# Best Wood To Make A Sound Quality Dual Subwoofer Box



## coomaster1

Hi, I was wondering what is the best wood to make a dual woofer subwoofer box.I was told by most high end home speaker manufactures that the reason they use medium density fiberboard for their high end sound quality speakers is because it is the best for SQ.When I contact the makers of custom subwoofer boxes around my area,They seem to want to make the box out of harder marine birch wood.They say the reason for that is ,so that the box has no flex.,and also he says it is so that the wood doesn't pick up moisture in the spring and winter months here in Canada.Is marine birch top notch wood to get top notch sound quality from your sound quality subwoofers.Who is right ,or are they both misleading me.I would love to hear from everyone who have many years of experience building sound quality speaker cabinets or car audio sub boxes to get the maximum sound quality out of the subwoofers .Thanks


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## rc10mike

Walnut


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## Catman

MDF ...because it is stable and FLAT. Or solid core birch (cabinet grade) plywood. I'd like to call "BS" on the mahogany. I've never seen it done. Mahogany is expensive. ANY solid wood will have a resonance and not be stable. It will warp and split in most cases.

>^..^<


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## minbari

MDF is cheap and it does the job 90% as well as any other. if you want the best, then go with some more expensive woods.


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## cubdenno

If you look on the diy subwoofer forums like HTS and AVS, you will see that good multiply plywood is the material of choice. Sonically even less quality less ply wood would pretty much be indestinguishable. As long as it doesn't flex, is properly braced and sealed/glued well... You will be fine.

Hell one of the great home theater horn designs for a 15" woofer uses 1/2" plywood. And that thing is amazing.


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## Se7en

+1 for Baltic Birch. Walnut, is probably the end all, but Birch is my preference to mdf.


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## perfectcircle

I use birch instead of mdf just for being lighter and way less mess then mdf. need a good blade to cut birch though. splinters a little easy.


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## Lymen

If MDF isn't tickling your fancy Baltic Birch Ply, wood be great (pun intended)

Lymen


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## nick650

Sitka spruce is the best or oak


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## [email protected]

I like to use particle board, I find it gives a nice sound in the end.


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## Niebur3

Concrete....At least you will know there is no flex!

(you guys remember that car in Car Audio and Electronics from the 94-95 range that had the concrete sub box, right???)


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## coomaster1

Hi, I just wanted to clarify that the box maker said he likes to use marine birch over Mdf so it doesn,t pick up moisture in the spring and winter months here in canada. as well as he said for the lack of flex the wood has.Is the lack of flex from the box the most important part of the sub box build for sound quality or does that really matter at all and I should solely concentrate on the type of wood. Is this an accepable answer to making a sound quality box from the sub box maker.If it helps the box I am trying to make is for two 12 inch SQ subwoofers,In a sealed enclosure.which require 2.1 cubic feet per subwoofer with either acoustic fiberglass or dacron batting.with the woofers off center to minimize standing waves.When making the box with the woofer off center to avoid standing waves ,How do I know how much off center to make it.I have never had to do that before.Do I make it off center to the left ,right,up,or down.This will be a dual seal subwoofer box so I would like to know how to off ceter each woofer to each other since they will be in the same box.Also is there a better choice for sound quality when picking either the accoustic fiberglass or the dacron batting. Thanks for all you fast responses and expertise adive to my questions.


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## asawendo

Niebur3 said:


> Concrete....At least you will know there is no flex!
> 
> (you guys remember that car in Car Audio and Electronics from the 94-95 range that had the concrete sub box, right???)


I remember that... very sick. Oh I miss that good old days...


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## Patrick Bateman

coomaster1 said:


> Hi, I was wondering what is the best wood to make a dual woofer subwoofer box.I was told by most high end home speaker manufactures that the reason they use medium density fiberboard for their high end sound quality speakers is because it is the best for SQ.When I contact the makers of custom subwoofer boxes around my area,They seem to want to make the box out of harder marine birch wood.They say the reason for that is ,so that the box has no flex.,and also he says it is so that the wood doesn't pick up moisture in the spring and winter months here in Canada.Is marine birch top notch wood to get top notch sound quality from your sound quality subwoofers.Who is right ,or are they both misleading me.I would love to hear from everyone who have many years of experience building sound quality speaker cabinets or car audio sub boxes to get the maximum sound quality out of the subwoofers .Thanks


I stopped using MDF and particleboard for the most part. I'm in the Pacific Northwest. MDF isn't terrible by any means, but plywood is lighter, stiffer, and resists moisture better.

While this doesn't apply to your case, if anyone out there is building a small enclosure or baffle, go to the local kitchen store and buy yourself a bamboo cutting board. Bamboo is stronger and stiffer than both plywood *and* MDF.

Also, as far as SQ goes, a well-braced enclosure will make a much larger difference to SQ than the type of wood that you opt for. (IE, a well braced particleboard enclousure will outperform a poorly braced plywood enclosure.)


