Well, it's not a early large format driver 511E, but it is an early 511A, though not sure whether the second set of driver mounting holes is OEM, though it wouldn't surprise me since it was marketed as a paging horn, hence the lack of flange mounting holes.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Those extra mounting holes look like the JBL small format layout.

I give his listing one "Duh!"
As the saying goes a little knowledge is dangerous...
Small Altecs were originally 3 bolt. HiFi drivers switched to two bolt for the two piece horns. This is set up for a 730A.
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Your neighbors called. They like your music.

Jim Lansing continued to use the 3 bolt after Altec switched, so yes.
Top pic is an 801- field coil just before the 802....
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Your neighbors called. They like your music.
Right, but did the early 511 come pre-drilled for it [and by association, JBL or similar drivers] since AFAIK the 511 didn't come along until at least the mid '50s, though the first I saw of it for sure [way up on a pole it's hard to tell size] was with the introduction of the 820's replacement, the Laguna system, which in retrospect was probably done to pay homage to Hilliard's then SOTA home HIFI system.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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