DIY Subwoofer Enclosure for Gen II ST!!

[Kurt Hertel]

Can anyone give me the dimensions of the side panels that they used.... like all the cut outs in the rear and what not

 

[Rahul Sharma]

ST Sails, This is what i did:



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basically used a 3/4 piece of mdf with the dimensions on the left. then in the top right corner, notched out a piece 1.25 inches in, and then fiberglassed it in with the back. it's solid.



my bottom plate is 7 inches wide so the bottom of the side piece is 6.25, as i mount the front plate on the base. i wasn't over worried about gaps between the mdf pieces because i sealed all joints with thin strips of fiberglass and resin (about 7-9 layers).

 

[Rahul Sharma]

also, this is how my front plate is going to look:



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i have mounted them closely as i am flush mounting the subs so they dno't hit the back seat, and the right side as you know has the most depth. there's nothing wrong with the subs being that close, is there? i got suggested that i should put a 2-3 inch divider between the subs as in this diagram:



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anyone know the purpose of it? will it make a difference? help on this would be appreciated before i seal up the box!:lol:

 

[Carey Frennier]

The way I understand it, when you play subwoofers in stereo they each have their own frequency. Mono they both play one freqency. You should not use two subs on a stereo amp in one chamber. If one channel is weaker than the other you could blow the speaker that is getting less power in a shared, sealed airspace.



I'm actually finding some contradicting information on the subject. There is no performance loss with a partitioned, sealed enclosure. From what I've researched for my new build, I doesn't make much difference since no one plays their subs in stereo and if the subs are out of phaze a partition isn't going to help.



Divided it would marginally be more responsive, acurate and tighter bass. That's the point of doing a sealed enclosure to begin with. Sealed enclosure drivers do eat more power because the cone is alays fighting the air resistance it makes. As a side benifit, sealed enclosures rock in small places.



It's also easier to find problems with each sub.



It adds structural support to the entire enclosure.



I'd partition it.

 

[Rahul Sharma]

thanks psycareyo, but i can't seal them off and partition it because the sub on the right side would have hardly any air space? i have them bridged into a 2 channel amp and the intent of using the entire back wall of the trac was to give them the 1.6+ cuft these subs needed....?



what would be the drawback of a set-up like this with no divider or partion between them?

 

[Dingo]

You can partition them and run a wood divider full length of the box.

 

[Rahul Sharma]

I'm sorry Dingo...i don't follow?

 

[Carey Frennier]

If you're saying the subs need 1.6f^3 per sub than you need to double that, partitioned or not.



I'm not really sure what you're saying RS. All you have to do is put one sub on one end and one ond the other and divide the box in half with a MDF divider inside the enclosure and then secure the "top" with the sub cut-outs.

 

[Dingo]

Ugh. I have no graphics stuff on this computer. Picture a divider between the 2 subs going from the bottom of the box to 2/3 of the way up. Now picture another one from the top end of that one to the far side end of the box.

 

[Carey Frennier]

If one sub blows it becomes a passive radiator (a port basically) with very low mass. Low mass means high tuning which means that it will unload below that frequency. That can cause the other currently undamaged driver to bottom out and eventually damage itself mechanically.



Even if it doesn't blow you can still damage them. If they are partitoned that can't happen due to equal and constant amounts of mass.

 

[Carey Frennier]

The design of your box looks like you could divide the airspace just about perfectly and run a mdf divider in the center of the enclosure. Then just mount each subwoofer in thier chambers. I'd probably mount them a little lower than center because the bottom of the enclosure is way bigger than the top. You want some room behind the driver on the inside of the enclosure if you can get it. They say to leave 1" behind the driver for best airflow around the driver during operation.



I hope you accounted for the cone excersion when you fitted them in the truck. Last thing you want is the cone hitting the back of therear seats.

