Ah! Wish I still had my Lockheed 'connection'.
Hmm, no clue then other than try to match up the throat or just buy another one. Did you change your mind and will use 1" drivers?
GM
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Found!: https://audioroundtable.com/misc/Altec_AN-9.pdf
https://web.archive.org/web/20050206...ages/phase.pdf
GM
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