# Anyone done a Jbl Gti IB or heard one?



## trunks9_us (Oct 25, 2007)

I am thinking about doing IB But I have never heard one So I have no idea what it sounds like or how loud it is. But If I was to do this it would be to 2 jbl w15gti's in IB or Sealed enclosure. I would be powering these to subs with a zapco 9.0 which gets pretty loud but how much loudness am I really losing by going IB over sealed? And how much more clarity will I be gaining by doing this as well?

If I would do it it would look like this

http://dtviewer.smugmug.com/gallery/3324033#184988682_59cE9


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## 14642 (May 19, 2008)

They work great in IB and will play louder at low frequencies (below 50Hz) in IB than in a sealed box.


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## poochieone (Aug 25, 2005)

some of the best sub bass i've ever heard was in this car (yes, JBL sponsored).
2 x 15" GTI's each with about 2200 wrms on tap not that they would ever need it i think.
I would be completely content if i could get my 13W7 to sound that good!!


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## WLDock (Sep 27, 2005)

The car above belongs to Mr 2DEEP2 aka Anthony Davis. He is the one I learn from and his claim is the JBL have the best bass he's had to date...He used Image Dynamics products previously. The subs sound VERY nice IB...I like them better that way than sealed. I also heard a member here MuTT or Al that runs a single 15 IB and it sounded pretty good. 
http://i185.photobucket.com/albums/x183/MuTT_MTT/Picture025-1.jpg

My other bud ran 3 W12Gti's ported off a JBL 2200 and I liked the above cars much more.
I would have planned to run a single W15GTi IB myself but the current plans are for a lighter yet capable driver, the AE Speakers IB15-4 Ohm.

I don't how loud you are trying to get but running two of the 15's IB with the power you have will probablly net you the cleanest and lowest bass you have had...provided you DO plan to go the extra step and deaden you rear deck, trunk, cabin, etc. Also, the deck need to be strengthened...two 15's are going to add some serious weight and are going to kick like a mule.


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## MuTT (Apr 4, 2007)

yup, I like mine a bunch.


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## thehatedguy (May 4, 2007)

Anthony's car is awesome.

Dr. Doug's BMW with 1 15 IB is awesome too.

Couple of my favorite cars to listen to. Well, if Anthony isn't rebuilding something in the lanes...lol. Love you Anthony.


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## thehatedguy (May 4, 2007)

Which reminds me...Anthony, have you noticed the phallic image in your trunk?


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## trunks9_us (Oct 25, 2007)

WLDock said:


> The car above belongs to Mr 2DEEP2 aka Anthony Davis. He is the one I learn from and his claim is the JBL have the best bass he's had to date...He used Image Dynamics products previously. The subs sound VERY nice IB...I like them better that way than sealed. I also heard a member here MuTT or Al that runs a single 15 IB and it sounded pretty good.
> http://i185.photobucket.com/albums/x183/MuTT_MTT/Picture025-1.jpg
> 
> My other bud ran 3 W12Gti's ported off a JBL 2200 and I liked the above cars much more.
> ...


Wen you say deaden good on the rear deck how many layers we talking about? I got the whole trunk with dynamat extreme I have used 3 bulk packs in the trunk alone. So I have used 108 sqft of dynamat extreme in the trunk but only 2 layers on the rear deck so thats why I ask. I also have the rear quarter panels filled with great stuff used 28 cans.


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## trunks9_us (Oct 25, 2007)

I am not sure what all needs to be done before doing a IB so could Some one give me all the pointers on what all to prepare for before doing it....


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## trunks9_us (Oct 25, 2007)

Autiophile said:


> Build a baffle, seal off the trunk from the cabin, deaden the hell out of anything that will rattle. Expanding foam is your friend.


Ok you said to expanding foam and deaden the car I went ahead and did this for sq purpose I alrdy shaved off the expanding foam to make it fit 

Here are some pics I have for my current build log I will post in the future.

Check them out and lmk if there is any spots I need to look into or work on....

http://s462.photobucket.com/albums/qq342/trunks9_us/?albumview=grid


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## bassfromspace (Jun 28, 2016)

trunks9_us said:


> Ok you said to expanding foam and deaden the car I went ahead and did this for sq purpose I alrdy shaved off the expanding foam to make it fit
> 
> Here are some pics I have for my current build log I will post in the future.
> 
> ...


A flash light would be handy in this endeavour. You can shine it around areas that you need to seal to make sure you've filled in all holes and eliminated any potential leaks.


