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LoudCrownVic
02-03-2004, 08:22 PM
Why is it essential to use MDF in a subwoofer box? Would it be okay to use some plywood that I have lying around?

Wonderbread
02-03-2004, 08:23 PM
Not recommended. Plywood is no where near as sturdy as MDF. MDF will not flex, given appropriate contruction. Also, plywood will resonate. Resonate = bad.
Will not be as solid, last as long or sound as good.

nweibley
02-03-2004, 08:36 PM
MDF is stronng, dense, consistant, and easy to work with. It is readily available, and very easy to manipulate. It is pretty durable too, excluding water. It is extremly smooth, and resists deterioration a little better too.

Go spend $20 and get a 4' x 8' sheet of MDF imho...

95RAM
02-03-2004, 08:40 PM
its only 20 dollars. tats pretty cool i could make my whole box with that

LoudCrownVic
02-03-2004, 08:43 PM
I'm not fighting anybody's advice, but the plywood is sort of like regular wood just thin sheets of wood glued one ontop of the other. And... Would'nt box stuffing or dynamat inside the box (which is probably not kosher) cut the resonance?

nweibley
02-03-2004, 08:45 PM
It would all help, but it is not quite on par with what MDF is. It just isnt quite as rigid. If you cant get a sheet of MDF, plywood would work I guess... but MDF is doing it right, and you might as well do it right once...

95RAM
02-03-2004, 08:54 PM
although if you have extra plywood lying around you could practice on that before you buy the mdf and start cutting away

LoudCrownVic
02-03-2004, 08:54 PM
Sweet! I'm sad that l'll have to spend money, (Ill need at least 3 sheets) but once is better than twice and 60 bucks the second go round. Plus, does dynamat work as a replacement for box stuffing? I could be more accurate with cu inches if it does...

Wonderbread
02-03-2004, 09:08 PM
why will you need 3 sheets?!
they come as big as 4x8 feet!

LoudCrownVic
02-03-2004, 09:17 PM
why will you need 3 sheets?!
they come as big as 4x8 feet!
I'm building a massive ported box for my Crown, 38x17x15" and have numerous other weekend projects that need to come out of the walmart boxes. But first... I needed some advice!

bumpin_8605
02-03-2004, 11:16 PM
one like that should take 1 maybe 1.5 sheets max thas not a very big box. jus plan ur cuts out first

runningame21
02-04-2004, 10:55 AM
Yeah, my box is 39" x 16" x 20", and I used only one sheet of MDF.

B_Master_Flash
02-04-2004, 11:04 AM
I am making my 30"x20"x17" box out of one sheet (already have the cuts lined out) as far as using dynamat inside the box, what are you trying to accomplish? Polyfill is used to make a box seem bigger (I have no idea how it works) but I have never heard of using dynamat.

ssj2xxgotenxx
02-04-2004, 12:14 PM
One sheet is hella big~! 1 foot = 12 inches remember. A 4x8 sheet won't even fit in the back of my dads tundra so....

B&R Innovation2
02-04-2004, 12:25 PM
First. MDF has acoustical properties that you wont find with plywood. It's not nearly as pourus which is very important. When you get a chance stick your head into a plywood sealed box and yell...and then do it in an MDF and I think you'll quickly realize why people use it. I've made plywood boxes when I was first getting into this stuff and they were positivly horriable.

Don't use dynomat inside...its niether cost effective nor effiecent. The point of polyfill is to slow waves from bouncing off the inside walls which will extend any given basshit and make the box seem bigger. Dynomat will obsorb the sound. Also if you do decide to use plywood...paint the inside of the box...regadless its not anything that MDF will be. Plywood is what I'd call LDF.

As for your box size...mine is 16 cubes and it took 2 1/2 pieces precision cut and well thought out. If you buy it at a home depot they'll make cuts for you so if you think it out well and have them cut sizes you need you can save yourself some home cutting time plus you'll fit it much easier into your car.

Benny212
02-06-2004, 11:30 PM
ok I got why plywood *****, but what about particle board? why isn't that used?

packerfan
02-06-2004, 11:35 PM
Partical board works, ive used it plenty of times.

zane
02-07-2004, 11:05 AM
VC Baltic Birch Plywood works excellent for building speaker enclosures. In fact, many prefer it to MDF as it is a bit lighter, and easier to work with. Also, doesn't create near as much sawdust as MDF. Density wise, it is equal to MDF. Several of us on SIN are using the Birch Plywood now for our own enclosures with great success. Only downside is, it is slightly more costly.

