Concrete Sub Box

I have a 95 Nissan Kingcab, putting 3-15" powerbass extremes in the bed firing thru a crawl through. The guy that designed the box told me to put sonotubes (16" concrete forms for pouring cylinders) inside the box. The box is sealed and the corners have been fiberglassed so that they are curved instead of square, the outside of the box is concreted. Has anyone seen this design before or had any luck using the sonotubes. I've built lots of boxes but have never seen the use of tubes inside a sealed enclosure. Thanks for the help guys!

wouldnt a concrete box weigh ur car down a ton?

ok, this guy who used concrete.... does he have a clue what he's doing? Concrete is like OldSkooL sound deadener used back when my dad did this kind of stuff. Concrete shouldn't be in installs nowdays as its 1)too freak'n heavy, 2)hard to work with and 3)not as good at what its suppose to do as actual deadnener like Dynamat etc. And why he wants you to put tubes in your box well my only guess would be that he either didn't use internal bracing and just didn't tell you that the box is weaker then it looks, or that he made it too big and needs to fill air space. Seriously recheck this guys stuff as it makes not sense to me.

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"Shiny chrome when used in conjunction with bikini models is particularly effective in inducing brain deficit disorder"

02 Jeep Grand Cherokee

Monster System on its way.

I'm guessing the box was designed to imitate a tool box and extends from side rail to side rail in the bed, so the forms are used for both structural support and to take up air space.  And is this a design, not an actual built product?  But you can't connect the bed to the cab, because a truck flexes at that point. 

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

not always....grin

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ah, a slick grin coming from the guy who's building a sub enclosure into the a truck cab from the bed at the meeting point haha.

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"Shiny chrome when used in conjunction with bikini models is particularly effective in inducing brain deficit disorder"

02 Jeep Grand Cherokee

Monster System on its way.

https://www.io.com/~patman/sunosub.html

sonotube sub use for home theater using 2 shivas from adire audio...known as the water heater.

Use in car audio..and inside a box is puzzeling.

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I need quality equipment, feel free to donate.

Don't put concrete in a box, especially if its not secured (or else it'll be bumpin and grindin like R Kelly, on your sub, and no, thats not a good thing). If you need to fill airspace then use some mdf and just screw it in layers on to the back or sides. Also I would definitely consider bracing your box (it's a must for SPL applications especially).  

The form tube is not made of concrete, it's used for making a concrete post.  The tube is fiberboard.  It's the concrete on the outside of the box that I wonder about.  I would only guess that it's a thin layer trowelled onto a wire mesh to form the curved lines and protect the box from weather.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

so this guy hasn't heard that fiberglass is weather resistant or something?

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"Shiny chrome when used in conjunction with bikini models is particularly effective in inducing brain deficit disorder"

02 Jeep Grand Cherokee

Monster System on its way.

u guys do know that concrete is used today in spl right? not for the enclosures, but for makin stuff not rattle. anyhow, if u wanted to be really tricky, used aluminum. weld it together. it doesnt rattle at all. then use some truck bedliner to make it match the rest of the bed, and no one will ever know its there... minus the big bulge... yea, u get the point.

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1990 Honda Civic HB:
Clarion DXZ545MP H.U.
2- 6.5" Power Acoustik interiors
Diamond Audio 600.1 amp
Diamond Audio 15" M6MKII
Pyramid PB881X 4 CH. Amp

This van used concrete walls (just scroll down). I'm confused about this topic. The outside of the enclosure is covered in cement. Had it bonded with the enclosure, wouldn't it keep it from flexing?

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Jon
Don't like rockford subs? Then don't look at my car =)

I am assuming he use concrete tokeep the box from flexing which would be very fectve. I dont know any sub that is gonna make a 3/4 mdf box thats encased of an inch of concrete flex. When ever I have seen concrete used it was to stp flexing, and it is very effective at it. THe problem with it is the sever increase in weight that it adds to the vehicle.

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

there is a group of home theater people who are using marble and concrete to make sub enclosures, the reson is it doesn't resonate (well at least not at any frequency that will color teh sound) that will make for a truer sound fiberglass and wood add some sound to the bass

Well the box was designed by a designer who works at powerbass. The concrete keeps flex down and cuts down on the resonance of the box. Weight isn't really an issue if you are a serious competitor. The tubes inside the sealed box are supposed to make the box act like it is ported and make it hit harder. NOT because the box is too big. Box for 3- 15"s is 8 cu ft. My ported box for the cab is 13.2 cu ft for 4 subs and it is almost 6 cu ft shy of what it really needs to be. Well anyway I constructed the box and did a test run with it. In conclusion after 3 hrs of trying to get it to hit harder than it did with my other set-up I came to the realization it sucked and is going to the trash pile. Gonna make a few mods to my other box and run it for this weekends comp. Thanks for all you input and links.

yeah, interesting topic. Sorry I sounded so pissy, I'd just never heard of concrete being used inside a sub box or for weather proofing resons. I have heard of people using it to stop flexing, I hadn't head of its anti-resonating effects, very interesting. I learned something new today

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"Shiny chrome when used in conjunction with bikini models is particularly effective in inducing brain deficit disorder"

02 Jeep Grand Cherokee

Monster System on its way.

No problem, it's all good, I put my old set-up in last night for Sunday's comp so I'm good to roll. I think I will tinker with the junk box and try to tune it with maybe shorter tubes. It sounded damn good till you threw alot of power on it and it started to clip extremely bad, sounded like all three subs were shot. I had it hooked up in the shop and think it may be mostly a voltage problem, amps draw a lot of juice. Power supply might not be as big as it was supposed to be. It'll be something to do this winter anyway.