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Has anyone installed a subwoofer inside their instatrunk?

TDB55

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I’m thinking about buying a Sound Ordinance B8PTD or Rockville SS8P subwoofer and was wondering if anyone has installed a subwoofer inside the instatrunk? I was thinking about mounting it on the front panel and was wondering about cutting an opening where the speaker would be. Is this a good plan? Or should I just put it under the rear seat?
 

bedhed

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I haven't read into the ways that subwoofers are being installed under the rear seat, so I can't give much info with that. But, I can say for certain that the instatrunck alone will give it a bad sound, unless you fabricate a separate enclosure for the subwoofer to sit into.

Just looking at online images of the instatrunk, I'm guessing there's probably 4+ cubic feet of (unsealed) airspace in there with the gate closed. That's too much for just about any (solo) subwoofer these days. Any smaller than 15 inches anyway. With that much airspace, what you'll end up with is, what I call "flabby" sounding bass. The speaker's cone is plugging along doing as it should, but there isn't enough pressure for it to produce a solid sound.

I'd check the specs sheet for both subwoofers, then plan to build an enclosure for it. With that said, since an enclosure would need to be put in, I wouldn't take up any space in the instatrunk.

To figure up your dimensions for the sub's recommended space, use this:

Length x Width x Height / 1728

Make adjustments to your dimensions until you get the cubic feet where it needs to be. That's for sealed enclosures. Vented is a whole other story.
 
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TDB55

TDB55

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I haven't read into the ways that subwoofers are being installed under the rear seat, so I can't give much info with that. But, I can say for certain that the instatrunck alone will give it a bad sound, unless you fabricate a separate enclosure for the subwoofer to sit into.

Just looking at online images of the instatrunk, I'm guessing there's probably 4+ cubic feet of (unsealed) airspace in there with the gate closed. That's too much for just about any (solo) subwoofer these days. Any smaller than 15 inches anyway. With that much airspace, what you'll end up with is, what I call "flabby" sounding bass. The speaker's cone is plugging along doing as it should, but there isn't enough pressure for it to produce a solid sound.

I'd check the specs sheet for both subwoofers, then plan to build an enclosure for it. With that said, since an enclosure would need to be put in, I wouldn't take up any space in the instatrunk.

To figure up your dimensions for the sub's recommended space, use this:

Length x Width x Height / 1728

Make adjustments to your dimensions until you get the cubic feet where it needs to be. That's for sealed enclosures. Vented is a whole other story.
Would you cut out a circle the size of the speaker in the front panel of the instatrunk?
 

bedhed

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Sure! Doing it that way would essentially be like a subwoofer behind the seat of a single cab truck. If I went that route though, I would build an enclosure that meets the specs of the subwoofer's air space needs. The downside of that would be that you would then have less cargo space within the instatrunk. But, if that's not a concern, then I'd go for it. No doubt.
How close is that panel to the back of the rear seat? Do you plan on cutting out a hole so that the subwoofer surface mounts onto the panel, or cut it out to the maximum diameter of the subwoofer?

Edit: Oh! I forgot an important part in that equation I gave before. After you come up with your enclosure's total cubic feet, you'll need to account for the subwoofer displacement. That number can be found within the specs also.

For instance, if you came up with a total inner volume of 0.5 cubic feet, and your subwoofer's displacement is, 0.25, then you'd simply subtract 0.25 cubic feet from your enclosure's 0.5 cubic feet.
 

ErikOffroad

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Nov 13, 2018
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Texas
Here’s the Rockville 10 inch in my Jeep under the seat. I had to raise the rear seat a inch which I did with some metal and longer bolts. Sitting in the seat it’s not noticeable what I did to fit the sub.

image.jpg


image.jpg


image.jpg
 
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bedhed

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Oh dang. Disregard everything I said before. With those powered subwoofers like those, all of that I mentioned is irrelevant. I've been wondering how those setups do. As you guys know, it's tough to get a decent amount of bass in the TJ. I'd like to try one out though. Just been too skeptical to drop the money for one.

How do you like yours, Erik?
 
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89grand

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Phoenix, AZ
I have that same Rockville sub. Mine is mounted to the tailgate. It doesn't take up any real usable space. Performance wise, it's a lot better than I expected it to be. With the top down, you can't even see it.

0421191311.jpg


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0421191313.jpg
 
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moab

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ErikOffroad

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Ya I will at some point maybe. I like it. It definitely hit the spot with the needed bass in my Jeep. It does lack in some range of bass but it hits pretty good. For the money which was around 110 bucks with a wiring kit I’m impressed. It’s not alpine, but it’s a fraction of the cost in comparison. With the Polk speakers I have and this I think it sounds good. Still excellent with the top off, and is still loud enough to cause permanent hearing damage turned up all the way. If ur looking for a cheap bass solution this is it
 
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Justin S.

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Aug 15, 2018
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Kansas City
This is exactly what I was looking for, and I actually already picked up that same sub. Did you only raise the back brackets on that rear seat? That mounting to the tailgate looks pretty good too. I'd just worry that it would do some descent rattling. Where did you wire in power, did you tap some existing wiring or run it up to the battery?
 

89grand

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Mine on the tailgate doesn't rattle. I put a few layers of sound deadening between it and the tailgate, but I don't think it made a real big difference. In my case, I ran the power all the way up the battery.
 
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TDB55

TDB55

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Mine on the tailgate doesn't rattle. I put a few layers of sound deadening between it and the tailgate, but I don't think it made a real big difference. In my case, I ran the power all the way up the battery.
Where are you going through the firewall with the power wire?
 

Cole

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Mar 6, 2018
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Minnesota, USA
Mine on the tailgate doesn't rattle. I put a few layers of sound deadening between it and the tailgate, but I don't think it made a real big difference. In my case, I ran the power all the way up the battery.
I'm wondering where you grounded it.. also did you just screw it into the tailgate? I've got mine currently under my rear seat, but I take the rear seat out often enough to store other things, and I don't like that being free back there, or having to worry about things slapping the S out of it.