Box building material.

[Broke_Audio_Addict]

I've never seen the advantech at lowes.

I'm building my enclosure like a tank out of expensive 13 ply 3/4inch birch($90 a sheet, ouch) because I feel it is better suited for the task.

Double layered 3/4"birch all the way around ftw.

It also makes me laugh when you see double and triple layer baffles but the rest of the enclosure is a single layer.

How does that even make sense?

[bassman619]

Idk what advantech is..but all i know is mdf and birch are really the only 2 materials i ever see ppl use..i prefer mdf because i feel like its less porous than natural wood..

[Triticum Agricolam]

I would suggest that for subwoofer box if you have ANY panel flex you're losing output so the frequency of resonance of those panels should be irrelevant. Oh, and Lowes supposedly sells Advantech sub-flooring if anyone wants to experiment.

I agree, a properly designed and built box should not have any panel flex, but there is a difference between panel flex and panel resonance. Its extremely difficult to completely eliminate panel resonance. The best you can do it push it up or down so that its out of the bandwidth of the enclosure.

The Lowes in my area does not carry Aventech unfortunately, its seems to be a regional thing whether they have it or not.

[hispls]

I would suggest that for subwoofer box if you have ANY panel flex you're losing output so the frequency of resonance of those panels should be irrelevant. Oh, and Lowes supposedly sells Advantech sub-flooring if anyone wants to experiment.

I agree, a properly designed and built box should not have any panel flex, but there is a difference between panel flex and panel resonance. Its extremely difficult to completely eliminate panel resonance. The best you can do it push it up or down so that its out of the bandwidth of the enclosure.

The Lowes in my area does not carry Aventech unfortunately, its seems to be a regional thing whether they have it or not.

Resonance is things vibrating in sympathy. If your box is rigid it cannot resonate (or at least to any significant degree). I just looked at "where to buy" on the site and it said Lowe's? A friend of mine local said he came across some 3/4 sanded pine ply at his local home depot at 6$ a sheet.... 150$ wall build (including glue, screws, and 2X'3's). Now I'm sort of waiting to see if he can find me a deal like that. I loathe working with MDF and the weight makes it very impractical for big builds.

I've never seen the advantech at lowes.

I'm building my enclosure like a tank out of expensive 13 ply 3/4inch birch($90 a sheet, ouch) because I feel it is better suited for the task.

Double layered 3/4"birch all the way around ftw.

It also makes me laugh when you see double and triple layer baffles but the rest of the enclosure is a single layer.

How does that even make sense?

Really depends on the sub and box size IMO. a 3 cube net box for Sundown NS 12 or similar for example. You'd have 2 sheets to support the weight of mounting the sub, a sheet for flush mounting (on the baffle), but if your sides were say 18" by 12" there would be little room for flex with just a little bracing. The length of panels acts like a lever where less and less force is needed to bend the center the longer the piece is.

Idk what advantech is..but all i know is mdf and birch are really the only 2 materials i ever see ppl use..i prefer mdf because i feel like its less porous than natural wood..

A while back there was a bit of buzz around some audio forums about bamboo ply that was light and extremely rigid. It's likely that price and availability made that material a non-starter.

Advantech is a high end very rigid OSB used for sub-flooring. As far as natural wood, I'd wager that a good hardwood (rock maple, oak, cherry, mahogany) are more rigid than most manufactured woods but that sort of thing is cost prohibitive and I think prone to deforming (shrinking expanding, and warping) with age as they dry or absorb moisture out of the air.

[Broke_Audio_Addict]

I actually considered bamboo ply and then I got a price for a sheet, fuck that.

Man is it really nice looking though.

[hispls]

I actually considered bamboo ply and then I got a price for a sheet, fuck that.

Man is it really nice looking though.

http://www.renewbamboo.com/index.php/34q-bamboo-plywood/natural-fossilized-bamboo-plywood/item/29-34-inch-plywood/86-natural-fossilized-bamboo-plywood

Aw, come on, it's 250$ a sheet, but it is an 8X6 sheet. Really crazy considering how fast bamboo grows, it must be very complex to manufacture.

I'm still sort of waiting on one of the guys who told me this stuff was terrible when I used it in my wall to chime in here to explain why Advantech is a bad material for a box.

[hispls]

Bump. Sort of hoping all the guys who were telling me how wrong I was for using this to chime in here.

[Triticum Agricolam]

Bump. Sort of hoping all the guys who were telling me how wrong I was for using this to chime in here.

Who was telling you you were wrong for using OSB?

[audiofanaticz]

What units do we use to measure "acoustic rating"? If the box is rigid (not flexing), why is density important?

Density compared to ply here:

I suspect if one cared to download the PDF you could find specific measurements.

Bump. Sort of hoping all the guys who were telling me how wrong I was for using this to chime in here.

Who was telling you you were wrong for using OSB?

He is referring to Meade and I.

The advantech video shows nothing about it being compared to mdf.

