Altec's claim to fame was their VOT speaker systems, aimed at auditorium use. We had several such units in our psychoacoutics lab, and I had one at home for a time. IIRC, the HF sectorial horn came in 2 sizes with 2 different drivers, one for 500 Hz and a smaller unit for 800 Hz crossover. For home use, if you want vintage horn I'd look to JBL or Klipsh. You should definitely listen first, because horns are not kind to all sounds, especially voices, but they do project like crazy and will do a fantastic job with the horns in Aida.
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