Altec A7 VOTT speakers - source for cabinet wood?

[spiros54]

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

From my 46 years use of Altec gear, and involvement with Altec, I have no clue where you got the info. AFAIK it is 100% wrong.
Altec used different plywood at different times, but all I have ever seen is just plain old domestic fir plywood. Some cabs were 5/8", others 3/4".

Altec made factory cabs and used contractors at a couple points I know of. IMHO you are chasing a fantasy.

[Old Guy]

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

No guarantee that is a factory cabinet. In fact likely not. Many local contractors built their own. Can you imagine the cost of shipping a plywood box from California to Sweden? The factory would cheerfully sell you VOTT decals in the old days. We built dozens and badged them as VOTTs.

A plywood REAL Altec box would certainly be .75 or .625 inch, not 19mm. Almost certain that was locally built.

See added line to my first post.

[GM]

Almost certain that was locally built.

+1. Altec continued the business plan developed by W.E., so need to find out if there's a plywood local to Stockholm that was available back when the cinema opened. Here in Hotlanta, I can't recall ever seeing a VOTT cab shipped to the distributor, though of course I wasn't over there there very often. CMC Stereo OTOH ordered pallet VOTTs [unassembled]. These cabs were so cheap that they were pretty much more trouble than they were worth to tweak them for HIFI, though fine for MI apps.

GM

[spiros54]

hi guys, I will use 25mm MDF, any thought's about?
Here is a friend's VOTT

[Old Guy]

MDF may well be superior for cabinets that are not hauled around. The are low formaldehyde MDF's available...worth it for health reasons of you can find.

[spiros54]

thanks OG, I will study your post!
regards
Spiros

[Earl K]

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 .

[Old Guy]

Interesting. the Israelis were looking for a cheap way to armor vehicles. They did sheet metal/styrofoam ad infinitum layers...well really only a few layers. Anyway- metal spreads the force over a large area,foam absorbs energy, repeat as necessary. The result was made from two cheap available items and would stop sizable fragments or bullets.

Gotta wonder if the differing wood layers performs likewise.

I am not a techno geek, I just play one on TV.

[Earl K]

Yes I agree, it's all pretty interesting ( the whole constrained layer damping thing ) / just not quite interesting enough to have me search it out & use it instead of Baltic Birch .

[Old Guy]

Yes I agree, it's all pretty interesting ( the whole constrained layer damping thing ) / just not quite interesting enough to have me search it out & use it instead of Baltic Birch .

Yeah that sounds too much like work. I fish these days.