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chambering subs in a box

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=27937
Printed Date: June 12, 2024 at 3:18 AM


Topic: chambering subs in a box

Posted By: nyguy4u
Subject: chambering subs in a box
Date Posted: March 07, 2004 at 11:15 PM

I know this question has been answered before, but I still haven't gotten a straight answer, and I need help!!

I have a 01' PT Cruiser.

I have 3 JL 15" W3 V2 subs, and 3 Kenwood Bass amps (subs and amps are the same models).

I'm going to be making a fiberglass sealed enclosure for the 3 subs.

Now, here's the problem.. the trunk in a PT isn't very large or wide. It JUST fits 2 15"s side by side, so i'm going to need to somehow have 2 up and angled in, and one in the middle sort of pushing out so I can fit all 3 back there. I think it's going to be impossible to chamber them off, because if I do.. I won't have any room to chamber the sub in the middle. If my description makes no sense, I can try to draw a pic and post it.

Is it important to chamber off each sub if all 3 subs and amps are the same exact model?. If I need to, I need ideas.. and fast!!! lol

Thanks!




Replies:

Posted By: forbidden
Date Posted: March 07, 2004 at 11:24 PM
Yes the subs must be chambered off, this is part of the reason why we recommended one amp to power all the subs.

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Top Secret, I can tell you but then my wife will kill me.




Posted By: nyguy4u
Date Posted: March 07, 2004 at 11:27 PM
even if I had one amp powering the 3 subs though, your saying I would still need to chamber them off?. So if I need to chamber them off anyways, why does 3 amps, or 1 amp make a difference?




Posted By: forbidden
Date Posted: March 07, 2004 at 11:39 PM

I believe that my original post stated to chamber off the subs or run one amplifier only. (may be wrong and I have been before). Chambering off of subs does many things, for one it makes the box much stronger. With 15" subs you need as strong a box as possible. Next, even though you have 3 identical looking amplifiers, they are in fact far from identical. The efficiency of each amp will vary, the parts used will vary, the crossovers will vary and the gain pots will vary. You need to have a O-scope to properly set the crossovers and the gains. When 3 subs can interact with each other, when being driven by 3 amps, you can ultimately cause a failure of one or more drivers, especially if the drivers are working against each other because of the different tolerances in the amps.

Imagine your vehicle and trying to calibrate 4 engines to the 4 tires, how succesfull would it be and how long and hard hard would it be to make it work properly. 



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Top Secret, I can tell you but then my wife will kill me.




Posted By: skylark
Date Posted: March 08, 2004 at 12:49 AM
whats the best amp out there to power the 15's dollar for dollar

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goingcrazyonsound




Posted By: turbod16y8
Date Posted: March 08, 2004 at 11:50 AM
what ohms are the sub at?  each

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Two 13JLw6v2 PPI 2350 Alpine 7995 MB quarts




Posted By: nyguy4u
Date Posted: March 08, 2004 at 5:22 PM

Each sub is dual 2 or dual 4 ohms.. depending on how it's wired. I guess i'll wire in parallel.

Ok so i've come to the conclusion that I need to chamber off my subs then. Next question is, how?. The trunk isn't all that wide, so how can I position the subs to get a good chamber for each?. I was planning on one to the left and one to the right of the trunk, up high, and sorta pointed towards the middle, and the 3rd sub in the middle of the box pushing out towards the trunk lid. I am stuck tho on how I can chamber the subs with one of the subs being in the middle of the box. Any ideas??





Posted By: nyguy4u
Date Posted: March 09, 2004 at 8:32 AM
anyone?




Posted By: Ravendarat
Date Posted: March 09, 2004 at 8:50 AM
to answer your other question I had the same problem trying to put 4 power hx2 into the back of a 2003 accord. My solution is to invert them all. If you invert all the subs you should be able to chamber the box and fit all the subs without much problem




Posted By: nyguy4u
Date Posted: March 09, 2004 at 9:25 AM

Ok I attached a pic, I know it sucks, but at least it will give some idea of my problem..

posted_image

Ok so, 1 and 2 are sorta facing the middle facing up, and 3 will be in the middle, facing out. Regardless of how they are facing, 3 will be in the middle. Problem is, that is where the chamber wall would be to chamber off 1 and 2. See what I mean?. So, I think it's totally impossible for me to do that set up. The only other solution I can think of, is have 3 subs in a triangular fashion, like this...

posted_image

Now to do that, I would have the room, and each sub would be properply chambered. Only problem is, all 3 would be facing the trunk, and i'm afrain of major rattles, even with Dynamat.

Any ideas or suggestions??





Posted By: nyguy4u
Date Posted: March 09, 2004 at 10:15 PM

I noticed the pics didn't post. But you get an idea from my description.

Any ideas?





Posted By: nyguy4u
Date Posted: March 11, 2004 at 2:00 AM
anyone???




Posted By: forbidden
Date Posted: March 11, 2004 at 1:21 PM
When I have some time to sit and go through what you have I'll be glad to do it. Get the pic's to post or e-mail them to me. forbidden@telus.net

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Top Secret, I can tell you but then my wife will kill me.





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