Left and right channel crossover and compensation circuits wired together.
The four boxes are stacked on a small wooden table between the speakers.
Subjectively, the sound is a bit different from the Joe Roberts inspired 1st order high pass horn and full range woofer configuration DT667 had been listening to for several years.
Hearing the 811B horn operating over its full range from 800Hz up and the 414-8B functioning as a proper mid-woofer has been enlightening.
DT667's SE 7C5 "LOW DCR" stereo breadboard amp is currently powering the Altec horn system to great effect.
DT667 11/18/2022