Hardwood plywood for speakers?

[Spasticteapot]

I'm making a pair of open-baffles out of hardwood plywood. It's really nice stuff - very strong, and it's got what amounts to a nice birch veneer. 25$ for a 4x8 sheet of 3/4" thick material - only $5 more than cheap plywood.

I've heard that plywood can split in speaker cabinets, though; that's why so many people instead use MDF. Could I get away with using this? What if I only used it for the front baffle and bakck of the speaker, with the sides, top, and bottom made of MDF?

[Cal Weldon]

Plywood shouldn't split.

What is the core?

[Spasticteapot]

Originally posted by Cal Weldon
Plywood shouldn't split.

What is the core?

I think it's hardwood all the way through.

I read that plywood speaker boxes had splitting problems in my book on speaker construction, but it appears to have been written in 1968 - and none of the projects in it are exactly "audiophile-grade".

[Cal Weldon]

You should be ok. The only time I can remember splitting is when I used to bang them together with big 'ol common nails and whatever plywood Dad had laying around.

That a few years ago now.

[Curmudgeon]

MDF is popular because it has good self-damping properties. Plywood is superior structurally and cosmetically, but imho requires more bracing and damping to silence it.

[FrankWW]

I've got plywood speaker cabinets that are 40 years old and they're just fine. Don't worry about it.

[Spasticteapot]

Originally posted by Curmudgeon
MDF is popular because it has good self-damping properties. Plywood is superior structurally and cosmetically, but imho requires more bracing and damping to silence it.

I'm building some horns, which were originally made with actual hardwood.

http://www.audio-resolution.com/zhorn/fr125s.html

Due to their design, they have a massive amount of internal bracing - the inside of the speaker is only 3" thick!

[Bigfootpete]

I think multiply plywood is probably better (multiple layers pre-sandwiched together - if you can get it). It is denser than MDF.

[Richard Ellis]

I think plywood is a superior material for cabinet construction, however I think the move to MDF is more of a convenience as MDF is more forgiving for "sloppy" construction.
I personally use 1" MDF, I will not use anything less thick, perhaps shoebox size enclosures I could use 3/4" and feel OK about it.
Perhaps those who have used plywood invariably use too coarse a saw to cut it with & wrongly come to the conclusion that it is an inferior material. I would feel a good quality seven or nine ply plywood would be superior given great care is used in the sizing, cutting of said plywood.
____________________________________Rick..........

[pjanda1]

$25 is far too cheap for usable ply, unless it is some incredible sale. The cheapest decent stuff I've found is $60 a sheet (baltic birch from Menards, the face veneer isn't great and it's a little warped.) Keep in mind that any internal voids might buzz, rattle or otherwise make noise. You'll know when you cut it if you've got voids or not. The edges are often better looking that the center, and some places fill the voids on the edges. Look closely. I have built cabinets out of the $35 a sheet stuff from Home Depot; I wouldn't do it again. You might get away with it on open baffles, and if it doesn't work you're not out much anyway.

Paul