long wait for production, and spend my time planning cabinets and other projects. I'll update as progress happens.
 

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Discussion Starter #10
Subs are now in production, and I don't even have MDF in the house yet. These enclosures will be my summer project, but they're gonna move slowly with a 3 year old and a 6 month old around. The big guy likes to help on "projects", but that's not exactly a boon for my productivity. Lol

I'm getting pretty excited for these, so hopefully in the next little while I'll finalize a design (pretty much settled I think) and put together a cut list so I can get out and pick up materials. Then I'll make some dust!! :grin2:
 

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Discussion Starter #12
I'm still playing with enclosure designs, even though they'll be pretty simple sealed boxes, but I have a few little tweaks in mind for mine. To keep myself entertained while the subs are built, I have a question.

It's just academic at this point, and won't influence my project going forward, but I noticed that the stated Sd for the UXL-18 is 1029 cm^2 (or 1170cm^2 measured by Data-Bass), and for the SI DS4 18 it's 1218 cm^2. That's a fairly large difference for 2 comparable 18" drivers. Is it just a difference in method of calculation? Do some measure using the full surround, and some using only the cone? I thought I read somewhere that the standard was to use a certain amount of the surround included in the measurement, but I can't remember.
 
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