Bamboo Plywood?

[speakerman39]

Hello people I have a question. Which is better to use for building a sub cabinet-3/4" MDF OR 3/4" Birch Plywood? I am thinking of getting the S12 Rythmik kit. I work at a car audio shop and my installer claims that MDF is better because of the gluing process. Thus, according to my installer MDF has fewer air leakes as opposed to plywood. Is he correct? I priced 3/4" MDF for about $22 for a 4' X 8' sheet. The birch plywood was $40 for the same size. What really surprised me was pricing bamboo. A 4' X 8' sheet in bamboo was over $200!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I am like WTF!!!!!!!!!!!! I priced the bamboo with an on-line retailer as I have not been able to find it locally. So, what is the best material to use in constructing this cabinet? Lastly, is bamboo really that much better than say birch plywood? Please share your comments with us. Have a great day.

 

[Johnd]

Particle board is the densest by far, making it the best. That being said, I think you'll be fine with plywood (7 ply or better). Good joinery, glue and bracing are all more important than the density of these materials.

 

[stratman]

I'd go with the MDF, it cuts better (especially if you're going to veneer later) it comes in low, medium and high densities. It cuts without chipping and gives you great edges, it doesn't resonate like plywood so it's acoustically "dead" compared to plywood, I soaked a piece of 3/4" MDF for 24 hours completely submerged in water it swelled as much as a piece of plywood, roughly a sixteenth of an inch. Plus if you're going to veneer, nothing produces a more stable and flat substrate than MDF, just to give you an idea all those beautiful, ultra-expensive modern Italian furniture is made with an MDF core.

If moisture is a problem: make sure your MDF is manufactured with water resistant glue.

 

[WmAx]

From a resonances standpoint, hardwood high grade plywood has been shown to be marginally better than MDF in a vibrational analysis study that I read, resulting in lowered amplitude resonances as the result of increased stiffness. However, with a subwoofer, it does not really matter; you should be operating the subwoofer in a band that is well below the primary resonances of the cabinet, assuming at least moderate bracing is used. Besides, if one is going for virtual 'acoustically dead', then I would not choose any standard construction method. A much more involved process will be required to actually achieve a practically silent cabinet for full range use.

As for ease of use; I find that plywood is much easier to work with in all respects. I have had no problems veneering. The normal sawdust (as compared to that horrible stuff MDF produces) is also a relief.

-Chris

 

[darien87]

Particle board is the densest by far, making it the best. That being said, I think you'll be fine with plywood (7 ply or better). Good joinery, glue and bracing are all more important than the density of these materials.

Particle board and MDF are not the same thing.

 

[stratman]

From a resonances standpoint, hardwood high grade plywood has been shown to be marginally better than MDF in a vibrational analysis study that I read, resulting in lowered amplitude resonances as the result of increased stiffness. However, with a subwoofer, it does not really matter; you should be operating the subwoofer in a band that is well below the primary resonances of the cabinet, assuming at least moderate bracing is used. Besides, if one is going for virtual 'acoustically dead', then I would not choose any standard construction method. A much more involved process will be required to actually achieve a practically silent cabinet for full range use.

As for ease of use; I find that plywood is much easier to work with in all respects. I have had no problems veneering. The normal sawdust (as compared to that horrible stuff MDF produces) is also a relief.

-Chris

Hey Chris,

I've found that beginners usually get better results when using MDF than plywood. Also it's cheaper, so mistakes don't hurt as much.

 

[Johnd]

Particle board and MDF are not the same thing.

I know. But thanks for the heads up darien.

I built my first staircase (exterior) in 1981...in a northern climate...and it is still in use today (and quite strong).

The question was... and I will quote:
"So, what is the best material to use in constructing this cabinet?"
Thus my answer for the most dense of sheet goods used in construction of cabinets. As far as joinery, particle board sucks...one needs plenty of glue and bracing. So, I think my answer was right on point. Thanks nevertheless, as my abbreviated answer was apparently not complete enough.

 

[annunaki]

If one uses plywood it must be a "void free" plywood. Any voids in plywood will most likely result in unwanted resonance, not to mention weaken the particular panel.

For a first enclosure, I would reccommend a 3/4" MDF. It is easy to work with, however, the dust can be a pain as Chris mentioned.

Void free plywood such as Birch allows for a lighter, slightly stiffer enclosure. The cost is what really does it for me. Using a bit more bracing you can have an enclose that is as strong or stronger than plywood at half the cost. Assuming one can deal with the extra weight, MDF is the material of choice. Bracing and adhesives are very important regardless of which material is used.

 

[darien87]

I know. But thanks for the heads up darien.

I built my first staircase (exterior) in 1981...in a northern climate...and it is still in use today (and quite strong).

The question was... and I will quote:
"So, what is the best material to use in constructing this cabinet?"
Thus my answer for the most dense of sheet goods used in construction of cabinets. As far as joinery, particle board sucks...one needs plenty of glue and bracing. So, I think my answer was right on point. Thanks nevertheless, as my abbreviated answer was apparently not complete enough.