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## trunks9_us (Oct 25, 2007)

bassfromspace said:


> A flash light would be handy in this endeavour. You can shine it around areas that you need to seal to make sure you've filled in all holes and eliminated any potential leaks.


I do have a flash light for the pics just look some more lol And dont wry about the duct tape on the box there's a air leaking out from bad cut. And I like my box enough not to get another one done.


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## 2DEEP2 (Jul 9, 2007)

thehatedguy said:


> Which reminds me...Anthony, have you noticed the phallic image in your trunk?


Which one 

The guy who completed the trunk wanted everyone to have proper impression of him and his work.


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## 2DEEP2 (Jul 9, 2007)

trunks9_us said:


> When you say deaden good on the rear deck how many layers we talking about? I got the whole trunk with dynamat extreme I have used 3 bulk packs in the trunk alone. So I have used 108 sqft of dynamat extreme in the trunk but only 2 layers on the rear deck so thats why I ask. I also have the rear quarter panels filled with great stuff used 28 cans.



I cover the whole trunk with Dynamat Extreme with 2 layers on the rear deck lid and 3 layers on the rear deck. The rear deck also has been sandwiched from the top and bottom with 1/8” thick mdf to seal the holes. That was then covered with Extreme making the 3 layers.

My rear 1/4 panels and trunk floor are also covered with 1/2” DynaLiner.


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## trunks9_us (Oct 25, 2007)

2DEEP2 said:


> I cover the whole trunk with Dynamat Extreme with 2 layers on the rear deck lid and 3 layers on the rear deck. The rear deck also has been sandwiched from the top and bottom with 1/8” thick mdf to seal the holes. That was then covered with Extreme making the 3 layers.
> 
> My rear 1/4 panels and trunk floor are also covered with 1/2” DynaLiner.


I see now, Well I have the whole trunk done is 2 layers of dynamat extreme the rear deck is 2 layers on the bottom one layer on top of the rear deck and 5 layers on the trunk lid with expanding foam in the trunk lid it seems to still make vibrating noise with my current ported box I have in there and it still seems to be coming from the trunk lid but I can't kill it I am hoping the noise will be gone if I change to a IB setup since the sub location will be in the rear deck. I can not mat my rear quarter panel These new corolla's have rear quarter panel air bags. So thats why I used expanding foam. I am not so sure how to fully seal off the trunk into the cabin my question is What are some good shops in tx that will help me with this I am pretty ok with driving anywhere in tx with in a 0-300 mile radius I live in College Station. So houston/austin/dallas/ect. If you guys know any good shops that can do a good job making a baffle and sealing it off the rest and will not screw me plz offer up I also have a friend I will talk to in helping me out as he does sq stuff.


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## thehatedguy (May 4, 2007)

Anthony with no love for Will...lol.


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## trunks9_us (Oct 25, 2007)

OK so if I do this IB install with 2 jbl w15gti's and put them in the rear deck I am told I need to brace it real good which is not a problem. Ok so I was reading on another thread not to put to much power on IB installs is this true? I mean the w15gti's handles 800rms which we all know it can take probably 1200-1500 rms but that being said I was planning on using a zapco 9.0 2 ohm version which is rated at 2200 rms which the 9.0's are also under rated. I will be running the 2 w15gti's in a 1.5 ohm load which will be be 2 ohms given the dc resistance. So will I be hurting my subs or install by using so much power? And will IB installs make my car louder deeper or what?


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## 2DEEP2 (Jul 9, 2007)

If you can find it, you can kill it. I use test tones and a rubber mallet to tap on the panels to find the source of the noise.

I pulled my trunk vents and put dynamat on my license plate with a plate holder.

But finding that the vents were a noise source was difficult because they only made noise at a certain frequency.

I'm running the JBL BPx2200.1 per sub (2200 watts) and have not blown a sub in 3 years. I see no problem putting 2200 watts on 2 W15GTi's.


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## trunks9_us (Oct 25, 2007)

2DEEP2 said:


> If you can find it, you can kill it. I use test tones and a rubber mallet to tap on the panels to find the source of the noise.
> 
> I pulled my trunk vents and put dynamat on my license plate with a plate holder.
> 
> ...



How loud was your vehicle? Is it louder than sealed using IB or not as loud. Can a w15gti even take 2200 rms since there rated at 800 I would not think they 3x more than what there rated.