Im willing to bet after drilled all those holes in the advantech to make it the same weight as a cheaper alternatives product that it would no longer support the same amount of weight as the cheaper product.

Also the video has said something Ive griped about for the longest time.

Douglas fir.

All these $35-60 per 4by8 sheets of "birch" that people call it is nothing more than cheap plywood with a Douglas fir core and a thin veneer of birch that does nothing for strength and only looks pretty.

These woods are filled with massive voids and knot holes that you typically only see while cutting into the wood if you get lucky but just because you dont see them does not mean they are not there. Hell some people even found rocks in their wood (think it was Taylor Fade that posted a picture).

But sure these woods are lighter in weight than mdf and thats due to the type of wood they are made from, Douglas fir...

Im sure if you put a piece of baltic birch next to Douglas fir it will destroy the fir, and even advantech, but again that would not be a fair comparison.

Also I dont see using information from 2001 a viable source to prove a point. 14 years ago and a lot has changed, especially in the way companies manufacture their wood to make even a better stronger product.

Comparing a higher tiered product to a cheaper or lower tiered product will never be fair.

Where is the love for TruPan? That is not your typical mdf just like advantech is not your typical osb, but yet you are trying to compare it as just that.

[hispls]

What units do we use to measure "acoustic rating"? If the box is rigid (not flexing), why is density important?

Density compared to ply here:

I suspect if one cared to download the PDF you could find specific measurements.

Bump. Sort of hoping all the guys who were telling me how wrong I was for using this to chime in here.

Who was telling you you were wrong for using OSB?

He is referring to Meade and I.

The advantech video shows nothing about it being compared to mdf.

Im willing to bet after drilled all those holes in the advantech to make it the same weight as a cheaper alternatives product that it would no longer support the same amount of weight as the cheaper product.

Also the video has said something Ive griped about for the longest time.

Douglas fir.

All these $35-60 per 4by8 sheets of "birch" that people call it is nothing more than cheap plywood with a Douglas fir core and a thin veneer of birch that does nothing for strength and only looks pretty.

These woods are filled with massive voids and knot holes that you typically only see while cutting into the wood if you get lucky but just because you dont see them does not mean they are not there. Hell some people even found rocks in their wood (think it was Taylor Fade that posted a picture).

But sure these woods are lighter in weight than mdf and thats due to the type of wood they are made from, Douglas fir...

Im sure if you put a piece of baltic birch next to Douglas fir it will destroy the fir, and even advantech, but again that would not be a fair comparison.

Also I dont see using information from 2001 a viable source to prove a point. 14 years ago and a lot has changed, especially in the way companies manufacture their wood to make even a better stronger product.

Comparing a higher tiered product to a cheaper or lower tiered product will never be fair.

Where is the love for TruPan? That is not your typical mdf just like advantech is not your typical osb, but yet you are trying to compare it as just that.

I can assure you that all the MDF I've seen isn't nearly as rigid as the Advantech subflooring. The point of the holes video wasn't to say they could cut all that out and it would still have the same strength, just illustrating your point about how much of what you see of a piece of cheaper plywood is actually empty space (voids). MDF would likely look the same since it's just paper pulp set with glue. I'd wager much of the strength and density of any of these sort of "wood" products is from the glues.

When you start talking about the pedigree filler plywood you might as well be buying bamboo ply for the price and at that point you might as well be buying a 50 gallon drum of resin and a cubic yard of chop mat. I've found that generally the plywood with a better veneer (oak, birch, maple, etc.) generally has better quality ply inside, but I'm sure that doesn't always hold true.

Now according to this: http://www.g-lumber.com/pdf/APA_Plywood_Design_Specification.pdf there's actually 2 types of Douglas Fir. One is in the same group for stiffness as rock maple, birch, and beech, the other is down with spruce and yellow poplar. The PDF also suggests that the glue between plies gives much of the strength so number of plies is certainly a good indicator of a stiffer product. Birch itself isn't terribly strong, just lightweight, so I'm not sure why it's lumped in with rock maple? Then again, there's only 4 classifications for wood species for industry purposes.

I did qualify the Wiggins quote by saying that was old and perhaps conventional wisdom has changed. That said, if you can't provide any evidence that the "technology" used to make any of these lumber products has changed I'm going to go out on a limb and guess that the MDF we get now is the same as we were buying 15 years ago. "Premium" MDF aside, of course. Is that TruPan stronger or just lighter with no formaldehyde? Have you seen or used it in person? Lighter and non cancer causing MDF sounds great to me.

I spent a bit of time looking for comparable data on MDF vs. ply, vs. Advantech, vs whatever else. The only spec sheets I found for MDF were in N M as opposed to ft lbs from the Advantech site and as opposed to trying to do the math I just posted this hoping that others would either be able to dig up some accurate material specs.

I'd really like to get to the bottom of this if anybody else can help dig up data.

OH, did you get my PM about that "high temp" coil? I have a friend that's trying to build some new subs and I'd like to test that before we pull the trigger on buying coils.