Subwoofer enclosure material - MDF versus Plywood

[jonblack 0]

Hey guys

I remember years back, when we wanted to build a "premium" subwoofer enclosure we would use birch plywood rather than particale board. Back in the late 1980s and early 1990s we mostly used particle board, not MDF, at least not at the shops I worked at. I don't know if it was because MDF wasn't widely available, or if it was more expensive, or if we just didn't know about it.

So, my question is: What are your thoughts on using birch plywood for a subwooder enclosure? How do you think the enclosure would handle flex and can you comment about its tonal qualities?

What brought this question to my mind is that MDF really is not a great material for holding fasteners (screws). If you swap your woofer out a few times the screw holes are more or less shot.

I was think of using T-nuts or some other threaded insert, and use machine screws to mount the subwoofer. That way the woofer could be removed would damaging the enclosure.

Care to brainstorm?

Thanks

jonblack

[Kawonu 0]

I've always used MDF until this last build and used 1" birch. I reinforced with 3/4" all thread rod. I like the sound of MDF better. Also, I recommend EZ-Loc threaded inserts. Place them on the underneath side of the wood and use machine screws with socket heads and I've never had another problem. Which is good because I use aeroports and always changing out to tweak the tuning.

[SS Teacher 177]

I've read a couple of posts on birch vs. mdf and the big pros of the birch is weight savings, of course mdf is cheaper. You're spot on about the lack of longevity of the mdf and screwing and unscrewing but they make a great number of fasteners like you mentioned. Madisound and Parts Express should have everything you could ever want in the fastener department.

[///M5 2,833]

epends on the quality of the ply. Cheap ply is worse than mdf, good baltic birch ply (~$75/sheet) is better.

I like the sound of MDF better.

I'll assume by sound you mean you'd rather use it as acoustically you sure as shit aren't going to hear a difference.

[Kawonu 0]

Yes i mean acoustically. I paid $73 bucks a sheet for baltic. It is not as forgiving to work with as MDF either. But it is way lighter which is what I needed going from 1 x 15 to 2 x15s with extra amp and batteries. I'm also using spun metal flares on 10" aeros which seem to add a bit more noise than just having the PVC flared themselves. Both have pros and cons.

[///M5 2,833]

Something else changed then which of course is hard to avoid.

[Kawonu 0]

Yes and still working through troubleshooting the issue.

[Adrian_D 520]

epends on the quality of the ply. Cheap ply is worse than mdf, good baltic birch ply (~$75/sheet) is better.

I like the sound of MDF better.

I'll assume by sound you mean you'd rather use it as acoustically you sure as shit aren't going to hear a difference.

European Beech Ply is very strong and ridiculously expensive. The guy at the wood shop recommended it over Birch for strength.

[///M5 2,833]

Balt

epends on the quality of the ply. Cheap ply is worse than mdf, good baltic birch ply (~$75/sheet) is better.

I like the sound of MDF better.

I'll assume by sound you mean you'd rather use it as acoustically you sure as shit aren't going to hear a difference.

European Beech Ply is very strong and ridiculously expensive. The guy at the wood shop recommended it over Birch for strength.

Called Baltic Birch here. Love it. In fact cut some tonight

[jonblack 0]

Seems like I remember birch plywood enclosures having a different sound. Of course that was years ago and I may have been just imagining things. I wouldn't mind doing a comparison test just to see if I am remembering things right. Compare MDF or birch to a concrete speaker enclosure and I imagine one could tell the difference.

Another thing we did that we thought made boxes sound better was paint the inside of the box. Any old paint would do. Years later I told a friend about that "concept" and he thought I was crazy. He had worked at higher end shops than I had and built many nice enclosures. The next enclosure he built he painted the inside. He said the box sounded awesome and was convinced that the paint made a difference. Of course, no blind test so at that point everthing is subjective. Lots of beer was drank in those days, though, so it may have had something to do with our perception.

Anybody else heard of painting the inside of the box to improve the sound?

jonblack

[Impious 1,476]

Painting it wouldn't be any different than fiberglass resin. It's going to act as a sealant and possibly make enclosure walls a little "smoother" for air flow transfer. MIGHT be measurable on a microphone but I seriously doubt the difference would be significant enough to be audible, unless the enclosure was poorly sealed to start with.

[///M5 2,833]

In a reasonably well built enclosure there will be no audible difference between mdf or ply.