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## MuTT (Apr 4, 2007)

I have a jl 1000/1 running to my single 15gti (IB) and the sub can easily take whatever the amp puts out.

...but I'm not "loud" so take that all for whatever it's worth.


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## WLDock (Sep 27, 2005)

trunks9_us said:


> How loud was your vehicle? Is it louder than sealed using IB or not as loud. Can a w15gti even take 2200 rms since there rated at 800 I would not think they 3x more than what there rated.


Well first you have to understand what JBL is all about and know that the WGTi is a culmination of what they have learned over the years. When most think of JBL, they think of pro sound however, this sub does not stop there. Yes it is efficient, Yes it can handle some power but it ALSO has very good venting and motor cooling as well as audiophile type SQ. JBL actually rates the sub as such:

Power handling RMS: 800 watts 
Power handling Peak: 5,000 watts 

I trust that they were content with the WGTi's power handling as they did not release monster subs to contend with their JBL/CROWN A6000GTi/A3000GTi monster amps that produce 8110 watts and 2232 watts respectively. Also, they offer SPL box plans for the drivers so....

I would say for music listening, the WGTi's should handle just about anything you can throw at them and sound damn good up to some pretty loud levels in the car. Using BIG power is done for the sake of headroom. The guys that posted are both SQ types that want clean bass and don't want their amps to run out of juice when the music gets demanding. Many SQ types like to run reserve power to all drivers just for that fact. Once inside listening to their systems at moderate 80-85 dB levels you really don't notice it right away except that the sound is clean. However, during peaks...It really hits you how hard and clean the sound is. This is where many systems fail and one of many things that seperates the REALLY good systems from the rest.


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## trunks9_us (Oct 25, 2007)

WLDock said:


> Well first you have to understand what JBL is all about and know that the WGTi is a culmination of what they have learned over the years. When most think of JBL, they think of pro sound however, this sub does not stop there. Yes it is efficient, Yes it can handle some power but it ALSO has very good venting and motor cooling as well as audiophile type SQ. JBL actually rates the sub as such:
> 
> Power handling RMS: 800 watts
> Power handling Peak: 5,000 watts
> ...


Well I do understand that which is why I went with zapco amps cause there so clean power wise and I am also planning on buying a bass knob for the amp to control the bass volume so I dont kill the electrical system. Cause we all know that when you have reserve power it means less chance to clip the amp and cause distortion. Which = clean power and signal. Well I am glad to hear the Ib makes subs sound loud at low levels I cant wait to give this a try but I still need some expert advice on who to go to for to do my IB install I would like to go to someone who knows what there doing and does a good job. And I want to make sure it is air tight from the cabin.


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## 2DEEP2 (Jul 9, 2007)

trunks9_us said:


> How loud was your vehicle? Is it louder than sealed using IB or not as loud. Can a w15gti even take 2200 rms since there rated at 800 I would not think they 3x more than what there rated.


I'm not an SPL guy but at my first show with the car I hit 138 dB. My max is 140 dB. I just run the crossover to 80 Hz and crank the gain +3 dB to +6 dB in my crossover. I never touch the amp gains once set.

I've never used the W15GTi subs in a sealed or ported enclosure.

My sealed set up with a different sub maxxed out at 136 dB with 400 watts per sub on 2 15's.

Full range SQ setting I'm flat (less than 6 dB deviation per 1/3 octave) to 107 dB. Above 107 I can get compression at 330 Hz in SQ mode. My system is setup to play up to 115 dB and be pretty flat with the exception of 330 Hz in SQ mode.

In SQ mode the subs never play above 60 Hz and are gained 0 to 9 dB down in the crossover.


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## shadowfactory (Oct 20, 2008)

This thread is giving me a boner, I've been wanting a 15" wgti for some time now and I think I may have to try my first IB setup over sealed, after hearing everything in this thread.


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## trunks9_us (Oct 25, 2007)

Autiophile said:


> Is there a reason you can't build the baffle yourself? No space to work?
> 
> IB really is a pretty easy install and we can help you out if you need construction pointers.


Well its 1. I dont know how to make one and never have made a box period my friend has made me a box but thats it probably was never tuned or made to spec perfectly. 2. People around my area are peeking around all the time I usually have to things at night and ppl sneak around and to suspicious here. 3. I dont have the tools. I am worth trying it out if someone can tell me what All I need to do I have no idea where to begin and What I will need. tools ect. I could try to do it at my friend house since he lives in the country but I would need to know everything on how to do this Plus I dont have the w15gti's yet.


