Vanguard did one sampler in Dynaquad to show off that passive matrix system. It could give decent results on a QS system, but the main push for Dynaquad was creating quad from stereo. I have a copy of it. Vanguard never did CD-4, and only used QS in Japan. They backed SQ from the get-go.
Hi. jaybird100
Vanguard did dabble in CD-4 in Japan.