[TML_LUNCHBOX 4]

Years back a team and I built 4 identical enclosures 2 where birch and 2 where mdf. 1 of each kind had fiberglass resin rolled on with a smooth foam brush roller on the inside. For testing we used the same drivers and power in the same car in the same location inside the vehicle taped off. Power was the same clamped (va) power. Both the plain unresin enclosures had the exact same score. The resined enclosures where indecisive same score or .1db loud 

[TML_LUNCHBOX 4]

ohh and birch is much easier to work with and less mess (saw dust) and its just as strong or if not stronger then mdf

[SpeakerBoy 64]

Does plexiglass or lexan color the sound at all, if you were to do an all plexi/lexan enclosure?

Fuck the price tag, but just curious if it's a simple as make the box solid and sealed and you're good to go.

[95Honda 486]

Not if you use 1" thick material and the box isn't too big...  Price and assembly becomes prohibitive, though...

[pmureika 31]

ohh and birch is much easier to work with and less mess (saw dust) and its just as strong or if not stronger then mdf

Depends on which grade birch plywood!

[Tenacious 32]

Phenolic birch works well, plus it looks great. It can get expensive, though.

 

Appleply Maple is another alternative to baltic birch.

 

In all honesty, you're not going to notice much difference between any types of wood as long as you're not using particle board or cheap plywood with a lot of voids. The weight differences are huge, though.

[Shogen 325]

Phenolic birch works well, plus it looks great. It can get expensive, though.

Appleply Maple is another alternative to baltic birch.

In all honesty, you're not going to notice much difference between any types of wood as long as you're not using particle board or cheap plywood with a lot of voids. The weight differences are huge, though.

Curious about the weight differences.. Like full sheet (4x8)...

[EPerez 236]

I used the Home Depot 5 ply birch and I love it. It seems to be very stong and I love the weight difference from mdf. It's extremely light compared to mdf. And it's only $10 more

[frogcase2002 393]

I used the Home Depot 5 ply birch and I love it. It seems to be very stong and I love the weight difference from mdf. It's extremely light compared to mdf. And it's only $10 more

Yea iv had a lot of successful builds using the birch they have at home depot and lowes. Could be a little better quality but iv never had problems with it and it seems a good amount lighter than mdf

[Tenacious 32]

 

Phenolic birch works well, plus it looks great. It can get expensive, though.

Appleply Maple is another alternative to baltic birch.

In all honesty, you're not going to notice much difference between any types of wood as long as you're not using particle board or cheap plywood with a lot of voids. The weight differences are huge, though.

Curious about the weight differences.. Like full sheet (4x8)...

 

 

Depends on the manufacturer.. A 4'x8' sheet of MDF (3/4") is around 90 lbs and cheap "birch plywood" will weigh around 60 lbs with a good amount of variance. Some manufacturers may have MDF that weighs, for example, 80 lbs per sheet and others may have MDF that weighs 100 lbs per sheet. Cheap birch ply often has a core made from cheaper wood and has a birch veneer on it. 

 

EDIT: Baltic birch

 

According to one manufacturer's specs, a 4'x8' sheet of baltic birch that is 3/4" thick weighs 95lbs. I didn't realize it weighed about the same as MDF. We learn something new every day.

Edited March 7, 2014 by Tenacious

[95Honda 486]

In all honesty, MDF is probably the best material there is for building subwoofer enclosures.  It self demapens well and is fairly strong.

[Squity 0]

On 7/13/2012 at 12:43 PM, jonblack said:

Hey guys

I remember years back, when we wanted to build a "premium" subwoofer enclosure we would use birch plywood rather than particale board. Back in the late 1980s and early 1990s we mostly used particle board, not MDF, at least not at the shops I worked at. I don't know if it was because MDF wasn't widely available, or if it was more expensive, or if we just didn't know about it.

So, my question is: What are your thoughts on using birch plywood for a subwooder enclosure? How do you think the enclosure would handle flex and can you comment about its tonal qualities?

What brought this question to my mind is that MDF really is not a great material for holding fasteners (screws). If you swap your woofer out a few times the screw holes are more or less shot.

I was think of using T-nuts or some other threaded insert, and use machine screws to mount the subwoofer. That way the woofer could be removed would damaging the enclosure.

Care to brainstorm?

Thanks

jonblack

MDF is ideal for cutting, machining and drilling, since it does not chip easily.

On the other hand, plywood is a much more stronger material, which can be used for doors, floors, staircases and outdoor furniture. It is easier to create curved surfaces with plywood, since it bends easily.