No problem John. The only reason I know there's a difference is I made the same mistake when I was building my Rythmik sub. I kept asking for particle board when I really needed MDF.

 

[Johnd]

No problem John. The only reason I know there's a difference is I made the same mistake when I was building my Rythmik sub. I kept asking for particle board when I really needed MDF.

Actually, most lumberyards classify them in the same category. Curiously, most plants that maufacture mdf do not.

Either way, I've cut/installed/dadoed/glued/screwed and fastened literally thousands of sheets of the stuff. I used 42 sheets of 3/4" Black Walnut MDF in my theater for the panelled walls. It's a beautiful product, and easy to tool, it's just hell on blades and bits, and heavy as sin.

 

[speakerman39]

Particle board is the densest by far, making it the best. That being said, I think you'll be fine with plywood (7 ply or better). Good joinery, glue and bracing are all more important than the density of these materials.

Hi John thanks for posting. The info is quite helpful.

 

[speakerman39]

I'd go with the MDF, it cuts better (especially if you're going to veneer later) it comes in low, medium and high densities. It cuts without chipping and gives you great edges, it doesn't resonate like plywood so it's acoustically "dead" compared to plywood, I soaked a piece of 3/4" MDF for 24 hours completely submerged in water it swelled as much as a piece of plywood, roughly a sixteenth of an inch. Plus if you're going to veneer, nothing produces a more stable and flat substrate than MDF, just to give you an idea all those beautiful, ultra-expensive modern Italian furniture is made with an MDF core.

If moisture is a problem: make sure your MDF is manufactured with water resistant glue.

Hmmmmmmm......................interesting. Thanks for posting and I will keep this in mind.

 

[speakerman39]

From a resonances standpoint, hardwood high grade plywood has been shown to be marginally better than MDF in a vibrational analysis study that I read, resulting in lowered amplitude resonances as the result of increased stiffness. However, with a subwoofer, it does not really matter; you should be operating the subwoofer in a band that is well below the primary resonances of the cabinet, assuming at least moderate bracing is used. Besides, if one is going for virtual 'acoustically dead', then I would not choose any standard construction method. A much more involved process will be required to actually achieve a practically silent cabinet for full range use.

As for ease of use; I find that plywood is much easier to work with in all respects. I have had no problems veneering. The normal sawdust (as compared to that horrible stuff MDF produces) is also a relief.

-Chris

Hey Chris thanks for posting. Points well taken as I know you know your stuff.

 

[speakerman39]

Hey Chris,

I've found that beginners usually get better results when using MDF than plywood. Also it's cheaper, so mistakes don't hurt as much.

Very good point there.............as I make lots of mistakes.

 

[speakerman39]

If one uses plywood it must be a "void free" plywood. Any voids in plywood will most likely result in unwanted resonance, not to mention weaken the particular panel.

For a first enclosure, I would reccommend a 3/4" MDF. It is easy to work with, however, the dust can be a pain as Chris mentioned.

Void free plywood such as Birch allows for a lighter, slightly stiffer enclosure. The cost is what really does it for me. Using a bit more bracing you can have an enclose that is as strong or stronger than plywood at half the cost. Assuming one can deal with the extra weight, MDF is the material of choice. Bracing and adhesives are very important regardless of which material is used.

So, how much better performance would the birch give me vs. MDF????? Or, how about using 3/4" bamboo-would it really give me much better performance?

 

[speakerman39]

Actually, most lumberyards classify them in the same category. Curiously, most plants that maufacture mdf do not.

Either way, I've cut/installed/dadoed/glued/screwed and fastened literally thousands of sheets of the stuff. I used 42 sheets of 3/4" Black Walnut MDF in my theater for the panelled walls. It's a beautiful product, and easy to tool, it's just hell on blades and bits, and heavy as sin.

Hey John would the black walnut be heavier than oak plywood? Would oak be a better choice over say birch?

 

[jaxvon]

So, how much better performance would the birch give me vs. MDF????? Or, how about using 3/4" bamboo-would it really give me much better performance?

Nope, just select what will work best for your needs. As discussed in the thread, it really doesn't matter, just select the sheeting that fits your budget and that you know you can (or think you can) work with best. As for performance, just brace the enclosure properly to ensure you raise the panel resonance above the passband.

 

[WmAx]

So, how much better performance would the birch give me vs. MDF????? Or, how about using 3/4" bamboo-would it really give me much better performance?

For a subwoofer, it simply does not matter. Decent bracing (nothing special) of any of these materials will result in no audible panel colorations with a subwoofer. A full range speaker is far more difficult for which to build a silent cabinet.

-Chris

 

[annunaki]

So, how much better performance would the birch give me vs. MDF????? Or, how about using 3/4" bamboo-would it really give me much better performance?

Probably absolutely none that you would hear. With proper bracing, it would be very minuscule in terms of measurement as well.

 

[speakerman39]

Nope, just select what will work best for your needs. As discussed in the thread, it really doesn't matter, just select the sheeting that fits your budget and that you know you can (or think you can) work with best. As for performance, just brace the enclosure properly to ensure you raise the panel resonance above the passband.

Well, it looks like it will be MDF then. Thanks for posting.