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Old 9th September 2006, 07:00 AM   #1
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Default What to do - small enclosure, odd shape

I think I've read enough to ask an intelligent question now...

Background:
I have a Pontiac GTO (a new one). The gas tank in the car is in the trunk just under the parcel shelf and eats up very much trunk space. I need all the space that isn't taken for golf clubs and moving things between buildings at work. I have a very small box with one Tang Band W8-740C
http://www.partsexpress.com/pe/showd...number=264-854
out of the way, off on the side of the trunk right now and a pair of 6.5" Goldwood heavy duty subs
http://www.partsexpress.com/pe/showd...number=290-307
in the stock location in the parcel shelf. This just isn't doing it for me. I had two wagons before the GTO and had a pair of 12"s in the back of each. I know I can't get that sort of setup in the goat, but I want more than what I've got now.

What I've already tried:
Some guys have been removing the factory 6.5" subs and putting 8"s back there with a little spacer right on the deck. We can't get 8"s any deeper than about 4.25" because of the gas tank (there's a metal brace around it and two tabs that stick up just under the speakers). So our options there are pretty limited because of the depth and because we need IB-capable subs. Most 8"s that I've found are made for small boxes, not IB. Anyway, I got a pair of 8" DVC Goldwoods from Parts Express and they were OK up to about 90W of the 110W they were rated for. Not what I wanted.

A couple people had really talked up those heavy duty 6.5" Goldwoods too. The specs looked good for IB and they were cheap (cheap will be a theme here) so I got a pair and installed them. They absolutely hit harder and sounded better than the 8"s back there, but they just didn't get the lows the way I liked, and they bottom out with less than 100W. I kept them anyway.

Then I did some measuring around the trunk and figured I could get about a .2cuft box over on the side and still have room for the golf clubs. I checked Parts Express and that Tang Band looked perfect. It only needed .16-.18cuft, I only had 150W to give it and that's just what it needed, it was paper (I don't like polypropylene), Fs was very low, huge excursion, etc..(I looked into the RE 8" also, but they were backordered). So I did that and put it by itself in the trunk and disconnected the 6.5"s. It was OK, so I added the 6.5"s back and it really didn't sound any better. So I wired the TB out of phase and it all sounded great. BUT I'm still not getting the SPL I'm looking for, and it's very peaky.


What I want to do now:
We have a lot of volume in our rear quarter panels. Several guys have put 8"s or 10"s in there. A couple have done it with fiberglass, but I'm not ready to do that. The biggest MDF box we can fit is about .5cuft and we can't get a mounting depth of more than about 5.5" (maybe up to 6.5" in spots).
Here's a picture of one guy's setup and his measurements:
Click the image to open in full size.
Click the image to open in full size.


The problem:
Too many options. I could buy another TB 8" and put one in a sealed box on each side. I could buy 3 more and put two each in a sealed box on each side (which would require another amp). I could put one in a vented box on each side. I could put one in a 4th-order bandpass box on each side. I could put one with a passive radiator on each side. I could buy a pair of 10"s instead.

I really don't know which of these is the best option. I really do like these TB subs though and would like to stay with them instead of 10"s. I don't know if there's a downside to using a PR in a car, or if vented or sealed is the way to go.

What I want (in order):
1. Flat frequency response in the cabin
2. Cheap
3. SPL

My thoughts:
I don't know enough about sealed vs. vented to know just which one to use here. I believe vented will take more advantage of the TB's excursion, right? And from the calculations I've done, the size and length of the ports are too big for a small box and makes me lean toward the PR setup (I was looking at the 10" Daytons on Parts Express - their xmax is 10mm compared to 11mm for the TB sub, would that be a problem?). Because the subs will be behind an interior trim panel, I'm going to cut them off at 100Hz or so, and from what I've calculated that would be fine with the 4th order bandpass. I have no idea how that sounds though. It seems to me it would be peaky. Doing two in each side I think is out. I don't want to buy another amp and have to find a place to mount it and do the wiring all over again. I was initially considering just getting 10"s, but I can't find what I want (DVC, 2ohm each, not polypropylene or similar, less than 5.5" deep, $80 or less, works in .5cuft sealed box). Well I did find it in the Cerwin Vega HED10.2, but I can't find them for sale in the U.S. anywhere.

If sealed is better, should I ditch the TB and look for something with a higher sensitivity?



Thanks for reading and thanks for any input. I'm sure I left out some pertinent info and will add it later if I think of it.
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Old 13th September 2006, 02:26 AM   #2
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Nevermind.

I found Unibox. The tiny sealed enclosure is what I want.

Should I have asked over at diymobileaudio.com instead?
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Old 27th September 2006, 11:17 AM   #3
Kenkaru is offline Kenkaru  United States
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You could also brown bread it up to get some more dB's
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Old 27th September 2006, 11:18 AM   #4
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Quote:
Originally posted by Kenkaru
You could also brown bread it up to get some more dB's

And how exactly will adding damping increase the output?
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Old 28th September 2006, 07:02 AM   #5
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The boxes will be tiny. 5.1L max, no fill.
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Old 4th November 2006, 01:55 PM   #6
Kenkaru is offline Kenkaru  United States
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Quote:
Originally posted by pinkmouse



And how exactly will adding damping increase the output?

dB is a ratio so the quieter the surroundings, the more dB you'll get. Ever been in a muscle car with open exhaust and try to listen to the radio?
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