I heard somewhere that the ONE of the best ways to make a sub box is to take flat 1" styrofoam sheets and cover it in fiberglass. Instead of MDF or straight glass. I here it is also very light compared to MDF, so do you guys have any comments on this because that is what i am thinking about doing for my rear seat replacement box. Let me know!

 

TTT

 

I am by no means a sub designer, but I believe the object behind the Mdf is to absorb some of the sound...hardwoods dont work, and by polyfilling the interior of the box, you "trick" the sub into thinking it's a lager enclosure.
It stands to follow that, if you use the insulation as a base to make the fiberglass form, you will essentially have the same thing.
(If you could seal it well.)
Some custom (body)shops use foam to shape and create a panel, or extension of a panel, before laying fiberglass.
Hope this helps.

 

Actually, you don't want the box absorbing any of the sound. You want it all to reflect around on the inside.

The harder the wood, the better. The only reason people use MDF is because it's cheap, and relatively strong for the weight.

A subwoofer box made out of oak would be amazing--ly heavy. Plus it would look stellar.

Every bit of sound energy that is 'absorbed' by the box is completely wasted.

Polyfil is used to cause the sound wave to bounce around longer, creating longer waves... By creating longer waves, it's essentially like having a bigger box.

I don't have any polyfil in my box, because it's actually the right size for my subs---people seem to think that poly-fill is necessary.

 

Solid oak is wat to porus, The biggest reason to use MDF is its consistant. there are no voids and no changes in density. you can use fiberglass but the foam does nothing to help and may even melt due to the resin.

 

Yeah, I didn't even think of the foam melting... interesting.

Why would a pourous material (oak,) matter at all? As long as the air doesn't escape, you should be fine, right? Oak is a much stronger wood, and will not vibrate.

For that matter, wouldn't a titanium box be best?

 

Oak is porus enough that air would escape. In some of the kitchen cabinets I have built when a biscuit or dowel is glued in the wood is so porus that glue travels more than an inched and comes out of the end. Alot of people say use baltic birch with 11 ply if you use ply. But as far as I know and I haven't done any reasearch on this but all ply wood no matter what the outter skin isn't make completly of the smae wood. basically you pay for the outter 1/16" of an inch but also get far less voids in the internal layering if its a cabinet grade.

 

aight no oak... but hard wood is cool, right?

 

only thing i have heard of people using is birch. Never tryied anything other than MDF and cabinet ply for PA stuff

 

LOG!!!! USE A LOG

 

I also belong to a Home Theater forum and in the DIY forum, the guys there always use mdf with a very high quality veneer to dress it up. They all say that a ply or any hard woods do not work.

All of the top speaker manufacturers I can think of in the home industry do the same.

 

When I made my box I just nailed ply wood together then took wood glue to all the seems. Then put carpet foam around the walls and a pillow full of stuffing in the middle. As far as I'm concerned it's good enough. If it's enough to make the wax come out of my ears then I'm satisfied.

By the way, I have two 12" Lightning Audio subs from evil-mart (walmart) powered by a 240 watt amp. Plenty loud for me.

 

picture of my white trash set up.

 

Ive heard of people filling thier boxes with cotton or somekind of soft fluffy material, do you guys recomend that? what kind of effect, if any,will it have?

 

Um, I guess you didn't even bother to read anyone's posts in this thread. Look up about 10 posts (from your post,) and you'll learn something.

Then you won't have to sound like a.. well... whatever...

"soft fluffy material"... Wow...My blood pressure actually doubled from reading your post... Time to go shoot my guns at random cute fuzy animals.

 

Dont know where my head was at, but you sound like your taking that post pretty hard, hope killing somthing makes you feel better. good luck

 

And remember, kids...

Only use polyfil if your box is too small for the subwoofer requirements!

This Public Service Announcement Was Brought to You by the Number Red.

 

Again I am no sub guru, but this, in my understanding, is not entirely true.
Polyfil also helps to absorb the resonance of the box.
My Paradigm home speakers are lined with polyfil, as well as my professionally designed sub.
I actually modded an old cheap HT-in-a-box RCA sub with polyfil. Prior to this, it was boomy and kind of farted out the bass. After, it was quick and tight, quieter, but quicker and tighter.

 

hrm. maybe we need a design guru to step in... as far as I've ever heard, you really only use polyfil to 'trick' a sub into thinking it's in a bigger box... (really you are just allowing the sound wave to bounce around more--growing in size).


I've seen boxes that had so much polyfil in there, it actually made the sub sound like crap.

 

DING DING DING>>.. polyfill is just a band-aid to properly designed box......

although it may be neccessary in some cases
IE: you either cant make a huge box for the crap-woofers you got
or in home theator, you dont want a refrigerator size box for that 15" that you thought you needed


my fiberglass box is plenty big enuff to use for my subs, no poly needed and i was considered the loudest system at school untill my amp got stolen

 

Audiobahn... all shine--no spine!

jk

 

or am I?

