Anyone looked at the JL Audio W7's for home subs - diyAudio
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Old 9th February 2007, 02:15 PM   #1
pjpoes is offline pjpoes  United States
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Default Anyone looked at the JL Audio W7's for home subs

Hey guys, I currently am using a Parts Express Dayton 12" refrence series HF subwoofer in a sealed box. I am having a 4.5 cubic foot box tuned to 21.5hz made for me, as I mentioned in an earlier thread, which I will move that woofer to, and power with a 500 watt amp. This models an output of around 110-112 decibles peak from around 21hz-crossover point. I obviously don't know inroom specs yet, but predict some lumpiness to be added, and some room gain. In the 2 cubic foot box I modeled max output to be the same as the ported box, but rolling off at around 3 db's per octave starting around 50-60hz or so. It's -10db point is around 20-22hz or so. In room I actually measured it to be about the same as modeled, a little better, but not what I was hoping to get from room gain. Hence why I am trying a ported box now.

Always on the lookout for a way to upgrade my projects in the future, I started modeling other woofers in the same box, to see if any would be a good drop in replacement. One stood out as not only a good drop in replacement in that box, but a good home subwoofer driver period. I modeled it against just about everything I could find, and price/performance ratio really puts it up there. I know its still a pricey driver, but in the 4.5 cubic foot box tuned at 21.5hz I get a very flat response down to 20hz and max output of around 117-118 decibles with around 1500 watts. Also, at 1500 watts, it still doesn't hit xmax, however with 2000 it does, but the extra headroom might buy you a few decibles in the 40-60hz range and 20-25hz range.

Just to see, I compared this single 12" driver to other similar subs, like the brahma, and couldn't get the same output. I also tried pairs of 12" and even 15" subs for comparison and what I found was that it generally required a much larger box in order to achieve the same performance, and was difficult to beat the performance without spending considerably more. For anyone who wants to spend say between 700 and 1000 dollars, I highly recomend building a home sub using this driver in a ported box with 1000-1500 watt amp. Beyond 1000 is going to require a proamp and crossover probably, but I'm sure its worth the extra complexity. You could also probably do this project for much less money if you bought a used woofer or got a deal on it, had the amp around, or got a deal on it, and made the box yourself.

Just for some more ideas, I modeled the Image Dynamcis IDmax, also looks great for a home sub, doesn't model quite as well in the 4.5 cubic foot box, but does give a sort of shelf response, only being a few decibles down at 20hz. It gave similar performance to the JL, better than the Brahma, and all at the cheapest price overall. I would add too that I have used both the IDmax and W7 woofers in car installations before, and they are very linear woofers with very low distortion. I have always been impressed by them, just found them too expensive.
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Old 9th February 2007, 02:25 PM   #2
pjpoes is offline pjpoes  United States
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OH I want to add before I get flamed for not finding the one or two better value woofers, the Stryke Audio woofers modeled great too, always were great woofers capable of serious clean output, but I believe are no longer available.

The HE15 from Stryke in a 4.5 cube box tuned to 21hz or so gives a -3d shelf response, but with similar output to the JL at around 117db's. Handles similar power without exceeding xmax, though its rated for much less, cost considerbly less money, and was more effecient to booth. Two of them in ported boxes with around 3000 watts of power will give around 125 decibles output, as will the W7.

Man sounds funny saying 3000 watts, just a few years ago that would be like saying 1.3 gigawatts, just an obsurd number that nobody could reasonbly afford, now-a-days you can pick up many a pro amp that will put out that kind of power no problem.
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Old 20th May 2010, 05:15 AM   #3
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Find a local dealer and listen to JL Audio's own Fathom series home subwoofers. It could give you a pretty good idea of the performance you can expect.
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Old 20th May 2010, 07:21 PM   #4
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Hmm, a 4.5 ft^3 tuned to 21.5 Hz requires a TL size vent to handle a high Xmax 12" at high power (> 6" dia. in area), so if you're not using PRs, then figure you'll lose up to 6 dB down low in vent compression plus VC heating could rise enough to make it audibly under-damped even without any room gain, potentially making it a boom-box in-room on some recordings.

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Old 21st May 2010, 01:07 AM   #5
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by GM View Post
Hmm, a 4.5 ft^3 tuned to 21.5 Hz requires a TL size vent to handle a high Xmax 12" at high power (> 6" dia. in area), so if you're not using PRs, then figure you'll lose up to 6 dB down low in vent compression plus VC heating could rise enough to make it audibly under-damped even without any room gain, potentially making it a boom-box in-room on some recordings.

GM
Agree with Greg, See the simulation of a JLAudio12W7-3 in an aperiodic ported 5.33 cu.ft box where the port diameter is 6" at a 1 Hz x-max safe SPL.

