DIY Subwoofer Enclosure for Gen II ST!!

[Carey Frennier]

I'm finally... finally... finally… ready to install my sound system in the 08 STA. I've done some research and got some prices locally. I think I'm going to attempt to build my own sealed enclosure for behind the rear seat. I know my JBL1202D subs won’t fit behind the seat. They won’t even fit without an enclosure! My plan is to pick up a couple SQ designed Kicker 10” subs.



• Does anyone here know a good program that's cheap to help me build a 3d model of my enclosure? Something extremely simple and maybe able to render a diagram for cutting etc etc. I have the google one and it’s a pain in the arse. For some reason it doesn’t work very well on my monster gaming PC, not even with dual Nvidia 8800GTX SLI cards. /boggle.



• Does anyone have a behind rear seat custom enclosure for the gen2 ST? Not interested in the under seat ones.



• I have some basic woodworking knowledge. How does one go about building these boxes? Any tips of the trade?



I'm thinking that there must be more people out there with gen2 units who want a custom enclosure so I'm hoping that everyone with interest or knowledge on how to build one should pipe up!

 

[Carey Frennier]

This is the first box I found that seemed to fit the bill but ...damn...look at that price tag!



http://www.soundoffaudio.com/item.cfm/id/2694



The seller also told me that they sell them loaded with dual Kicker CVT 10" subs. Of course their subs were pretty overpriced.



It doesn't look to complicated!

 

[CobraXP]

I'm putting a Kenwood Excelon 10" in the rear of my '07, but I'm putting it in the pocket storage area (fiberglassing the compartment). I'll remove the door and fabricate a grille/cover to match it. The other area has my amps, inverter, etc, so I can't use that space. If you are using the shallow mount subs, you really shouldn't have too many problems. If you can give me the model sub you are using, I can look it up for airspace and draw something up from measurements off my truck that you could go by.



Are you planning on making a wood only box or are you going to fiberglass it also?

 

[Carey Frennier]

I'd much prefer to stay with charcoal carpeted wood enclosure. It just feels more OEM to me. I'm 90% sure I will be using Kicker CVT 10" subs.



I'm building both an amp rack and a custom sub enclosure. Two individual units so it's easier to adjust and remove. I will be removing most of the plastic cover against the rear wall (including the storage box).



I was actually thinking of setting it up so that the subs are facing the wall with enough room for them to move. Bass isn't a direction dependent wave so it should sound the same either way right?



The reason I want to do this is because I use my back seats folded down ALL the time and I don't want my woofer cones getting damaged or burned out by crap pressing against them.

 

[Clay Campbell]

psycareyo the thing about the kicker subs is yeah they fit in smaller spaces than the regular kicker comps but they also require the same air space as the big one whether they say they do or not. personal experience. so if you use those your gonna probably need more airspace then you have to have them at optimum. thats why i decided not to use them. other than that they are good speakers

 

[TRACket Paul]

Check these out:

 

[Doug Watts]

Like Clay said, the amount of air space is important (the less the better), but your mounting depth is just as important. I have a job 2, so I don't know what the max mounting depth would be for you (I think mine was 5.5"), but start with that and start weeding out the subs that won't work. After you find out what subs will fit, use cardboard to make your templates for the side pieces of your box and middle support if needed. Once those fit, cut them out of plywood/MDF and start framing the box. I used 1/4" hardware cloth to make the basic shape of the back of the box, covered it in felt, and fiberglassed the entire enclosure. I never got around to putting the final cover on it, but that, of course, doesn't affect the sound.





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[Carey Frennier]

Those JL subs seem to be perfect for the insanely limited space requirements. Looks like they average around $200 a pop? Man...that's a ton of money. I think those may be outside my price range atm.





I also have those stupid flaps on my back seats when they're folded down. Those kinda limit space. Thats why I want the cones facing the back wall.

 

[Clay Campbell]

the JL's would be perfect. and i wanted to use them in my behind the seat box but i couldnt justify it for the price. Im waiting on the slim mount S-class memphis's to finally come out. and i took those flaps off my Gen 1 seats two years ago and havent missed them since. you might be able to on the gen 2 as well

 

[Carey Frennier]

How did you take your's off Clay?

 

[Clay Campbell]

if i remember correctly there was a long black piece that attached to the floor right behind where the seats mount. and during one of many attempts to fit some good sound back there that piece got cut up so i just removed it. i think the flaps were attached to that piece or some piece close to there and i just unscrewed em. some one else may be more sure of what they are attached to. but basically i just unscrewed them

 

[Carey Frennier]

Doug,



The back of your enclosure is fiberglass? Was it difficult to join the fiberglass and the wood to ensure a good seal?

 

[Rahul Sharma]

on the kicker cvt's - they are a good sub, but as Clay mentions, you need some space for them. Kicker suggests .8 for each speaker as a minimum upto 3.0 for a max. From personal experience, i have 2 in a 1.3 cuft box, and they don't sound as well as they could. they can handle tons of power, so i know they can do better.

i will be starting a new enclosure tonight using the entire back wall and fiberglassing it all.



Also, after making a fibreglass mould of the back, cut teh front piece out of 3/4 mdf, hotglue it in place with small dowels, and stretch fleece over it all. soak in resin, and lay up some more glass - to the sides, not the front as it is already mdf. it's pretty east that way to attach the mdf to the fiberglass.



Doug - parden the ignorance, but what is "harware cloth"? can you roughly walk me through how you made your enclosure?

 

[Rahul Sharma]

Did some quick research - is this what you mean Doug?



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so did you make a basic spae of the back with the mesh cloth, then cover that with felt, soak it in fiberglass resin? or did you lay glass on that too? I'm kinda curious as to how you went about this?

 

[Clay Campbell]

i built the same style box as RS but instead of doing the fiberglass i took a cue from some builders i know and built the frame of the box first and set it in the truck them fiberglassed the inside of it. It worked out well but when i build my new one i believe what im gonna do is build the frame and loosely stretch fleece over the back and force it into place along the back wall then resin it. i didnt use anything but resin and mat the first time. the pics are in my library. If you have never fiberglassed before i would practice on something else. and make sure you aluminum foil where you glass is going and spray it with pam.

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[Carey Frennier]

"I'm kinda curious as to how you went about this?" -RS



Me too.



Clay- do you have any pictures on you actually doing the fiberglass work? I think I may try this on Saturday!

 

[Clay Campbell]

uh actually i do haha somewhere. let me look for them. can someone tell me how to post a pic that isnt in my library

 

[Carey Frennier]

I bet you got your camera all messy! Thanks!

 

[Clay Campbell]

oka, here is the best one i could find. thats my friend helping me with the brush while i hold the matt in place it would help you to have another person. this is a pretty amature scene here but you get the point.

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[Doug Watts]

Sorry for the slow response guys. I don't get on the site as often as I'd like.



RS, yes that is what I'm talking about.



After I used the hardware cloth to make the form, I covered the back with felt, soaked it with resin, then used fiberglass matting (like Clay shows) and more resin on the inside. On the far left side it was REALLY hard to get the resin to the end so I probably have some air leaking out, but not much. I loosely filled the box with the polyester batting used for pillows too. Also, I used a dremel to trim the black piece that holds the flaps behind the seat so that I didn't have to remove it. For me, the flaps block access to the power/speaker wires and the capacitor.



If I had known the trick for molding the fiberglass to the back wall shape, I would have done that. I just couldn't figure it out and didn't have any friends "in the business" to help me out.