What Wood Type?

[montanhasan]

I am planning to produce an acoustic box model, I would like to know your opinion about which type of wood is best for this type of box

 

[lovinthehd]

Usual materials would be mdf or void free plywood....

 

[speakerman39]

I would use 3/4" MDF due ti its consistency. If the OP opts for plywood, then I would use Birch plywood. Or, the OP could just go all out and go w/Bamboo. However, Bamboo is much more expensive. It is my understanding that Bamboo is a plant. Find that amazing.


Cheers,

Phil

 

[lovinthehd]

I've got some speakers made of bamboo (Ascend Sierra1s), but I've not looked into sourcing that for a speaker build....wonder if its readily available? I prefer using plywood over mdf due to weight and the sawdust aspects....

 

[Matthew J Poes]

Bamboo is REALLY expensive. If you buy it in bulk, it isn't so bad, but as a direct consumer, its many times more expensive than anything else.

There really is a bit of science to what is the right box material, and it comes back to what is the job of that specific enclosure.

If it is for a full range speaker, the best enclosures are usually massive and well damped. This makes MDF with CLD walls an idea solution. It helps stop sound from transmitting out of the box panels or adding distortion. MDF is better damped than plywood, so in general, is a better material for that kind of speaker.

Subwoofers or boxes primarily used for low frequencies will find mass and damping a detriment, not an aid. Instead, you want rigid. This makes plywood a far better material as it is much more rigid than MDF. Damping is of little to no value at very low frequencies, though I would argue that Damping could have benefit in some special circumstances.

That box looks like a subwoofer box? If so, I would use void free plywood like Birch.

 

[speakerman39]

Last time I checked, Bamboo was like $500 for a 4' X 8' sheet. Have no idea how much if bought in bulk. Find it interesting that Bamboo is a plant. I am sure Dave Fabrikant could explain more. Supposedly, Bamboo has several advantages over MDF. Some people prefer to use HDF as opposed to MDF. Interesting times.


Cheers,

Phil

 

[lovinthehd]

Last time I checked, Bamboo was like $500 for a 4' X 8" sheet. Have no idea how much if bought in bulk. Find it interesting that Bamboo is a plant. I am sure Dave Fabrikant could explain more. Supposedly, Bamboo has several advantages over MDF. Some people prefer to use HDF as opposed to MDF. Interesting times.


Cheers,

Phil

Well, for that matter a tree is a plant, too $500/sheet is pretty damn expensive!

 

[shadyJ]

Last time I checked, Bamboo was like $500 for a 4' X 8" sheet. Have no idea how much if bought in bulk. Find it interesting that Bamboo is a plant. I am sure Dave Fabrikant could explain more. Supposedly, Bamboo has several advantages over MDF. Some people prefer to use HDF as opposed to MDF. Interesting times.


Cheers,

Phil

Stiffer is not always better. MDF is good because it is well damped and will not ring as badly as a very stiff material and is also not extremely heavy or expensive.

 

[lovinthehd]

Bamboo is REALLY expensive. If you buy it in bulk, it isn't so bad, but as a direct consumer, its many times more expensive than anything else.

There really is a bit of science to what is the right box material, and it comes back to what is the job of that specific enclosure.

If it is for a full range speaker, the best enclosures are usually massive and well damped. This makes MDF with CLD walls an idea solution. It helps stop sound from transmitting out of the box panels or adding distortion. MDF is better damped than plywood, so in general, is a better material for that kind of speaker.

Subwoofers or boxes primarily used for low frequencies will find mass and damping a detriment, not an aid. Instead, you want rigid. This makes plywood a far better material as it is much more rigid than MDF. Damping is of little to no value at very low frequencies, though I would argue that Damping could have benefit in some special circumstances.

That box looks like a subwoofer box? If so, I would use void free plywood like Birch.

What does CLD stand for?

 

[speakerman39]

I forgot to mention that the Bamboo has to be specially ordered. IIRC, that is what my local Lowe's told me. It actually was a bit over $500 for a single 4' X 8' sheet. I even checked to see if I could get it cheaper via the shop. Nope, not one bit cheaper. I have no idea what is best to use. Just have always been told to use 3/4" MDF and be done with it. As mentioned up above Birch Plywood is useful for building sub enclosures. My boss always made us use the MDF due to its consistency and of course price.

Cheers,

Phil

 

[speakerman39]

Stiffer is not always better.

Sure wish that is true with ummmm well you know..................LOL!!!! Sorry Shady, but I just couldn't resist. I am rotflmao.


