I read through the DIY subwoofer enclosure information. It says MDF or Birch- heavy and expensive. Can I make my subwoofer enclosure out of pine instead? If not, why? Pine is lighter and cheaper. Will the subwoofer sound equally as good in a pine box as in a MDF box? What kind of sound problems will I have with my woofer in a pine box, if any?

I really want to buy a pre-made box at Circuit City, but my husband really wants to build one. Will it be just as good hand built, out of pine, as one I can buy pre-built?

Thanks,
Heather

MDF and pressed cardboard do not flex as well as wood, and do not resonate as well. This makes a box solid for better sound. Besides a wooden box will just crack from road vibrations, heat, cold, moisture and all the thumping your sub is going to make.
If you don't want MDF or plywood, use fiberglass.
Oh yeah, to make sure your subwoofer sounds the best, you must find the box that fits the specs. There are online box calculators where you enter speaker data, and get the box volume. If CC has a built box that matches your calculations or the woofer manufacturer's recommended box, buy it, if not check out www.SubZoneUSA.com they make nice boxes, but they are so damn heavy...

do yourself a favor... pine is good for coffins...

mdf is acoustically superior to most inexpensive woods for subwoofer enclosures. pine and other cheap particle boards etc will absorb moisture and swell up. also some types of particle boards will let air out.

how much can you possibly save by going to pine for a small sub box? not much... go with mdf!

unless you have a full set of wood power tools, maybe it's more cost effective to buy a pre-built box for your sub(s).

netZ

No way...
Go get atleast 3/4" MDF to fabricate a subwoofer box. Pine is really soft and will flex really bad and sound quality will suffer big time. You would be surprised how enclosure design affects sound quality. Also, you want to keep the enclosure as air tight as possible and only vent to woofer recommendations. Airspace is another issue, follow the mfg airspace requirements for the sub.

All you need is 1 sheet of MDF for your enclosure. Call around and find the best price, should be around $20. Another tip, while you are at the hardware store, buy a tube of liquid nails and a package of 1.5" drywall screws to fasten all your joints.

On the DIY subwoofer enclosure document it says, "MDF or birch is the best." So I bought Birch- real wood! Yes he is building it to the specs of my subwoofer .75 cubic feet internal space. He works as a Civil Engineer and has many years of drafting experience, so the box was an easy thing for him to design.

Next question: Is there any benefit to covering the box with the fuzzy material found on pre-made boxes? Or should I just paint it?

Heather

No benefit to carpeting, just aesthetics. For an auto subwoofer I would have built from MDF due to real wood's ability to absorb moisture, humidity, etc. For a home, birch is fine, for an auto MDF is always best.

Chad

Fuzzy material = carpet

Cover it with whatever you want. That part is all for looks. :)

MDF isnt all that expensive either.. last time i bought 3/4" was 5.00 for a 4x6 (the big sheets i think thats the size at least, i had to cut it to get it in my wagon)

I am trying hard to understand the benefit of MDF. Yes MDF and Birch cost the same, so price is not a factor in my decision. MDF is wood with glue and sawdust pressed together, much like particleboard. The argument that MDF is better in humidity and moisture is false since it is also wood and will absorb moisture just as readily as any other wood. When I flex a piece of MDF it flexes way more then a piece of birch at the same thickness (3/4"), therefore the argument that MDF is superior because it flexes less is also false. I just found birch more aesthetically appealing then MDF with it dusty messy wood. Am I missing something about MDF here? I am really trying to understand it's benefit over birch.

Thanks, Heather

MDF is the way to go for the reasons previously mentioned .. mainly the higher resistance to flexing and the lower likelihood of absorbing moisture and warping that MDF has over "natural" woods.

I bought two half sheets for like $11 or something at home depot. You have come this far don't skimp now! :)

Good luck
Fej

mdf has much more glue and is pressed together at a much higher psi than normal particle board and a greater density than any other material except hdf (hard to find and very expensive) almost water resistant at least good mdf will do this when you get a good mdf box and tap on it with somthing it will sound almost like metal
most DB dragger don't carpet because it has a tendance to muffle the sound. but fo the average daily driver it doesn't matter

MDF is worlds apart from Birch plywood for all of the reasons mentioned here.

The density of MDF makes it not resonate to the woofer. This means better bass in both volume and frequency as the enclosure provides no coloration.

As for the moisture/humidity...MDF does not really absorb water like plywood does. The voids in plywood will actually act like a sponge and over time plywood will swell so much so that 3/4 in. dado cuts I have made while making book cases dont really need much more than a thin strip of glue to hold them securely as the plywood will swell and really fill the dado in for a nice tight fit. MDF does NOT do this as there are no voids in the product and the glue used to hold the product together is actually an epoxy and water resistant. But be sure to use at least 5/8 thick for an 8 or 10 and definently 3/4 for anything larger. And make sure to include adequate bracing inside the box.

As for the carpet/paint...I do whatever matches the interior.

I guess MDF is the way to go. Okay you guys convinced me:lol:
Odd the way every document on subwoofer enclosures I have found says birch or MDF, and shows no preference to either.

What about Infinity Basslink, I mean it's enclosed in plastic- light weight flimsy plastic! How acoustical could that be? We did buy it and return it thinking the sound quality was not as clear as a 10" in a sealed box, but most people here on the club love Basslink.
Just food for thought.

