my friend was talking to me about what some guy was talking to him about...he said that this guy used a CEMENT box and used a 6 1/2 inch sub and blew away everyone else at a comp, but wouldnt a cement box weigh about 100 pounds??...when i asked WHY THE F**K WOULD ANYONE DO THAT?!?! he said it seals better..my question is has anyone ever heard of doing this or done this? i dont know what cement has that good ol' MDF with a little silicon doesn't...:lala:

 

Well...... that would be some "HEAVY" bass. LMAO!!!!! :sillylol:

Seriously, I don't think it would be worth it, although I can see why it would help. The cement has no resonance or flex at all. That means you would have 100% (or damn close) pure music coming out of that box.

I guess if you wanted to experiment, you could try sheet rock. It would weigh a little less and still be pretty solid. Then maybe use cement caulk to seal it??? I dunno.....

 

How much is 3/4" MDF going to flex?? I use about 2 guns of Liquid Nail in each box I make, This in no open gaps on that.

 

By flex I mean resonate. If you hit the box with your knuckes, and put your ear next to the hole you made for the speaker, you can hear a slight "ring". Granted, it doesn't last for long, but it's there. That's what's known as resonance. The box has a certain frequency it likes, and will either compliment the speaker , or fight with it at that frequency.

If you do the same to a concrete box (it sounds weird even saying those two words together ) you won't hear as much of a ring, if any at all (depending on how thick the concrete is). It would be a dead box, which in reality is what you actually want.

I wouldn't worry about it. Any resonance that is overcome by using a box like that will be very hard to notice in a car. The car itself has a resonance frequency. That's what Dynomat and similar products are made to reduce.

Then there's the accoustical properties of a car, but I won't get into that. It has nothing to do with what a box is made of.

 

yeah unlike what your friend said, a concrete box has nothing to do w/ sealing. a mdf box could be sealed almost as good. it just the resonance property of concrete that makes the difference. i do not think it would be worth it unless the vehicles sole purpose was for spl. otherwise it would feel like you were driving go kart. weight is the main issue.

 

It all makes sence know

 

well if your going for resonance why not make a steel box? i got the metal and a new mig welder. hell it will resonate better then any wood.

 

the point is you DONT want the box to resonate. plus, concrete is less porous than mdf. granted, mdf leaks nothing noticable to most people, but you gotta recognize that spl competitors (especially the expert classes) are trying to get the most out of their equipment. to them, every tiny bit helps. but for me, i'll stick with fiberglass and 3/4" mdf

 

must have been a crappy ghetto competition if he killed everybody with a 6.5" speaker.

i think you're being lied to

 

i just cant imagine why someone would want to go through the trouble to make a freakin cement box when you can get basically the same results from a wood box

 

don't use sheet rock. itz weaker than mdf. u can also use hdf, but the problem is that it is alot harder to work with, instead of splittin it will chip and then u have to start alll over

 

Right. Maybe next he'll enter an SPL contest with a truck full of tweeters.

When your friend knows a guy that slept with a guy's sister that had a roomate who new a guy that did something... chances are it's crap.

 

ROTFL HAHA THAT MADE MY DAY...but anyway, i dont know what to think..i think the guy is just

 

yea? well my best friends third cousins nephews sisterinlaw has a boyfriend that made a box out of lead and blew away the red-neck family reunion with a 5" paper coned sub!

 

i almost fell off my chair laughing when i read that. that's almost as wild as one suggestion i got; packing tape seal the box your sub comes in & mount it in there, a real cool cheap box

 

Actually, a metal box wouldn't be bad for a full out SPL system (SUCK for everything else though). You don't want the box absorbing any of the energy, you want it all reflected out, thick steel would do that pretty well.