3/4" birch on sale at home depot

[DidUHearThat? 10+ year member]

I wonder if there is someone out there that is half way through their box going hmmmm.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Better half way than all the way.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[DidUHearThat? 10+ year member]

so is it really that much lighter?

We go thru this all the time here. Guys buy the "birch ply" and think it's the right stuff. They even argue that it's stronger and lighter! Those are not the qualities a sub box needs. Density is what is required.

Just try picking them up in the store. Compare equal sized sheets. 1" x 4' x8 of the "birch ply" then try picking up the same thickness/size MDF. Which one weighs significantly more? The reason is density.

 

[hzsogood 5,000+ posts]

this reminds me of a thread a while back where some dipshit thought building his box out of 2- 1/2" pieces of osb glued together because the 2 pieces were thicker than the 3/4" MDF //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[power-fanatic07 5,000+ posts]

hmm

 

[SPLluminator 10+ year member]

Yup its 22 here. But i got mdf for 13.31 including tax so ill stick with that.

 

[audioholic 5,000+ posts]

DidUhearthat is correct, Home Depot does not sell the good birch plywood.

 

[Mike465 10+ year member]

Don't know if it's a nationwide thing or not but at my home depot, 3/4" birch plywood 4x8 sheets are $20 a piece. Usually over 40 here

If thats the case I stock on some.

 

[DidUHearThat? 10+ year member]

If thats the case I stock on some.

Fail.//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[TNTR70 10+ year member]

tru pan ultra lite for the ftmw! ....like mdf but half the weight

 

[DidUHearThat? 10+ year member]

tru pan ultra lite for the ftmw! ....like mdf but half the weight

More fail. You want and need the density to prevent resonance. Light weight is NOT a good attribute of a sub box material. Concrete and brick also make good sub boxes, but MDF is much easier to work with. There are no wood type products that are superiour to MDF for sub boxes. Marine grade birch ply is almost as dense as MDF, but more durable (to abuse) so it is frequently used on the outside of Proaudio boxes, but the inside is still usually MDF because it is superiour. Marine grade birch ply is NOT available at Home Deopt or Lowes.

Any material that is lighter (less dense) than MDF will produce more resoance at lower volumes Than MDF. The only way to beat the weight issue is to go with a synthetic that is both denser and stronger like fiberglass, or Carbon fiber, and epoxy.

Otherwise MDF rules them all. The fact that it is also cheap, available everywhere and easy to work with means the only reason people use other products is because they don't understand the physics involved. They spend more money on inferiour products. The result is bad boxes that rattle.

 

[audioholic 5,000+ posts]

To perform correctly, the enclosure's resonant freq should dwell outside the bandwidth the system will play. So either you build it heavy as hell to resonate below 20hz, or you stiffen it (bracing) to resonate above say 120hz. Most people in car audio think they are doing the former, but they are actually doing the latter.

 

[DidUHearThat? 10+ year member]

Ironically most ply wood at Home Deopt or Lowes now contains a layer of MDF inside. Old fashion all wood grain ply is very expensive to produce and not really very good for anything.

So if you built a box with this type of ply and it worked okay, you can thank the layer of MDF in the middle. That thin layer of birch on the outside had nothing to do with it. Your box would have less rattle if you had made it out of all MDF.