While working as chief engineer at United Western in LosAngeles, I developed the ECOPLATE reverberation device after the patent ran out on the famous EMT plate. I offered it to UREI, another of Bill Putnam's compaies, but they thought it was not suitable for their product range, so I started a Company in Chicago called Studio Technologies where we manufactured it. Now retired I have a small company called JCC & Assoc. where I sell parts for all kinds of plates. Go to platereveb.com to see the plans to build your own plate.