Cheers,

Phil

 

[KEW]

What does CLD stand for?

You took the letters out from under my fingers!

 

[speakerman39]

Just can't stop laughing. This made my day. Thanks Shady! Alex, is going to have a field day with this!


Cheers,

Phil

 

[speakerman39]

Hey Shady, comments like that is going to put Viagara out of business......LOL!!!!! They are scared now!


Cheers,

Phil

 

[Verdinut]

For a full range speaker enclosure, good quality MDF is about the best material as it is well damped. But for a subwoofer box, the stiffer Baltic birch plywood is superior because its higher resonant frequency is outside the usual sub operating frequencies. This material is sturdier than the MDF and also slightly lighter.

 

[Matthew J Poes]

Stiffer is not always better. MDF is good because it is well damped and will not ring as badly as a very stiff material and is also not extremely heavy or expensive.

James we have been over this Mr! Stiffer is better for LF's and damping is of little to no consequence. Damping and mass matters only above the resonance frequency of the wall of the box. It just depends on the application. Subwoofer boxes should not be massive, floppy, and well damped. They should be stiff. Damping doesn't matter. Mass matters very little.

 

[Matthew J Poes]

You took the letters out from under my fingers!

What Constrained Layer Damping isn't a household phrase to everyone else?

CLD is Constrained layer damping and is the most effective means of damping large panels. To equal the damping property of a CLD panel, a single side damped panel would need damping about half the thickness of the panel itself. Very difficult and expensive.

For totally unrelated reasons, I'm trying to figure out the change in stiffness caused by CLD. So two identical panels sandwiched together rigidly is 8 times stiffer than the single sheet. But CLD isn't a rigid coupling, so it shouldn't be 8 times stiffer. Trying to look at the mathematical formula for stiffness to figure out how this matters.

 

[Matthew J Poes]

Well, for that matter a tree is a plant, too $500/sheet is pretty damn expensive!

I think what was meant is that it's a reed or type of grass, so it grows substantially faster and with less resources than does a pine tree. MDF is made from sawdust, basically, of uniform size. Any tree takes more to grow than Bamboo, but MDF remains far cheaper (and in some ways, is a better product for the environment) than Bamboo because its made from a byproduct of the existing lumber industry that would otherwise go to waste, or in some case, burned. Utilizing a new material to make a product that already could be made from the byproduct of an existing material that isn't going anywhere is never going to be better for the environment. Today, a lot of MDF uses binders that are green in nature and not as harmful as they once were, and Bamboo needs the exact same kinds of binders for its production.

What we need is Bamboo studs. Once they start making Bamboo engineered studs, maybe we could see a shift in the lumber industry that is actually better for the environment (though I'm sure our lust for building would lead to mass deforestation and replacement with bamboo genetically engineered to grow in a variety of climates).

 

[Matthew J Poes]

I forgot to mention that the Bamboo has to be specially ordered. IIRC, that is what my local Lowe's told me. It actually was a bit over $500 for a single 4' X 8' sheet. I even checked to see if I could get it cheaper via the shop. Nope, not one bit cheaper. I have no idea what is best to use. Just have always been told to use 3/4" MDF and be done with it. As mentioned up above Birch Plywood is useful for building sub enclosures. My boss always made us use the MDF due to its consistency and of course price.

Cheers,

Phil

Around here we have a few specialty lumber yards that carry Bamboo by the sheet in stock. I can get it for less than $500 but not substantially so. I believe $350 last time I checked. But....$350 vs $50 is a no contest.

 

[lovinthehd]

I think what was meant is that it's a reed or type of grass, so it grows substantially faster and with less resources than does a pine tree. MDF is made from sawdust, basically, of uniform size. Any tree takes more to grow than Bamboo, but MDF remains far cheaper (and in some ways, is a better product for the environment) than Bamboo because its made from a byproduct of the existing lumber industry that would otherwise go to waste, or in some case, burned. Utilizing a new material to make a product that already could be made from the byproduct of an existing material that isn't going anywhere is never going to be better for the environment. Today, a lot of MDF uses binders that are green in nature and not as harmful as they once were, and Bamboo needs the exact same kinds of binders for its production.

What we need is Bamboo studs. Once they start making Bamboo engineered studs, maybe we could see a shift in the lumber industry that is actually better for the environment (though I'm sure our lust for building would lead to mass deforestation and replacement with bamboo genetically engineered to grow in a variety of climates).

LOL tell me about how well bamboo grows, I have a stand of bamboo in my yard (as well as pine trees).