JBL W15GTI MKII Sub - Need Recommendation Please!!! - AVS Forum
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post #1 of 19 Old 05-21-2012, 09:32 PM - Thread Starter
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Hi All,

I currently have two JBL W15GTI subs sitting collecting dust (I just never got around to building anything for them). As oppose to just selling them, I thought it maybe worthwhile to drop them in one of the DIY Sound Group enclosures. I understand none are available at the moment but they are currently taking pre-orders.

Not sure whether any of the enclosures they sell are suited for the JBL W15GTI MKII - but any input from fellow forum members would be much appreciated.

As I understand, they have the potential to perform well in small sealed enclosure.

My currently home theater setup includes two TC-2000 in separate sonosub enclosures tuned to 13hz powered by a QSC PLX-3402.

If it is worthwhile to purchase two 3 cu.ft. or two 4 cu.ft enclosure - I would certainly buy (they are just so cheap). Otherwise - I may just end up selling the subs

Last but not least - the initial idea was to use them in a HT setup. But if you all feel that I can drop them in the aforementioned enclosures and use the subs for my 2-channel music room - I will also consider that. I guess I am just desperate to put those subs to use (but just not desperate enough to build enclosures from scratch - call me lazy )
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post #2 of 19 Old 05-21-2012, 09:39 PM
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Yup. They will work in a 3-4cuft box, easily. If you are waiting for Erich's cabs, they will do nicely. Otherwise just make your own.

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post #3 of 19 Old 05-21-2012, 10:34 PM
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don't sell those drivers, they are very good.

8 cubic feet and 500 watts per driver tuned to 16hz will amp up your bass much more so than small sealed enclosures.

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post #4 of 19 Old 05-22-2012, 08:36 AM
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sell them to me.
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post #5 of 19 Old 05-22-2012, 09:06 AM - Thread Starter
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Thanks for the responses guys.

Knowing how lazy I am, I know it is highly unlikely that I will start a scratch build for them. It just wont happen

Datraz: If I can't make use of them using Erich's cabinets, then I may have to consider selling them.

LTD02: I'm sure 8 cubic feet would be awesome - but again, a build from scratch is just highly unlikely. I understand that the 3 or 4 cubic feet (sealed) could not match the 8 cubic feet ported, but do you think they have the potential to still perform well in the 3 or 4 cubic feet enclosures? I remember reading somewhere that, given their tremendous power handling, one might be able to get away with a little low-end EQ.

Scott: Thanks...that is what I was hoping to hear . Do you have any recommendation which one I should be using between the 3 cubic feet or the 4 cubic feet.

All in all - I really want to make use of these drivers. One is brand and the other one is hardly used. If I can get away with using Erich's cabinets, then I will jump on that opportunity. If the conses is that they will not perform well in those cabinets, then I may just have to consider unloading them
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post #6 of 19 Old 05-22-2012, 09:32 AM
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You know, I entirely understand:

Quote:


Knowing how lazy I am, I know it is highly unlikely that I will start a scratch build for them. It just wont happen

But those motors are quite well sorted out, and there are very simple ways to approach a diy build. A local cabinet shop, perhaps a local Home Depot or Lowes, could all easily cut your panels for you or whatever. Pickup a big powerful pro amp (perhaps with on-board dsp for EQ'ing) and you're in possession of a superb subwoofer.

Good luck

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post #7 of 19 Old 05-22-2012, 11:47 AM - Thread Starter
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Quote:
Originally Posted by FOH View Post

Pickup a big powerful pro amp (perhaps with on-board dsp for EQ'ing) and you're in possession of a superb subwoofer.

Good luck

FOH,

I do not have a pro-amp with a build in EQ, but I do have the Behringer DCX2496. In regards to the amps on had, I currently have a QSC PLX-3402 (which I plan to continue using with my TC-2000s) and also have Behringer EP2500.

Truth be told - my only two options are: a) to sell the drivers, or b) to use them in one of Erich's enclosure.

I did a quick "WinISD Online" analysis of the driver and based on their online calculator, the "optimum" sealed enclosure would be approximately 113 liters (or 4 cubic feet) - based on that, -3db would be at 40hz and -6db would be at 30hz.

I was hoping maybe I can drop them in 4 cubic feet enclosure, give them a 6db boost at 30hz, and power them with an EP2500 at 3ohm load (so approximately 700 watts per drivers)?


Any other thoughts?
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post #8 of 19 Old 05-22-2012, 03:47 PM
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That would work really well - 4 cu ft with DCX and EP2500. Friend has the same set up except with yammie amp. They are great drivers! Go for it!

explore the music
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post #9 of 19 Old 05-22-2012, 06:58 PM
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Efalegalo, depending on your room gain, you might not have to boost too much down low. A 3-4cf box per sub and your amp power will be good for the GTI's. You can even cross them over to the TC Sound subs around 40-50hz. Let the TC subs do the low bass and the GTI's do the mid-bass, which is something the JBL's excel at.

I have three of the GTI MKI 15" subs in small 2.4cf boxes w/800W per sub, fully stuffed. I've had them now for a few weeks and their performance for both HT/Music is simply great. I can say that the bass is deep/loud/clean. I know, I need to start a thread on them.
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post #10 of 19 Old 05-22-2012, 07:21 PM
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They sound horrible, very very bad, I have 2 of them. You don't want them. Sell them. I know someone who wants them badly hint hint.
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post #11 of 19 Old 05-24-2012, 12:06 PM - Thread Starter
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Quote:
Originally Posted by datranz View Post

They sound horrible, very very bad, I have 2 of them. You don't want them. Sell them. I know someone who wants them badly hint hint.


