Not custom amps, custom speakers for high-end stereos. His were the first I saw for home use that had the subwoofer separate from the mid/high speakers. The sub was a 2-foot cube that looked like an end table. The mid/highs were about 18 inches square and three inches deep and hung on the wall. They were as large as they were because they were packed with custom-built active crossovers, tuned to the room they were in. This was all before you could buy a tunable crossover.

For a system that you almost couldn't see the speakers unless you knew what you were looking for, it was amazing. Crystal clear even from next-door. And yes, he tested them that way.