Advice on subwoofer install?

I got my hands on a Bill Jehle console woofer enclosure (the one here: http://www.billjehle.com/PORSCHE/console.html ), but as I fish around behind the carpet, I'm not quite sure there are any bolts there that I could use. I have a 996 coupe without the Bose system. Has anyone used this enclosure? Do I have any chance of getting it in there, or should I give up and go look for something else? I am hypothetically not averse to drilling into the transmission shaft, but I'm not entirely convinced it's a wonderful idea. Been looking for a woofer setup that doesn't detract from the already limited interior space, and thought this would be a wonderful idea - wondering if I overstepped here. Thoughts welcome. Thanks a lot!

I do not know if they fit under the seat in a 996, but you might want to check out underseat subwoofers. I wanted low profile subs to put together a stealth audio system hidden in the joists of my basement, but I couldn't find any home audio subs that would fit, so I ended up using two underseat car subs driven by an AC-powered heavy duty 12v DC power supply. These shallow subs put out a surprising amount of bass. The first one I put in was this: Amazon Amazon The second one I put in was this (which I thought would be better because it is 10" versus 8", but I actually think the cheaper/smaller Planet Audio sub above sounds better): Amazon Amazon Both are ridiculously inexpensive considering that they have the amp built in and they both put out a lot of bass. Unfortunately I have no idea whether they fit under a 996 seat, but I think this would be a great stealth sub solution if they do fit.

Has anyone who has deleted the rear seats built or found an enclosure that fits in the back in lieu of the seat bottoms and backs?

Just get an OEM sub enclosure from a cab 996 with matched carpet. It will look much better than the one you have linked and with the right sub they can sound halfway decent... never better than a pair of good 8's or 10's in the back... but decent nonetheless.

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But won't I have the same problem, ie the mounting points aren't there? It goes in the same place in the cab, doesn't it?

Dunno... I'd assume they're in all of them but if not I can't imagine it's that hard to figure out a way to mount it up.

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Right.. that's kinda my problem though, right. The Bill Jehle one mounts directly into the same mounting points, so if I did figure out how to mount it, I'd be home free - but having fished around the transmissions shaft, I can't seem to find any bolts. Wonder if, since the coupe never has a woofer mounted in that location (and Bose just mounts behind the rear seats), there's just literally nothing there, and I'd have to drill to get anywhere.

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This is actually an interesting alternate option, since the under seat space is wasted anyway, not like you can put feet there. I really, really wonder if these would fit. Could maybe even put a pair of these under both seats.

There's a company called CAI that used to make custom sub boxes that fit behind the front seats on the floor facing the driver's seat.

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Yup, saw those. But can't give up rear seat space, I regularly carry passengers... trying to make lemonade here.

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Silly question, but have you tried asking Bill Jehle how it should be mounted?

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Yup I have. He mentioned drilling, velcro or brackets. I'm not excited about any of those There's always a wealth of genius out on the Internets, though, so was hoping someone would come out and be like, dude, just ziptie it to XYZ spot.

2nd on CAI, I have been to there store and they can make any enclosure you want. They make them to fit in same location as the Bose but with your favorite speakers that would not fit in the Bose box. In addition, the box you have shown may not have the proper internal space to get the proper sound (frequency) out of certain speakers.

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Velcro sounds like a crazy idea, but if there is enough vinyl that you can attach to (it looks like most of the area it attaches to is carpet), then this Velcro ( http://www.homedepot.com/p/3M-Scotch...6741/205520125 ) is unbelievably strong. It isn't really velcro with fuzzy stuff on one side, but instead is more like interlocking plastic strands (both sides are the same). The adhesive they use on the sticky tape side is also really strong. Once you've mounted something with this stuff, it takes quite a bit of force to separate it. It will come apart, but it requires probably 10 times the force of normal velcro to remove it.