Heather:huh:

I've read the same things about birch that you have Heather. I don't really have the time to test it out though. MDF will not dissapoint though. The basslink is not bad. Remember that a lot of guys here are not really audiophiles though. :)

Originally posted by Heather
What about Infinity Basslink, I mean it's enclosed in plastic- light weight flimsy plastic! How acoustical could that be? We did buy it and return it thinking the sound quality was not as clear as a 10" in a sealed box, but most people here on the club love Basslink.Just food for thought.


Most people leave the stock stereo in there dash...for these people the Basslink is a great upgrade.

just go with birch plywood, you will be fine. birch is 2X llighter than mdf. mdf is has better acoustical properties, but not by much. i have a birch plywood box for a 15" dual voicecoil JL audio sub and the thing pounds! if you put some cross-bracing and reinforcing, your box will still be lighter and just as good as an MDF box.

i was faced with the same questions before, but after i spoke to a local audio installer (who's been doing this for 20 yrs.), he told me birch is a more practical option.

jason:)

Originally posted by Heather
What about Infinity Basslink, I mean it's enclosed in plastic- light weight flimsy plastic! How acoustical could that be?

it's not going to compete with a solidly built box with a great sub and a powerful amp. But, casting in plastic does allow for a pretty stiff box with low weight. Plastic lets you put more material where it's needed to maximize stiffness at a lower weight.

I wouldn't use pine, but could see an advantage to either MDF or birch plywood, depending on how much weight is a factor to you.

I went back to the store to look at MDF and man does it flex:eek: I decided to stick with my Birch plywood and just give it a good coat of paint to seal it from the moisture;)
Very satisfied with my decision. Can't wait until my husband installs my stereo and builds my box! He will do his car first, then mine, so pehaps not for a few weeks:(

Heather

You're talking about 3/4" MDF? Flexible? I'll check my sheet at home, but the stuff I was cutting my speaker spacers out was very stiff.

A full sheet of MDF does flex some under its weight, but it does weight quite a bit more than birch. My box is sealed and made of MDF. It's braced really well. I barely feel a thing with my hand on it when it's playing. :D

I have a 2x4 sheet of 3/4 that doesn't start flexing until I start putting significant weight on it with my foot while it's supported at both ends. I think it's definitely strong enough for a sub box.

If you're worried about flex, just glue a small triangle brace periodically to reinforce the glue joint.

I weigh about 200 lbs and can jump up and down, stomping as hard as I want on the box and it doesn't even know I'm there. :)

There is absolutely no way Birch is more rigid than MDF given the same thickness... the MDF is far more dense.

Sergi

yeah. mdf is more dense, but birch is much much lighter. if you got birch at the same price as an mdf (not here in illinois, birch is twice more), then go with birch.

jason

Who cares? :furious: Honestly, this is becoming stupid. :rolleyes: Either one is supposed to work great. Design and craftmanship are far more important when considering either of these two woods. :disco: Just pick whichever one you want and go build your box! :banana:

Yes either wood is supposed to be a good choice. There are benefits to both. Let's drop it. Thread closed.

Heather:o

Originally posted by JT Clark
Who cares? :furious: Honestly, this is becoming stupid. :rolleyes:

obviously some people care. I was just trying to figure out if we were talking about the same MDF, since my experiences were so different from Heather's.


and, for what it's worth, it's possible for something to be denser, but less stiff. like lead vs. aluminum. the strands in the birch are oriented and glued in sheets, so it is possible that a sheet of birch laminate could be stiffer than a MDF laminiate, where the strands aren't oriented in the plane, but are random.

I agree that both are good choices. Some people like heavier boxes that won't move around, some people like lighter boxes for weight reduction. I'm not sure which is better for moisture.

Have a good one.

Well yeah. I was trying to get people to stop fussing so much over the differences. Especially when it seemed like they were just guessing. I have an engineering degree, so I have had experience with exactly what you are talking about. :)

I asked which is better MDF or Birch to Infinity's techincal help for their Infinity subwoofer and here is their reply:
"Most people say that MDF is better, but if you read any of the speaker building books or articles they will use both materials.
Honestly there is no noticeable performance differences in the
materials, especially if they are the same thickness.
MDF cuts a little easier and will not splinter like plywood. Typically
we use MDF on our enclosures. MDF will be a slightly deader
material compared to plywood but with a small well built enclosure you will not notice the difference."

As mentioned before my me as well, with a good coat of paint to seal the wood, both materials will be equally as moisture proof.

At least I am off pine for my box, as per my original question!:lol:

Heather

Whats funny about a thread like this is if it were a SPOKEN conversation, it would have been over in about 5 minutes :lol: :banana:

I'll agree that birch ply would likely be stiffer - it's an oriented composite material instead of glued and compressed dust. It's just much easier to make a clean enclosure with MDF because the edges of cut plywood tend to be ugly and splinter, as noted above. The only acoustic risk with plywood is that the laminations are not completely sound and individual layers could either resonate OR leak. Good quality birch ply shouldn't present either of those problems; if you bought whatever was the cheapest plywood in stock, you might worry. Just use some good silicon caulk to seal up EVERY joint in that box and you WILL be pleased with its performance.

Originally posted by 0db
I'll agree that birch ply would likely be stiffer - it's an oriented composite material instead of glued and compressed dust.

Trex decking is a somewhat similar situation. real, oriented, wood is stiff enough to handle a 20' board pretty easily. Trex is much heavier, and has the added advantage of being more flexible :) A 20' piece of decking will nearly bend in half if you try to raise it up onto an elevated deck the flat side, rather than the short side.

Have fun building your box :)