Thanks. The handwritten date on it is also recent.That’s a ferrite driver. Possibly 604-8K?
The 904-8A that I converted to 604 cones also look the same.
I’ve not heard of that company.
Great! Do you know where to find the Markwart crossover schematic for 605A?very cool! I have 605a's in 620 cabs i made from MDF. Marwart cross overs.
Love these speakers, hope you do too!
@mcheinstein Thank you. I have an 8 ohm diaphragm; I don't know whether it will work or not. Currently, I am building a 30923 midrange circuit as suggested by EarlK in post #18.

No, I have just one Altec duplex 605A.You have shown two pairs of duplexes. Do you own both?
I found a picture of an Altec 605, probably inside the original Altec 614 cabinet. The insulation is on both sides and the top, but none on the bottom. The back is open, so it can't be seen, but there probably is one.recycled denim / cotton works well. The wisdom that i saw building my boxes was put it on one of each side... so back (none on front), right (none on left), bottom (none on top).

That's a great clamp set-up! I've never seen one like it.