Velocity-coupled_Infa_Bass_Speaker_and_3_D_microphone

I have the original Infa bass speaker and a 3D microphone built by Graham Holliman, I cannot find any records of professional people whom he may have had dealings with over the years, the later being his new invention. I would welcome any suggestions or feedback from any universities, research centres or museums. Graham Holliman had several articles written in the 70s in Hi Fi magazines.