Home Depot, Menards, Lowes, all usually carry VC Baltic Birch Plywood.


Particle Board usually isn't the best to use on enclosures, as it is somewhat porous.

However, I personally believe that with a coat or two of resin, and a coat of Auto Body grade clear coat, that it works just as well as MDF.

DCMax22
02-07-2004, 12:51 PM
MEDIUM DENSITY FAILURE (MDF) or particle board--A panel or core product manufactured from wood fibers combined with a synthetic resin or other bonding system. Warning: May cave, crumble, or flake to pieces. Not recommended for extended life professional sound systems.

Acidburn
02-07-2004, 04:16 PM
how would 3/4" particle board work with being sprayed with a sealer like a rubber undercoating?

zane
02-07-2004, 04:31 PM
MEDIUM DENSITY FAILURE (MDF) or particle board--A panel or core product manufactured from wood fibers combined with a synthetic resin or other bonding system. Warning: May cave, crumble, or flake to pieces. Not recommended for extended life professional sound systems.


MDF and Particle Board are two entirely different things.....

helotaxi
02-07-2004, 05:15 PM
MDF and Particle Board are two entirely different things.....
Exactly. MDF is the stuff your high quality home cabinetry is made of. Particle board is the stuff low grade WalMart furniture is made of.

tommyk90
02-07-2004, 05:18 PM
Exactly. MDF is the stuff your high quality home cabinetry is made of. Particle board is the stuff low grade WalMart furniture is made of.

Haha, that's classic.


In the sig it goes ;)

DCMax22
02-07-2004, 05:28 PM
MDF and Particle Board are two entirely different things.....
Maybe in theory, but not in definition. MDF is a better grade of particle board. You would have to be on crack to make a sub enclosure out of particle board. But it is all shavings mixed with glue, not as strong as pro grade plywood, but then . . . it does not have to be unless, that is how you are livin . . . . .

EarDrummin.
02-07-2004, 07:38 PM
Maybe in theory, but not in definition. MDF is a better grade of particle board. You would have to be on crack to make a sub enclosure out of particle board. But it is all shavings mixed with glue, not as strong as pro grade plywood, but then . . . it does not have to be unless, that is how you are livin . . . . .

This is going nowhere..

Chance89
02-07-2004, 09:10 PM
u guys are gonna mke fun of me...but my box if made of 3/4 plywood. It's behind my seat so no one see's it. I don't find that big of a diff in sound. It's a little softer bass that hard and punchy and I like low. It's easier to work with because your cuts don't have to be exactly exactly on beacause it gives. But If I got 2 more 12's I'd build my next box out of mdf. I say build your box out of mdf. It'll be a nice smooth surface and hard hitting bass.

scottrc5391
02-08-2004, 12:01 AM
Supposedly MDF, as already stated, is stiffer (resists flexing so theoretically it should yeild slightly better/louder sound, is smoother (for better fit and finish), and is denser and therefore a lot more airtight than standard plywood. IMO, 3/4" plywood is just about as good if done right, and it seems to me like it would be the stronger of the two. Just make sure you don't use bowed boards and cut it really well. The use of a spray-on sealant to the insider renders it pretty much airtight like someone already said. BTW, why would you not finish a plywood box or MDF box by carpeting, etc.? Appearance should be no way to compare the two because nobody should leave their box bare. I also figured MDF is heavier, correct? Ahh, what the heck, just use fiberglass if you can do it.

