Unlike a piano or organ, early synthesizers, such as Moog and ARP, can generate only one note at a time. Setting multiple knobs, switches or dials to shape a particular tone and then trying to reproduce that tone means writing down all the settings and hoping to get the same results next time.
Prophet-5, which Mr. Smith designed with John Bowen and released in 1978, overcoming both defects. By controlling the functions of the synthesizer with microprocessors, it can play five notes simultaneously, allowing compatibility. (The company also made the 10-note Prophet-10.) Prophet also used a microprocessor to store settings in memory, which provided reliable yet personalized sounds, and was portable enough to be used on stage.
Mr. Smith’s small company was overwhelmed with orders; At some point, the Prophet-5 had a two-year backlog.
But Mr. Smith’s innovations went a long way. Mr. Smith explained in 2014. Other keyboard manufacturers began to incorporate microprocessors, but each company used a different, incompatible interface, a situation Mr. Smith said he considers himself “dumb.”
In 1981, Mr. Smith and Chatwood, Sequential Circuit Engineers, presented a paper at the Audio Engineering Society conference proposing “The USI or Universal Synthesizer Interface”. The point he recalls in a 2014 interview with Waveshaper Media was, “Here’s an interface. It doesn’t have to be this way, but we all need to do something together. Otherwise, he said, “this market is not going anywhere.”
Four Japanese companies – Roland, Korg, Yamaha and Kawai – were willing to cooperate with the sequential circuit on a shared scale, and Mr. Smith and Mr. Roland’s Kakehashi prepared the details of what would become of MIDI. “If we had done MIDI normally, it would have taken years and years to make the standard,” said Mr. Smith told Waveshapper. “You have committees and documents and da-da-da. We just bypassed it all by basically doing it and then throwing it there. “
In 2013, Mr. Smith told St. Helena Starr: “We made it low cost to make it easier for companies to integrate into their products. It was licensed for free because we wanted everyone to use it. “