Why not MDF?

[Zack Brock]

Ok, so I'm completely new to BF cabs, and I've done some searching on the forums.

Is there any real reason other than weight (which is the only negative I found by searching) to not build a BF cab out of MDF?

MDF is so cheap it is very tempting. It is also completely and perfectly straight and void free... unlike most plywoods (even good sheets of baltic birch). Is there a performance issue?

If I'm going for a permanent install, can I use MDF?

Someone please convince me with a reason other than weight...

Can it alter the sound? Does it have a different resonant frequency? Is there a problem with glueing and screwing it? Can I still finish it with Duratex or carpet without problems? Lots o' questions... but I'm probably going to build two Omni 10's, two vocal monitors, and two Tuba 24s. I've already purchased and cut the $90 worth of Sandyply to assemble the Tuba 24s. I'm trying to figure out a way to save some more cash.

Thanks!

[WB]

If I'm going for a permanent install, can I use MDF?

Yes.

but I'm probably going to build two Omni 10's, two vocal monitors, and two Tuba 24s.

I doubt these will never get moved around. Other than home theater, I wouldn't do it.

[DAVID_L_PERRY]

Weight is the only real issue (but what an issue... )
Strength of MDF panels is not great and as such you may end up going for thicker panels than the 12mm standard Ply on the outer boxes of say the titans....

The dust element makes it a bitch to work with in my opinion.

I would rather work with Birch Ply any day, but thats to stand up to road rash...

Other than that, if its an install go for it...

[Zack Brock]

Hey guys, thanks for the replies!

I guess I can try out a sheet and see how much it really weighs. Certainly cheap enough to try.

While I might move these around, it would only be for when we recarpet the room or paint the ceiling

[fender3x]

It does sound like a good candidate for MDF...but you haven't said what you are making out of it? Some BFM designs require bending the wood (DRs for example), and I don't think MDF will work well for that. For flat parts it should be fine...but wear a dust mask--especially if you are working indoors. Dave's right. It produces toxic sawdust.

[WB]

...but you haven't said what you are making out of it?

The last paragraph has that info.

[fender3x]

The last paragraph has that info.

Oops! My bad.

[Zack Brock]

It's all good fender, I miss detail in posts all the time.

By the way, we are neighbors! You are in Miami, and I'm in Jacksonville. LOL

My build list:

QTY
2 Tuba 24 - 24" wide version with two BP102s each
2 Omni 10 - 24" wide version with crossfire tweeter array
2 Full Range Wedgehorns

So I've already bought and cut up into pieces three sheets of $29 Sandeply 4x8 size. $90+ after tax, and that was just to make the two subs.

So if I can save some cash on the Omni 10 and the Wedgehorns, then nice!

[Sydney]

I made my T24 out of ply ( not BB however ) and my T18 out of MDF.
My T24 weighs 60lbs and I calculate it would weigh 75lbs if it were made out of MDF.
MDF does work similar to wood in some aspects. It can end split. it doesn't chip like plywood however. I take precautions like pre-drilling and countersinking - But I do this for plywood as well.
Duster than plywood - but all woodworking generates dust, so a mask is always necessary.
Some of the advantages as you stated are it cost and consistency. I can find a variety of MDF products with and w/o veneers in panels smaller than 4x8.
This is easier to work with than a full sheet ( for me ).
All raw surfaces of MDF should be sealed as it will wick moisture. Use any polyurethane glue and finishes.
You may find the surface of MDF too smooth - so a very light sanding will break the glaze and help sealing and finishing.
Sonic wise it is fairly inert and usually has less resonance than ply ( a well braced cabinet shouldn't have those problems regardless )
Corners and edges of MDF don't hold up as well as ply, so count on reinforcing with corners/edging etc
* If it's gonna see the road you should go with a good plywood.

[gdougherty]

Plywood would be less prone to fracture if it did get dropped. Multiple layers laminated together are more stable than MDF or solid wood.

[Marko Rooseno]

Hi guys,

So MDF may be ok for Omni, Tuba, Titan. I guess a follow up question would be would it be ok for DRxxx?

Thanks!

=M=

[David Robinson]

You ain't gonna be able to bend MDF! For the outer sides and back, maybe if it's for an installed application. I'd be more comfortable using it for rarely moved subs, but I'd shy away from it for use in top cabs.

[Marko Rooseno]

You ain't gonna be able to bend MDF!

Yes I know that much.. LOL

Was talking about more towards the the-non-bendy-bits of DRxxx..

[Tim A]

Why in the hell would anyone go to all the time and trouble to build some of the best sounding designs in the world, and then cut corners? This makes absolutely no sense. I don't care if it's for a permanent install, or because you don't have all the money right now, or if it's simply because you're a cheap-ass.

Save your money and build them the right way. You will NEVER be sorry you did that, but there may come a day when you are very sorry you used MDF.

Buy once, cry once.

[Marko Rooseno]

Just a curious question that I thought I'd ask, following up on the topic started.

I'm a firm believer that there are no stupid question to be asked, and the worst that can happen when a question is asked is to have "no" as the answer.

I do welcome all feedback, and I'd rather ask and know what-not-to-do now, than be oblivious/ignorant, spend (what is thought to be a cost saver), and be sorry later.

And in this particular case MDF is DEFINITELY not the way to go.