Try2makeitwork
02-08-2004, 02:03 AM
I made 2 boxes out of plywood that i had lying arond and i didnt have room for 3/4 inch mdf the box was for under my seat and it measured 12"w 13"L 6"Tall in front and 4"inches tall in back so i dintt have much room to spare i put a 10" MTX 8000 UInder each of my seats and ram them off of a 600 W Lanzar amp, And i have to say it sounds prettd **** good

helotaxi
02-08-2004, 07:05 PM
Not recommended for extended life professional sound systems.
Talking apples and oranges. MDF makes a nonresonant enclosure and is the best choice for an enclosure that will not be installed and left in place in the vehicle or your living room or a concert hall, etc... If you need the enclosure to be tough, you compromise the sound of the enclosure slightly for the sake of durability. You know PA systems and your PA amps and they are not treated really well. You move them around alot, tossing them in and out of the truck, sliding them across the stage, stacking stuff on top of them, it might rain slightly at an outdoor venue. An MDF enclosure would not survive long in an evironment like that. That is why you know marine plywood. That is what PA stuff is made out of from necessity. We are not talking PA stuff and we do know what we are talking about. You said yourself that you are a newb to car audio. I'm sure you know more about PA gear than many on here and most of them will freely admit that. Many of us know car audio as well if not better than you know PA. There is not much in the way of crossover in the way of techniques and equipment between the two. They share music, and use the same basic components, but quickly diverge from there. Listen to what we know about car audio and if we need info on PA gear, we know who to come to.

LoudCrownVic
02-27-2004, 10:43 PM
Ha ha! Well, I ended up using floor sheeting plywood anyway and cut the resonsance with some fiberglass insulation. i sounds decent (after I got rid of the resonance issue) and was decent to work with. It's some sort of engeneered lumber, sorta like thin sheets of wood glued together. It worked.

iakona808
04-22-2004, 10:26 PM
thats cool man. why use MDF? havent you heard of the saying if everyone jumped off the bridge you should too?

Wonderbread
04-22-2004, 10:49 PM
Not quite the same case. This is more like "Why use a car with round wheels? Square ones do almost the same thing."

Jim Boom
04-24-2004, 02:39 PM
hey for MDF how do you construct it together, do screws hold, or do you use glue. Cause that stuff looks as it would kinda fall apart if you used screws, I dunno what do you all use?

tobz
04-24-2004, 03:00 PM
Why bother choosing? Any solidly built enclosure should have glued joints, as well as screws, biscuits, dowels, whatever tickles your fancy. Yes, you can use only glue if you want to, you can do anything if you want to.

Most of the people on here stating that plywood is just fine, etc, are right. Yes, plywood can make a workable enclosure. However, for those that say plywood is just fine, I'd be willing to bet that some/most of them have not seen a quality built MDF enclosure. It's like a brick house. You drop your box on the corner and it just dents. It doesn't chip, break, peel or get funky. Just a solid thump, and a dented corner - the box is still fine. MDF is solid and works well for a reason.

Try what you want, but if you shop around you can find inexpensive MDF. It's kind of a b*tch to work with, but once you get past that issue, you're home free. Just learn to make very accurate cuts, and plan it out so it fits like a glove. There should be no cracks, mismatched angles or anything. Your box should be practically air tight WITHOUT sealant/silicone/glue. That way the little bit of sealant you do use, creates a really good seal, and a really good enclosure.

That's my two cents, have fun with whatever you use.

T.J.

BIG_SUPERMAN72
04-24-2004, 03:02 PM
MDF is strong as hell my truck box i used Liquid nails to Seal it and hold together. I also used a Nail gun.
http://img8.imageshack.us/img8/2710/Pict15.JPG

http://img8.imageshack.us/img8/8742/Pict4.JPG

helotaxi
04-24-2004, 03:09 PM
Use a carbide blade on the table saw and it is really easy to work with. I dropped $25 at Home Depot for a cheap (Oldham) industrial carbide blade for my table saw and have not had any problems cutting the stuff. Carbide router bits go right through it, too.

BIG_SUPERMAN72
04-24-2004, 03:11 PM
I dunno what kinda blade i have on mine. Its a new table saw cut through it easy.

Wonderbread
04-24-2004, 07:47 PM
Glue should be enough to hold it together. I use screws as well, but they can actually be removed after the glue dries and you would see no ill effect.

BIG_SUPERMAN72
04-25-2004, 11:12 AM
I was thinking about making a box and putting it on my seat. In the middle. having it face angled into window. any ideas?

DBfan187
04-26-2004, 03:12 PM
Adding dynomat to the inside of your ported box can throw off your tuning.

pavengmike6
04-26-2004, 03:32 PM
Adding dynomat to the inside of your ported box can throw off your tuning.

Are you saying dynomat, or any sound damp material?