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## trunks9_us (Oct 25, 2007)

Autiophile said:


> You can put whatever amps you want on the subs, but the reality is that you'll never put nearly that much power to them. I had no more than 600 watts on my pair and it was plenty. It simply does not take much power to get low and loud in an infinite baffle and typically the mechanical limits come in to play well before the thermal limits which is the spec you are quoting (800w rms). The Gti series are unique in that as one coil comes out of one gap it is braked as it enters the other gap.



Ok I am a little confused on this quote. You said it does not take much power to get loud and low. Does that mean in a IB it does not produce loud mid bass response? and only really low. I am talking about 50-100 hz range. And You say the mechanical limits will peak before the thermal, Well I am confused on this. Are you saying I wont be able to put more power to this as well because it cant handle it in a IB compared to a sealed or ported? Like the sub says 800 rms in a sealed box the sub can take anywhere btw 1200 - 1500 rms I believe so the sub is underrated. But in a IB your telling me that it cant take more then the 800rms is this what your saying? PLz give me some explanation Since I dont know anything about IB.


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## Oliver (Jun 25, 2007)

Ideally a couple of midbass drivers in stereo and your subs up to about 60 Hz [ done IB ]


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## trunks9_us (Oct 25, 2007)

How much space do you need for one Gti to run Ib?

How much space does everyone have when running 1 , 2, or 3 in the vehicles?

Does it really matter if I have 10x the vas?

What are the downsides if I am not having 10x the vas for each sub?

I only have trunk space of 16.3 cu.-ft maybe a lil bit more or less sites are giving different numbers but like 16.5 and such.

If I was planning on running 3 jbl w12gti's is this still possible with this trunk space?

Plz tell me why I can and explain into detail what would happen if I did....


Edit : Link for the Gti specs

http://manuals.harman.com/JBL/CAR/Boxes and Parameters/W12GTi_rev_f.pdf


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## MuTT (Apr 4, 2007)

Your trunk space should be irrelevant, it's the baffle that's infinite, not the trunk.

basically you're running them free-air with a baffle separating the front wave completely from the back.

you're thinking the trunk becomes the box, in some cases it does, but it shouldn't.

the subs will take a lot less power this way (free-air) but they will also require a lot less power to get the job done.

To answer your question, the amount of space you need to do this is, enough to mount the subs.


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## 2DEEP2 (Jul 9, 2007)

Actual trunk space and Vas does matter to achieve a true IB set up.

Some would say the trunk space need be at least 1xVas.
Most books say 3xVas.

Otherwise, you are just in a large sealed enclosure and not true IB.

Yes, IB means you separated the from front wave from the back. But true IB also means effectively infinite space is being separated. This is why the enclosure spring force disappears

For 3 W12Gti's you want at least 4.78 cuft (1xVas) to 14.22 cuft (3xVas) or larger.

If you use less space the trunk starts to act like an enclosure, so you get a spring load from the enclosure and Qc should go up in relation to Qt.

In a larger box the enclosure spring is reduce to nothing and Qc will be closer or equal to Qt.


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## MuTT (Apr 4, 2007)

I'm by no means trying to argue with you as you obviously know a lot more about this than I do, I think we're trying to say the same thing, you're just saying it so humans can actually understand.
when I say trunk size shouldn't matter, I was under the impression that your trunk should not act as an enclosure, mine sounds no different with the trunk open than it does closed.


2DEEP2 said:


> Actual trunk space and Vas does matter to achieve a true IB set up.
> 
> Some would say the trunk space need be at least 1xVas.
> Most books say 3xVas.
> ...


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## yermolovd (Oct 10, 2005)

MuTT said:


> I'm by no means trying to argue with you as you obviously know a lot more about this than I do, I think we're trying to say the same thing, you're just saying it so humans can actually understand.
> when I say trunk size shouldn't matter, I was under the impression that your trunk should not act as an enclosure, mine sounds no different with the trunk open than it does closed.


rta pleez!


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## MuTT (Apr 4, 2007)

yermolovd said:


> rta pleez!


I've done the rta, not sure if I can grab the results as they are on the fried laptop, but I will try.

there was a different with trunk open and closed before I unblocked the vents.


...and besides, I used the words "sounds no different" for a reason...lol


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## tspence73 (Oct 14, 2008)

Now that is powa! :stunned::wacko::bigcry: Lucky....Jealous.


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