In that listing or website that is trying to get it all down, so we can trace this stuff...the company ’Cambridge’ is MIA.
Cambridge came out of Cambridge Ontario and they had pretty well millions of woofers in Canadian made loudspeakers. the ’millions’ is literal.
EG, a sh-ton of Energy, PSB, Mirage, and Paradigm speakers had Cambridge woofers in them. Many other brands, as well. Cambridge did design and build to spec, likened to Tonegen.
Yet... they are now gone... and there is no history of them, at all.