Help identifying 800 series drivers

[Lrover66]

I'm trying to rebuild my Altec A7 Voice of the Theater speakers out of bits and pieces that somehow have survived several moves and many years of storage in a disassembled state.

Here's what I know I have :

- two A7 cabinets with some replacement 416-8a woofers on the way.

- a pair of the 511B horns

- a pair of N809-8A crossover networks

- a pair of new in the box Altec 21545 diaphragms for the high frequency drivers (bought these over 25 years ago and never installed them).

- a pair of high frequency drivers - model unknown (look like 800 series but there are no labels or back covers) - 1" throat - with numbers 391524 on one and 391350 rubber stamped on the back surface.

- the pair of original 21545 diaphragms have broken conductors leading to the diaphragm - can these be repaired?


I think I have everything I need to assemble the speakers with the exception of the back covers with the terminal posts for the high frequency drivers - I'll contact Bill about those.

What I need help on is this - what model driver do I have and are the diaphragms I have the right impedance? I assume I need 8 ohm since everything else I have is that value.
Are these the best diaphragms for this assemblage - I'm also concerned about how the 800 Hz crossover will work with the 500 horns.

[bfish]

21545 is an 8 ohm Symbiotik 'fram. If they were the original 'frams, then your drivers are either 807-8As or 808-8As, you could tell which by the front-to-back dimension.

The broken leads can be soldered with a steady hand.

If you get new rear covers from Bill they'll have the wire terminals for the newer 'frams, but can be changed.

All-aluminum 'frams are preferable for HIFI over Symbiotiks. You might get a fair way to buying new 'frams by selling your NOS Symbiotiks on eBay... maybe.

800Hz XO on a 511 is no problem.

[Lrover66]

Thanks! - great information and very helpful.

My drivers measure 2-1/2" front to back - does that make them 808's or 807's?

The 21545 'frams have an aluminum looking dome in the center with a brownish looking flexible diaphragm connecting the dome to the mounting ring - I guess this is where the Symbiotik description comes from?

[Old Guy]

The dome is the diaphragm, technically

The brown ring is called a "surround" or "suspension". It is not the diaphragm.

Symbiotik has the brown Mylar suspension. The Hi-Fi diaphragm has an aluminum suspension, sorta crinkly looking.

The Symbiotik name comes from the use of two different materials working together.