 

[Rahul Sharma]

ok - now i'm LOST! :lol::lol::lol:



OK - if you look at the pictures above you will see that the left hand of the back wall has less mounting depth as there is a motor that pertrudes a bump into the fiberglass. this is not the case on the right side. therefore mounting depth is a problem on the left side.



i'm flush mounting the subs just to account for them not hitting the rear seats. the "top" of my box is only 3 inches wide.



the kicker cvt's can mount right upto the back, as the design allows this to make it even a more so shallow mount.

 

[Rahul Sharma]

Oh, and it's .8 cuft per sub, so 1.6 total. my calculation have this box at about 1.85 cuft.



maybe I should just bite the bullet and get the JL TW5 and a JL 500/1. it's only a $1000:lol::lol::lol:



and Dingo, so sorry, but i just haven't done this enough to understand what you're trying to explain.....

 

[Clay Campbell]

RS/ you can divide the box into to even chambers easy enough just put your divider more toward the drivers side to even out the airspace in both since one side is deeper. I did it to my old mox and it was fine and my speakers were deeper than yours and i sunk them into the box by and inch.

 

[Rahul Sharma]

That's what i'd like to do Clay...i think i'll do this:



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i'm going to add an mdf panel in the middle and partition off the box into two equal chambers, 09 cuft each. then, i'll cut out mdf rings and dowels and position them in place, and glue them down.

Then, strech fleece over each ring, soak in resin and add 7 layers of glass on each one. that should help me get this right. a bit more work, but i think that might be optimum....i just can't get the subs to fit on the left side....



thoughts?

 

[Carey Frennier]

I don't follow your diagram.



It should look like:



[ 0 I 0 ] The " [ ]" is the enclosure sides. The "0" is the woofer ring and the "I" is the MDF divider. It should looks this way no matter what position you have the subs firing from.



Oh nevermind. I see what you're doing. You're not glassing the entire front. Just the woofer area. Pretty good idea imo.

 

[Carey Frennier]

"JL TW5 and a JL 500/1"



I bought one yesterday lol!



I got the JL 13TW5-3 and I don't need anywhere near the space I needed before. So I saved a ton of money and time on the enclosure. I'm doing a single sub instead of the pair I had before.



I'm also making a counter sunk amp rack for my 500.1 and my 60.4. I've not yet picked up the 500.1.



I think it may be cheaper to buy another JBL 300.1 mono amp and just use a pair of 300.1 units.



The 13TW5 says it can handle 500w all day long but its operating range is 300w without stressing the woofer. 600w is almost in it's warranty void zone lol.

 

[Rahul Sharma]

congrats on the purchase! i saw those subs and spoke to the installers who put 1 in an f-150. they said it was unbelievble and couldn't believe it was a shallow mount. it sounded as good as the 12W6 they said. i can't wait for you to put it in so we can finally get a review of this baby in a sport trac....!



and yes, i'm planning on glassing just the ands with the subs - no point in glassin the 4 feet of area when mdf will suffice...

 

[Clay Campbell]

I got the JL 13TW5-3 and I don't need anywhere near the space I needed before.

do you mind me asking what kinda price you got on this sub,

 

[Carey Frennier]

I bought it for $500 incl tax, give or take a few bucks, at Alpha Stereo. Image Audio and Alpha merged businesses here in Plattsburgh, NY. The owner of Image Audio was my go to guy and installer. He now co-owns the other business so he gave me a pretty sweet deal as one of his long standing customers.



I was thrilled to hear about this because Alpha is where I bought my very first sound system for my jacked up 1991 Chevy Scottsdale 2500 454. And my second system in a 96 Dodge Ram 1500 SLT.



After that I went with Image because the owner, Lance, was really helpful and he gave bigger discounts. So now I've got the best of both worlds because they merged inventory and suppliers!



I can't even remember all the vehicles I've had systems in. Of the 12 vehicles I've had since I was 16 at least 7 have had some form of an upgrade. I've always trusted the installer's recommendations and now I really want to branch out and do some of my own work.