I am currently building a sub box to sit in place of the back seat of my truck and I had a few questions. first being

Is there a max/min of cubic area for 2 ten inch subs"

Also this being a sealed box would it be bad if I put something like fiberglass in the box(I only ask because when I was putting up my surround sound system in my room I took apart one of the speakers for the hell of it and it had some sort of cottony material in it

and also what do y'all recommend sealing all the corners with just to make sure it has an tight seal around all the edges

 

I recomend that you not waste your time on replacing your back seat for two 10" subs just for the fact of- appearence-(you will have this 5 1/2 foot wide bench with 20" of space being subs a big rectangle amp.) not trying to rag on you by any means, Its great that you are trying. I would just hate for you do to this and your budget is too low and when you get done you sau *****! I should of done 4 10's or 4 12's. As for fiberglassing, I can tell your an amature box builder (like myself) and strongly reccomend if you really want to get your hands dirty in a new project, to fiberglass the inside. It wouldnt hurt, but dont be suprised when the materials for fiberglassing cost more than the MDF and maby a sub combined. Dont worry about the cotton on the inside (dont know the technical reason why you dont need it and maby someone else on here can explain but I know you just dont.) Definatly seal all edges of your box with a sealent. there are many kinds out there...bathroom sealent, calk, silicone sealent. its cheap. A tube of it is maby like 3 or 4 bucks. If you seriously go threw with this whole rear seat deal, Be sure you have very good carpentry skills because its not like making a big rectangle with two holes cut out on top. You dont want to invest a few hundred dollars in materials you won't be able to use. good luck if you do though.

 

in a sense it it replacing my back seat in the way that it is replacing the supports that hold up the seat so I am going to put my seat back in and it will just be a bit higher, and I am almost done building it I will try and post pictures of it for criticism when I am done.

I have also read that you dont really need to use fiberglass if you built the box using MDF board but they could be wrong and if anyone has any tips on how to deaden my box or a reason why I should not use a resin to protect my box from the elements let me know I am all ears

and also I ask about sealant because I thought that you were supposed to use a specific one (like it was made for it) but anyways I will probably just use some sort of silicone

also before I completely close it in I need to figure out a way to brace it and make sure it is as solid as can be especially in the middle since it is longish

 

We need a lot more information in order to help you better. What speakers are you building your box for. ie what is the req'd airspace for the subs. Different speakers req different airspace. The list goes on and on.

The fiberglass material that you found inside of the box was polyfill. Here is a quick link as to why fiberfill is used.
http://www.audiojunkies.com/blog/134...osure-resource

I hope you are planning on using 3/4" MDF for your box. Remember to subtract the driver displacement and bracing from the total internal volume of your box. To seal your box you could use different types of wood glue like liquid nails.

With more info we could be a lot more helpful...

 

the cotton was on the inside to trick the subs into thinking that there was more airspace. the sound waves travel slower through the cotton substance making it seem as though the box is bigger.

 

I am building it for 2 ten inch db drive platinum series sub woofers and I am using 3/4 inch mdf I had thought of using 1/2 inch but then I thought better safe than sorry. as for the specs on the sub woofers I am not 100 % because there site is messed up right now. but it is a dual voice coil either 2 or 4 ohms my box is about 6 cubic feet if my math is correct not counting for the bracing or the drivers

if 6 cubic feet it way to much then I can probably save up to add a third

 

Here is a manual for your subs.
http://dl.owneriq.net/0/076513fc-073...d76109486f.pdf

It looks like sealed is 0.6 ft^3 per subwoofer Internal volume, that includes the driver.

So do you want to go ported? 1.2 ft^3 tuned to 35 Hz 3" port diameter and 6" port length.

6 ft^3 sealed will be way to big. Unless of course you want 10 of them.

 

you should use a glue like liquid nails on the seams when you screw the boards together on all joints. there would not be a need to try and seal it inside with silicon afterwards in all of the hard to reach cracks. 6 cu is probally to big for 2 10's in a sealed enclosure would be better to make it a ported enclosure if you have that much space hell i have 4 12's in just over 4cu ft sealed. on the fiberglass resin if you want you can mix it and pour it into the seams inside the box just to make it stronger but if your using 3/4 mdf and you put plenty of glue and screws in it then there really wouldnt be a need. on the bracing internally just cut you some 2x4 or something to fit from side to side and top to bottom and screw them into place and use the glue to help join them to the top bottom and sides of the enclosure just make sure to get everything tight seamed and solid so you dont get rattles and buzzes inside the box. make sure to drill pilot holes with a smaller bit than the screw your using in the mdf before you put screws in it so it doesnt try to split on you.

 

well first of all here are the measurements to double check the volume

L=57"
H=13"
W=14"

since the volume is probably to much for the two subs then what I am going to do is with the remaining mdf I am going to put support in the middle in the form of a wall kind of like a little room with nothing in it and cut the box into three sections

also as far a porting goes how do I do that is there a tube I buy or what and also what does that do for sound and also should it exit out of the side or the front

 

BUMP...

and also

if I was to paint the box in the bed liner stuff would that change the sound and would it be for better or worse

 

With that much airspace available you can put in just about anything you want to. Many people would tell you to put in a massive system. But if you are happy with the speakers you have, that is all that counts. With all of that space you can build any type of box you want.

If you don't feel comfortable building a ported box, keep with a sealed enclosure. Pack it with 1lb/ft^3 of polyfill. So for a .6ft^3 box it would take .6lbs of polyfill. You can get polyfill at most craft stores, or even at Wallyworld. This will give you a basic idea of what you need to make your own box.
http://www.ehow.com/how_4827973_cust...oofer-box.html

Just remember your speakers airspace requirement and build your box around this.

Do a websearch on how to make your own speakerboxes and do a little research.

I have also painted the outside of my boxes with beadliner material before. I found that MDF soakes up a lot of it. Multiple light layers were necessary for an even look.

 

I have no clue why there would be cotton in there. But sounds travels the fastest through the densest medium. For example if you tried talking to someone under water all you would hear is a really high pitch noise because of how fast that the sound was hitting you. Thats also why there is no noise in outerspace, because there is nothing for the sound to travel through. Maybe they used the cotton to change the sound of the speaker. Just a thought

 

The cotton stuff is called polyfil and is used to “fool” or “trick” your woofers into thinking they are in a larger enclosure. I am building an enclosure out of fiberglass and am going to put 3 JL Audio 8W6 woofers in it. Each woofer need a min of .33 cubic feet. When I measure the enclosure (using sand) the enclosure is right at 1.09 cubic feet. IIRC Richard Clark or someone of his knowledge level tested the use of “stuffing” sealed enclosures with polyfil. In his conclusion, the most gains are seen in enclosure < 3 cubic feet and by adding 1.5 pounds of polyfil to a one cubic foot enclosure the woofer will “act” as though it were in a box that was @2 cubic feet or more. The benefits of this in my application is that I get to stuff (3) 8's in my unused area under the seat and get the output close to (2) 12's.