Box building material.

[hispls]

(Source: http://www.huberwood.com/advantech/performance/strength)

Can somebody explain why Advantech is inferior for building a box?

[CstrokerV]

i think you need the acoustic rating and density also when looking for wood to build a box what are those 2 things on the advantech

[hispls]

i think you need the acoustic rating and density also when looking for wood to build a box what are those 2 things on the advantech

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.

[Triticum Agricolam]

Advantech is fancy OSB. I'm sure it would work fine for box building, it just may not be very pretty. I actually tried to get some to give it a try but no one in my area carries it.

I wonder what kind of plywood they were comparing it to in that graph. There are a LOT of different kinds of plywood and some are MUCH stronger/stiffer than others.

[Triticum Agricolam]

i think you need the acoustic rating and density also when looking for wood to build a box what are those 2 things on the advantech

So for box building should the density be higher or lower in your opinion?

[we_drop_bass]

Tuned for expert answers...

[CstrokerV]

i think you need the acoustic rating and density also when looking for wood to build a box what are those 2 things on the advantech

So for box building should the density be higher or lower in your opinion?

not sure i think higher.. the article might be on bcae1 not sure if i seen it there or not or the one of the cook books..

and for the acoustic measuring unit id have to look again can't find it and its time for bed for me

[hispls]

i think you need the acoustic rating and density also when looking for wood to build a box what are those 2 things on the advantech

So for box building should the density be higher or lower in your opinion?

not sure i think higher.. the article might be on bcae1 not sure if i seen it there or not or the one of the cook books..

and for the acoustic measuring unit id have to look again can't find it and its time for bed for me

While trying to gain further data I stumbled across the following posted in a forum circa 2001 by Dan Wiggins:

"From an acoustics standpoint, in order of preference:

1. void free plywood (apple ply, baltic birch, marine grade ply)

2. particle board

3. MDF

Basically, ply - especially void free - is the preferred material. Not only does it have the highest stiffness of the three, it also has the most internal losses, meaning best acoustic dissipation.

Particle board is second, primarily because of its higher internal losses than MDF. Stiffness between particle board and MDF is about equal, but particle board dissipates sound waves much better than MDF.

MDF is third because of what's given above. However, it's machinability and finish-options may give it the edge in your application.

Dan Wiggins

Adire Audio"

Bearing in mind that this may or may not apply to anything besides a full range cabinet (I'd guess that dissipating 20hz sound waves and 2000hz sine waves woud be different animals alltogether)... or of course the conventional wisdom may have changed. I've talked to someone who has tested identical boxes with MDF and particle board for SPL applications and the particle board loses 1 dB (after being painted with resin they become equal, the MDF gaining .2dB and the particle board gaining 1.2dB). Dan Wiggins has a pretty good resume as far as acoustic engineering though.

[Triticum Agricolam]

not sure i think higher.. the article might be on bcae1 not sure if i seen it there or not or the one of the cook books..

and for the acoustic measuring unit id have to look again can't find it and its time for bed for me

Ok, thanks for your response. The reason I asked is my understanding is with material selection you want to do what you can to avoid panel resonances. If you have two materials with equal stiffness the denser material is going to resonate at a lower frequency than the less dense material does. Since we are mostly building subwoofer enclosures I believe the best thing to do is push the panel resonances up above the frequency range at which subwoofers are played. For this reason I think a lighter, but stiff, material is best. Good bracing also will raise the panel resonance frequencies. Now if were were building speaker enclosures that played the full range of frequencies material selection might be different.

I generally use 3/4" 7-ply Arauco plywood for the subwoofer boxes I build. Sometimes I use MDF depending on the type of finish I will be using. For full range enclosures I prefer baltic birch plywood, or MDF.

[hispls]

not sure i think higher.. the article might be on bcae1 not sure if i seen it there or not or the one of the cook books..

and for the acoustic measuring unit id have to look again can't find it and its time for bed for me

Ok, thanks for your response. The reason I asked is my understanding is with material selection you want to do what you can to avoid panel resonances. If you have two materials with equal stiffness the denser material is going to resonate at a lower frequency than the less dense material does. Since we are mostly building subwoofer enclosures I believe the best thing to do is push the panel resonances up above the frequency range at which subwoofers are played. For this reason I think a lighter, but stiff, material is best. Good bracing also will raise the panel resonance frequencies. Now if were were building speaker enclosures that played the full range of frequencies material selection might be different.

I generally use 3/4" 7-ply Arauco plywood for the subwoofer boxes I build. Sometimes I use MDF depending on the type of finish I will be using. For full range enclosures I prefer baltic birch plywood, or MDF.

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.