 The sequencer would completely control (i.e., "play from memory") the synthesizer; however, leaving the musician with no way to play along live on the instrument's keyboard, this also identified a problem that inspired Oberheim to design a Synthesizer Expansion Module (aptly named the SEM) with the design assistance of Dave Rossum (later of E-MU Systems fame), that facilitated simultaneously recorded + live playing (akin to the multi-track audio recording practice of "overdubbing" also associated with "sound with sound" and "sound on sound" recording).Oberheim first showed the SEM, which was the first synthesizer bearing his company's name, at the Audio Engineering Society convention in Los Angeles in May 1974.The following year, when Norlin (CMI's successor) cancelled several large orders for Oberheim's Maestro products, Oberheim shifted his design and manufacturing efforts to replace that lost business.