Quote Originally Posted by spiros54 View Post
Hi,

Thanks to both of you for your responses.

One of my friends in Stockholm has an old, smashed VOTT enclosure. He sent me a wood sample where you can actually see different types of wood in the layers (I can upload a pic later). This was from one big theater in Stockholm. I believe it is 19mm thick. But if there really was a lot of variation, then we won't worry so much about replicating it beyond the birch layer. We thought perhaps that Altec choose this wood for its acoustic characteristics... but if we are wrong, then it's easier for us

Thanks,

Spiros
In the early 80's, JBL had a line of boxes called the Cabaret series .

The series started out being made with Baltic Birch ply & then ( without fanfare ) JBL switched to a different ( cheaper ?? ) type of plywood that they claimed ( when queried ) had many superior qualities to BB ( & by coincidence wasn't readily available to the rest of us, via normal retail channels ) .

They sent out ( educational ) circulars to the distributors ( who then passed this info / propaganda onto the dealers for mass consumption ) .
These circulars included some test results with formulas , etc. / so it wasn't all just junk science .

The ( newly substituted ) plywood was a special 9 ply, Maple/Poplar mix ( with 5 Maple plies & 4 Yellow Poplar ) .

The alternation of a denser hardwood with a softer wood had some superior ( claimed ) properties ( ie; less shattering upon dropping from 12" , a slightly lighter weight, a bit better damping/sound transmission & a harder surface / though with slightly more over-all flex ) .

All in all, JBL was really proud of their innovation, though ( I believe ) the perception of industry standards had them switch back to baltic birch for their follow-up ARRAY series of boxes .

A google search for Maple/Poplar plywood, reveals that Ludwig has used this plywood mix, for decades .