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## rayheatfan

Baltic Birch gets my vote.


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## stills

Niebur3 said:


> Concrete....At least you will know there is no flex!
> 
> (you guys remember that car in Car Audio and Electronics from the 94-95 range that had the concrete sub box, right???)




a thunderbird or cougar iirc






whatever's on sale gets my vote


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## Niebur3

^^^^ I think that was right!


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## SSSnake

The end all be all sub enclosure material is WITHOUT a doubt teak.


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## dimibo

We are using this type of wood:


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## Catman

dimibo said:


> We are using this type of wood:
> View attachment 34478


What is the center layer?

>^..^<


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## coomaster1

It sounds like the main issue in building a sound quality box after reading all your replies is to make sure the box is heavily braced so it can't flex in or out when the subwoofers are playing.It seems no one has addressed the issue of where in the box, and how much acoustic fiberglass or dacron batting to fill the box with when making a sealed subwoofer box.Answering this question will be greatly appreciated.Thanks.


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## SSSnake

For a sub box the batting is not very critical ( wavelengths are too long for standing waves and the cones are typically thick and heavy). My suggestion would be fiberglass insulation on all surfaces. IMO bracing is much more important.


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## coomaster1

Thanks I think that spells it out very clearly for me.Easy work for all you diyma SQ experts. Thanks again.


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## dave94559

MDF is fine if the box is ported. It does not have to be sealed perfectly as well if ported. Size matters and look on the spec sheet for the best sealed or ported volume requirement. MDF is easy to work with too.


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## bippu

I've always used MDF, does the job well


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## 1edgekilla

mdf is **** to work with... not to mention the dust from it is not healthy.

hands down marine grade baltic birch... same ply the majority of your sealed professional studio quality guitar cabs are made from.


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## dimibo

Catman said:


> What is the center layer?
> 
> >^..^<


this is made of poplar wood and in the center is cork or rubber-cork membrane


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## Patrick Bateman

dave94559 said:


> MDF is fine if the box is ported. It does not have to be sealed perfectly as well if ported. Size matters and look on the spec sheet for the best sealed or ported volume requirement. MDF is easy to work with too.


You've got it completely backwards. In a sealed box, small leaks aren't the end of the world, because small leaks are very inefficient radiators. (IE, if a sealed box leaks a little, the volume of air is so small in comparison to the volume of air moved by the woofer cone, the leak basically doesn't change the SPL level.)

In fact, small leaks in a sealed box can be used to improve the impedance curve, and this can improve the damping on the woofer. Scan Speak and Dynaudio have loudspeakers that do this:










But a ported box MUST be absolutely airtight. This seems non-intuitive - if there's a giant hole in the box, *why would a few leaks matter?* The reason is that the port is tuned to a very specific frequency. *If the box has leaks, the tuning is screwed up.* To be specific, the port becomes inefficient, and the tuning frequency changes. *You can see this in an impedance plot.*

And this isn't a small difference - it can measurably alter the frequency response of your sub, AND lower your efficiency.

I hope I don't sound too severe - I've been building sub boxes for almost twenty years, and it was only in the last few years that I discovered how easy it is to screw up a loudspeaker port. *Loudspeaker ports are very very finicky, particularly when the box size is small.*


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## Patrick Bateman

dimibo said:


> We are using this type of wood:
> View attachment 34478


That is the slickest Constrained Layer Damping implementation I've ever seen


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## coomaster1

Patrick Bateman said:


> You've got it completely backwards. In a sealed box, small leaks aren't the end of the world, because small leaks are very inefficient radiators. (IE, if a sealed box leaks a little, the volume of air is so small in comparison to the volume of air moved by the woofer cone, the leak basically doesn't change the SPL level.)
> 
> In fact, small leaks in a sealed box can be used to improve the impedance curve, and this can improve the damping on the woofer. Scan Speak and Dynaudio have loudspeakers that do this:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> But a ported box MUST be absolutely airtight. This seems non-intuitive - if there's a giant hole in the box, *why would a few leaks matter?* The reason is that the port is tuned to a very specific frequency. *If the box has leaks, the tuning is screwed up.* To be specific, the port becomes inefficient, and the tuning frequency changes. *You can see this in an impedance plot.*
> 
> And this isn't a small difference - it can measurably alter the frequency response of your sub, AND lower your efficiency.
> 
> I hope I don't sound too severe - I've been building sub boxes for almost twenty years, and it was only in the last few years that I discovered how easy it is to screw up a loudspeaker port. *Loudspeaker ports are very very finicky, particularly when the box size is small.*


You can never be too severe and detailed when describing how to buid a sealed or ported sound quality box.I think 20+ years qualifies you in saying what you know from your years of experience.I'm sure others will really appreciate the finer details as well. I know I do,And I'm the one that started the thread.Thanks again for your great input.


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