 

hey.... ill admit that it may not be the best stuff but i do know that it's loud and has impressed every1 thats heard it....


next set up will be even better.... maybe one adire brahma 15....

 

damn my car is all wrexxed... sigh... I almost don't even have the stamina to make a thread about it... weak.

 

ahhhh weak dude... wat happend... whats the dmg report....

 

Wreck

I think it's worse than these people are making it look like...

hell just getting my front fenders painted (no body work,) was almost enough to 'total' my car! shoot.

I can't imagine getting the entire front end straightened, replace the fenders, hood, bumper, bumper internals, vacuum caninster, vacuum hoses, fog lights, fog enclosures/mounts, headlights/mechanisms motors etc... that crap adds up, espeically at dealer/bodyshop prices.

My only hope is that maybe I can get a check cut to me and they total the car... then I can buy my dreamcar GTA.

it still pains me deep inside, as I planned on having BOTH cars. my little baby, the v6, and my Beast. the GTA. Which I would revamp for more horsepower over the years.

Now it looks like I'll either ditch the v6 and take the money, or spend lots of time, effort, and money, just to make it the way it was before... not satisfactory.

Damn it's confusing. At least it wasn't my fault.

 

gay.... when the hurricanes came last year they wanted to total my maro... for scratchs... on the fenders and the t-tops... it wasnt all that serious... so we said cut us a check that is 1% under total and we keep the car... lol

 

where can you purchase polyfil from?. be easy on me fellas

 

I got a 20 oz bag from Wal-Mart for $2.77. In my local store, it used to be in the A/C section, but has since been moved to arts & crafts.

 

search google...

 

Im to lazy to read all the posts, so here it goes...sorry if I repeat...
MDF is used because it is consistent and lighter than most other wood. The styraphome (sp) thing is, in my mind, bs. The foam would melt, and you wouldnt be able to seal it enough to work correctly. You want a very solid wood that doesnt resonate or flex. Flex and resonation are complete sound killers and since no speaker is more than 4% efficient on any given amount of power you feed it, you want NO wasted sound. The ideal box? Concrete. Zero flex or resonation...just pure sound. Just to damn heavy. Our wells are actually good for building boxes into because the more funky the shape of a box, the better it sounds because there are no parellel surfaces for the sound to refect and cancell on. The only thing I can think of to the foam thing is what we did in class on a 3rd gen...covered the well and whole hatch area in 3 layers of plastic and foil, and then dumped massive amounts of 2 part expanding foam into the well...perfect replica when done. Then we pulled it out, covered it in resin, then mold release, and then layed fiberglass on the foam mold and made a copy of the well off of the mold...lots of work, yes, but worth it...probably. The Box was so light and solid it was amazing. I didnt think it would work but it did...very cool method. The best part? You can re-use the foam mold and mass produce boxes for thirdgens! Yay! Ill have to see if I can find any pics.

 

sorry but i cannot find anywhere online that sells polyfil. Iv heard its pillow stuffing so maybe a crafts store or soemthing?

 

go to a craft store. It's cheaper than air.

 

*whispers* "wal-mart....wal-mart...."

hehehe

 

Wal-Mart would be fine. Probably under five bucks for enough to fill a 3 cubic-foot box.

 

sounds good, thanks fellas. I'll try an arts and crafts store before i go take a 20 mile trip to the only walmart i know of

 

there are like 15 wal-marts in austin... pretty much one every 6 miles or so.... think of cellphone towers... that's how many wal-marts there are.

 

I thought polyfil was like bondo for houses....
that stuff you spackle on holes in your walls before you paint your bedroom sorta thing.... that's why I thought that it couldn't possible do the job (for subs) that I thought it would....
maybe i'm thinking of something else, but I sure wouldn't want it in my pillow...?

 

polyfil is in cheap-*** pillows. I always have pillows made with down.

 

oh, well, your highness


oh ok, so it's that foam/cotton ball stuff?

 

 

It's made out of nylon or something... feels like crap, scratchy and stuff.

Imagine hair-thin fishing line, cut into eighth-inch pieces, and thrown into a cotton-candy machine.

That's what poly-fil is.

 

spackel>> lol no

i have a down pillow... they roxors

 

Yeah there arent too many wal-marts in the boroughs, anyway soo do u just throw a bunch of this stuff into the box or does it have to be glued to the walls of the box or somthing, scrap-maker if this question has been covered already i promise to leave this thread forever.

 

if your box is seal then just throw equal amounts in to each subwoofer hole...

 

Generally, you loosely fill each sub chamber about 1/2 full (I'm so optimistic).

 

.. hmm just play with it.... go until it sounds bad then remove a lil....



and why not just get a properly designed box....