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+1 I think you are in good shape if you use strong velcro and adhesion promoter on the carpet before you attach it. If you look at these amplifier instructions from CAI, they use adhesion promoter and velcro to adhere amplifier mounting plates in the trunk. https://cai-store.com/pages/996-c4-a...r-installation Your subwoofer box has two areas of contact (floor and side tunnel) which should be pretty secure. Even if it somehow gets knocked loose, it's in the passenger footwell and can't do any harm there. If the amp gets loose in the front trunk, then you may be calling the painless dent guy or looking for a new hood. So I think the velcro and adhesion promoter must work pretty well. Adhesion promoter link below via Amazon: Amazon Amazon All you need is for the box to not move when cornering or if it inadvertently gets kicked. Velcro should be more than strong enough. I would not suggest using the OEM subwoofer cabinet - "boom city". It is simply terrible and creates boomy bass. You have a very elegant sealed sub with the Jehle box that should be orders of magnitude better in terms of sound quality. Finally, if you remove the snap in trim panel on the side of the center console (in the circle in the below picture, you may be able to attach some kind of metal strap from the back of the box to the structural metal underneath the trim panel if you are really paranoid. I would just use the velcro and be done with it. I can't imagine you are going to need anything more than that. Just use the adhesion promoter and be generous with the velcro, you should be fine. Best of luck and please post pictures of the install when you're done!

I went a different route: https://rennlist.com/forums/996-foru...l#post14148639

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Thanks. That's solid advice, appreciate it. I wonder, though - how much will it screw up the floor carpeting for the eventual day when I need to sell the car? There's someone local selling this thing: https://page.auctions.yahoo.co.jp/jp/auction/v507012524 I'm sort of semi-wondering whether I should switch to that setup. The speakers are probably garbage, but the Audison SRX2 could maybe be used to drive a pair of woofers? But I'm sure the Bill Jehle setup is better - the box feels MEGA solid. So maybe you're right on the velcro there. Ooh. Thanks for the pics, especially of the firewall. Did you have to drill the firewall for the cables or was just cutting the trunk liner enough? [edit] ah wait. you had the CD changer, i bet the holes were already there, doh.

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I'd probably just use some kind of 3M adhesive remover and call it a day. Besides, whoever buys your car will probably want the upgraded audio system that you are installing. You won't want to bother putting it back to stock and the OEM system is just that bad...

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Does adhesive remover work on carpeting though?

There are large gromets in place to pass the wires through. For the frunk to the area by the battery, I did not realize there is another one inboard of where the frunk wiring passes.....because mine is a C4 and didn't see it, but it's just like the firewall one.

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From the CAI amplifier installation link that I posted above "Your kit also has a packet of 3M brand adhesive promoter. This adhesive promoter is not a cleaner and is critical to the amplifier rack installation. Apply the adhesive promoter to the entire carpeted area that the amplifier rack will be mounted to. Allow the adhesive promoter to thoroughly dry (10 Min).The adhesive promoter will dramatically increase the holding power of the Velcro to the factory carpet trunk liner."

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Whoops, I missed that - sorry. Guess I'm really not removing that sub once it's installed without replacing half of the car's carpet, eh.

I'm not a fan of adding things to the interior that don't belong there, especially when those things are held in by velcro. I kept my 996 looking 100% stock, yet managed to get the incredible sound of a custom stereo. There's incredible subwoofers and speakers that are made for the 996, they fit right in the existing factory spaces. If you want to read what my car has in it, you can do that here: https://zerotoflatsix.com/2017/04/13...and-played-on/ Believe me, the sound I get from my car is pretty unbelievable, and it doesn't look any different that when it left the factory (other than the PCRN head unit, but that's a Porsche part).

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Yeah, I see what you did with the door speakers. This is another route I was considering going, but I'd need to source new door panels (not too bad) but then run wiring through doors and so on, which I'm not keen on doing as I've read it can be a bit of a pain (my car didn't have door speakers originally). I agree I don't like to velcro stuff in, so I'm still a little bit on the fence with that rear shelf speaker setup I linked to - I'm sure they're not good speakers, but for $200 or so, I could at least avoid the hassle of having to build the enclosure and it would fit relatively neatly into the existing shelf space. Hm. Decisions.

