I know the KS12024 from the Western Electric L-8 which uses the phenolic 713 driver and a 728 woofer. Pics attached.
Not many of these were installed in this country so they are difficult to hear. More show up in India and Pakistan, maybe Australia, due to Westrex penetration of those markets. WE wasn't selling theater gear here in that era due to anti-trust actions.
The 12024 sounds really good in that implementation. The throat is smaller than 1" so I couldn't try them with Altec 802s. My friend is making a 1" version which could be interesting. He likes it better than the 32s he printed, so I am intrigued.
As I constantly reiterate, almost anything is better than 511s, which are plagued by internal reflections and consequent massive high order garbage as illustrated in the waterfall plot I posted earlier.
Altec didn't make any 12" horn loaded boxes as you desire, but I have a pr of min- VOT style cabs for 12" made by a DIYer decades ago. They are nice boxes. I could be convinced to move these out since I really need some space!
The purpose of the horn in the VOT cabs is not so much to horn load the cone but rather it functions as a lens to narrow the horizontal dispersion to approximate the horizontal dispersion of the horn at crossover. The short horn loading it does provide mainly results in a small bump at 120-150hz, but my sense is that dispersion control is really what is going on with that box.
Also, the recessed woofer allows for closer time alignment of the midrange and LF sources. That right there is a good enough reason to go with the short horn.
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