The excursion is almost hitting the maximum recommended limit, even with a stuffed port.

As usual I prefer a T-TQWT solution where the box volume is brought down to about 3.32 cu.ft and no aperiodic behavior is needed to tame this driver.

b
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Old 24th May 2010, 05:08 PM   #6
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Overpriced and over-hyped. A great driver, but unless you can get one on the cheap used I'd look elsewhere.

Folks in the car audio scene are having very good resultsm (and I mean significant improvement) with fluted ports with high excursion woofers and that might solve some of your turbulence or compression issues if you are worried.
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Old 26th May 2010, 02:19 AM   #7
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Originally Posted by hispls View Post
Overpriced and over-hyped. A great driver, but unless you can get one on the cheap used I'd look elsewhere.
So what other driver has such a huge x-max and willl work in a small sealed box and handle the watts needed to have decent output?

I sold 8 JBL 18's (in isobaric cabinets that were still way too big). But looking at some of the newer smaller drivers I am amazed at the huge x-max. I've obviously been away from this for too long, and don't know what's available. What's obvioulsy available is all the amplifier power you can use. It looks like the 13W7 can make for some really powerful small subs that really go low. What else should I be looking at (for small sealed cabinets, size is critical, want to go really low, behavour below fs is important, efficiency is not important at all, power handling is important.
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Old 26th May 2010, 04:12 AM   #8
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Listen to the 12W7 HO box that JL Audio makes. That should give you an idea of how good the sub can sound in a vented box. There is a lot of criticism of the JL 12W7 based on price, but not performance. The 13W7 would have been my second choice, but I decided to go with a Maelstrom-X.

Depending on how far along the box is, consider the following. (Please keep in mind I don't have box modelling software on this computer.) Slot ports will be better with this sub and will reduce the air velocity and the other bad things described above. The slot port will change the internal size of the box considerably, so you will have to do some iterative calculations to figure out the best combination of box internal volume and port dimensions. Also, for the 12W7 you should double the front baffle, placing the second 3/4" MDF baffle on the inside. It should also be heavily internally braced. Both these will reduce the internal volume further (figure out how much before trying to find port and internal volume), which will get you closer to the ideal box size for the 12W7.

Or, do like me and have a sealed 18" Maelstrom-X in 4.3 cu ft that, after REW and BFD, is flat to 20 Hz...
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Old 26th May 2010, 01:45 PM   #9
hispls is offline hispls  United States
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Originally Posted by cyclecamper View Post
So what other driver has such a huge x-max and willl work in a small sealed box and handle the watts needed to have decent output?

I sold 8 JBL 18's (in isobaric cabinets that were still way too big). But looking at some of the newer smaller drivers I am amazed at the huge x-max. I've obviously been away from this for too long, and don't know what's available. What's obvioulsy available is all the amplifier power you can use. It looks like the 13W7 can make for some really powerful small subs that really go low. What else should I be looking at (for small sealed cabinets, size is critical, want to go really low, behavour below fs is important, efficiency is not important at all, power handling is important.
I have some 12" TC-4000 LMS drivers that have insane x-max, hold 1000W very well, and beat my old 15" TC-2000's in the 20-25hz neighborhood in about 3 cube ported at 27hz. The downside is the LMS coils (and most of the other linear tech) is somewhat inefficient and 3KW peaks will make them smell funny within a few seconds. Really I'm a big fan of their larger drivers since the 10" soft suspension, large and deep motors, and tall rubber surround really allow for effortless ultra low material.

In addition to the TC/Audiopulse, Soundsplinter RL-s is very similar to the 4000 LMS and IIRC is more geared for sealed applications (though I'd highly reccomend port/passive radiator if you want to do <35hz well particularly in a small box).

The Exodus audio lineup (Maelstrom, etc.)is also very nice with the XBL^2 tech. I bought some small woofers from them last year and they are very well built, great value, and the company was fast and friendly.

Honestly for the price of W7 you'd really expect some sort of linear motor technology??? Also they're not terribly clear on how linear the motor is at or around their advertized 32mm x-max. I know the XBL^2 and LMS designs maintain about 80% of BL at their "rated" x-max. I promise you will notice the difference in these newer motor topologies if you plan on really stretching things to the 2" peak to peak mark

That all being said, the W7 is a great sounding driver every time I've heard one and if you can buy one at the right price you can always play with it and re-sell it at not too much of a loss if you decide to mix it up. For the price of a new one I'd look elsewhere.
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Old 26th May 2010, 02:15 PM   #10
Glowbug is offline Glowbug  United States
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Honestly for the price of W7 you'd really expect some sort of linear motor technology???
Compare the W7's BL linearity next to something like an older style RE XXX, fairly standard XBL^2 design. I don't think you'll be too disappointed
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