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Oh, my, didn't realize you have the regular door panels! Yeah, that would be quite an undertaking. I used to have a Boxster (986) and the previous owner had actually cut holes in the standard door panels and installed a set of speakers, running wire through and everything. He did a pretty spectacular sh*t-show with it as he also cut through the weather seal. I discovered this when I was investigating why the speakers didn't work. Turns out, rain seeped in through the huge holes in the weather seal and rusted the speakers over time. Since the Boxster has the same door panels as the 996, I'd advise against doing that! I did, however, find new door panels for it here on Rennlist (mind you, that was 6 years ago). Funny thing was, I had a very hard time finding regular door panels without speakers, I could only find door panels with speakers. Since I didn't want speakers there, I just wanted the normal door panels. Fun times. Anyway, good luck with whatever route you decide to go!

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when I bought my car the back seats were removed and a custom box with 2 subwoofers was in its place. I removed them right away.

I'm not super enamored with putting subs in to replace the door woofers. I replaced my door woofers with Tang subs and, while they put out a lot more bass, they are a bit overwhelming for the door enclosure. Also, because they are a true sub instead of a "woofer" as the original door speakers were, it requires some EQ tweaking to get the upper bass filled out. If I were to do it again, I would have left the door woofers in place and found a stealth way to add a dedicated sub. The factory door woofers are actually fairly high quality when you look at them, unlike the factory dash/rear speakers which are pretty low qaulity.

I�m thinking of having a box built that sits in the area where the cabriolet top sits when the top is down. Two obvious downsides: 1.) Better not ever forget to keep the top up before removing the sub for stowing in the frunk. 2.) Cannot have bass when the top is down. Otherwise, I was going to have a box that sits in the floor of the passenger footwell and floor. There is between 0.6 and 1.0 cu ft of interior space, which would suit my 13� JL TW5 sub. I decided the rear space where the cabriolet top fits is just not big enough, and not really going to be a fun place to have to get into to remove the subs.

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Don't do it in the footwell, unless you never have passengers. I got a molded sub install for my footwell and it was a nightmare, there was like no foot space left for passengers. I switched to a rear shelf setup instead and it was much, MUCH better.

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Always a popular topic...+1 on using the Kicker SWs he refers to in that link. I have a cab (no parcel shelf area per se), so room is an issue. Here are some picks of how I worked it using a home-fabbed board to create an application that occupies about the same space as the stock door enclosure. The main pic is partway through the installation, I further trimmed the expanding foam a bit on the right side of the pic. The last pic shows some of the test-fitting into the door panel. Yeah, I know, this isn't all that pretty or perfect, but it is hidden and works well without buzzing or other issues. The bass is best described as tight and accurate, not truly loud; these Kickers aren't that big, and can be overwhelmed by intense, deep bass if you are into that. This is plenty good for me, but I wouldn't dissuade anyone from trying that Jehle passenger footwell enclosure instead of or, even better, plus these Kickers, when using mid/high-range speakers in the regular locations.

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I went with an OEM Bose sub from a 2003 Cabriolet that I bought on ebay. I removed the 4x6 Bose speaker and sealed up the speaker opening and port with Plexiglas and silicone sealant. I did some research and ended up going with a JL Audio 6.5" sub which fit in the depth of the box (with a spacer) and was appropriate for the volume of the box when stuffed with polyfil. Very happy with the sound and it blends in well with the factory carpet and location. Plus I was able to mount it to the floor in the factory location so it is secure. Obviously would not work with a 13" (!) sub but you could also considered a shallow mount 8" sub. The problem is that there really isn't a large enough flat surface on the side of the box to get a much bigger sub in there even if you wanted to.

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Back in the day (a long time ago...) I bought 8" bazooka tubes for my Mitsubishii Conquest TSi. What a fun car! For the 996 cab, I removed the back seat bottom cushions, folded the seatbacks down and fastened the subs underneath. I rarely have backseat passengers. I too had the rear footwell fiberglass enclosures, but was never satisfied with the SPL from them. Earthquake 8" were about the only ones that would fit.