Datranz,

I see you have the MKI version. I must admit I am jealous. The one thing that really bugs me about JBL MKII version is the silver dust cap. Although I have not decided the the kind of enclosures my subs would eventually end up in, I do know they will definitely have grill covers.

Spanish68 - I might do just that --> Cross the JBL W15 to the TC-2000 @ 40hz. Can you please post pictures of your system when you get a chance?
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post #12 of 19 Old 05-24-2012, 12:44 PM
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Quote:
Originally Posted by Efalegalo View Post

,I see you have the MKI version. I must admit I am jealous.

FWIW, a lot of early Mk. I drivers had issues with tinsel slap. There was a running change, though. Mine was replaced by JBL with a newer unit.

Quote:
Originally Posted by Efalegalo View Post

Spanish68 - I might do just that --> Cross the JBL W15 to the TC-2000 @ 40hz. Can you please post pictures of your system when you get a chance?

The TC2k is a fairly linear driver, so I suspect you'll get better results by overlapping them and using the two to smooth out response. However, if not there's no reason to highpass the W15GTi, even if you lowpass the TC2k and let the W15GTi handle the upper bass. Let 'em both contribute in the first mode region.

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post #13 of 19 Old 05-24-2012, 01:32 PM
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yep, one of mine has tinsel disconnect on the spider, so i has to solder a new line from voicecoil to the connector. works like a champ. i think you should run the tc2k in contention with the jbl. they have a pretty good low end. they wont disappoint.
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post #14 of 19 Old 05-24-2012, 02:10 PM
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Quote:
Originally Posted by DS-21 View Post

The TC2k is a fairly linear driver, so I suspect you'll get better results by overlapping them and using the two to smooth out response. However, if not there's no reason to highpass the W15GTi, even if you lowpass the TC2k and let the W15GTi handle the upper bass. Let 'em both contribute in the first mode region.

Agreed. 1000%

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post #15 of 19 Old 05-26-2012, 05:02 AM
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"do you think they have the potential to still perform well in the 3 or 4 cubic feet enclosures?"

yes. the big ported was suggested because it gives ~9db more spl in the 16-20hz region and then less as you go up in frequency until they are about the same from 50hz and up.

like others have said, run the jbl full range in the 3-4 cubic foot sealed enclosures, and low pass the other sub around 30-40hz, that way as the jbl is rolling off, the other sub will be kicking in, so the overall frequency response will be flat down into the twenties. by that point, room gain should be kicking in if you have a mediumish sized room.

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post #16 of 19 Old 05-26-2012, 09:42 AM
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Quote:
Originally Posted by Efalegalo View Post

but do you think they have the potential to still perform well in the 3 or 4 cubic feet enclosures? I remember reading somewhere that, given their tremendous power handling, one might be able to get away with a little low-end EQ.

FWIW, I did a test with the W15GTi once. I put in a closed box (I think it was 4.5-5 cubic feet) and used EQ. We progressively put stuff (I think it was books) inside the box to lower the available volume, and listened until the woofer sounded bad. I think the break-point was somewhere between 2 and 2.5 cubic feet. Above that, with EQ they always sounded great. Below that they started to get a little peaky to the point that EQ was no help. That study changed the way I think about Qtc (as long as one has decent EQ available!). Previously I had been fairly fastidious about measuring individual drivers, and building cabinets with Q of somewhere around 0.577 ± maybe 0.5. Now I basically just pick a woofer, decide how much power to throw behind it, and design the box to make optimal use of that power. Still check Qtc to make sure it's not way out of line, but values of 0.8 or even 0.9 don't cause me to break out into hives as they did before I actually listened comparatively.

So, bottom line is, spend less time worrying about the cabinet, and more time making sure you have the right processing and power available.

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post #17 of 19 Old 05-30-2012, 08:30 AM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

"
like others have said, run the jbl full range in the 3-4 cubic foot sealed enclosures.


Just ordered two 3.5 cubic foot enclosures from DIYSoundGroup for my W15s.

Hopefully they will fit in the box - just asked Erich to measure the depth from the baffles to the bracing since the W15s are quite deep (10.25" mounting depth per specs).
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post #18 of 19 Old 05-30-2012, 09:52 AM
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The JBL WGTi series is comparable to a JL W7. Personally, I might even call them just a tiny bit better, but it's close either way. A 3-4 cuft box would be plenty. Make sure it's well-braced. I see you mentioned ordering them but I am not familiar with them, so add bracing if they are not well-braced. The WGTi is a serious driver that needs a quality enclosure if you intend to crank it up.

I also do recommend using a pro amp such as Yamaha, QSC, Crown or Behringer (Behringer only if you're on a tight budget). Personally I'd probably buy a Yamaha P5000s or P7000s if I did this again. Whatever I bought, I would avoid Class A/B like the plague. Way too inefficient for high levels of power in my opinion. Doesn't matter much at low power levels.

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post #19 of 19 Old 05-30-2012, 10:38 AM - Thread Starter
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Quote:
Originally Posted by DonoMan View Post

. I see you mentioned ordering them but I am not familiar with them, so add bracing if they are not well-braced. The WGTi is a serious driver that needs a quality enclosure if you intend to crank it up.

Hi DonoMan,

The following is picture of the subwoofer flatpack that I purchased. I think it has extensive bracing.



Right now I'm just waiting on the designer to measure the depth to the bracing - just to make sure my 15GTi will fit. Will keep everyone posted.
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