3 channel sound

At Axpona Chicago I heard the comparison of stereo vs. 3 channel (Oscar Peterson and Nat King Cole's selections) through Mytek Sony Pass 5 channel dsd system. I was stunned with the change in focus of the image. Not 5 channel nonsense where music comes from 5 speakers (sorry Dire Straits) just 3 channel.

My question is besides VAS Audio, who offers a 3 channel preamp/processor? Only other one I know of is old H-K that the VAS is based on.

Has anyone ever heard the TriSound processor that James B. had released shortly before his death?