When Tom Oberheim launched his company in 1969, he probably didn’t realise the influence his designs would have. His initial products were based around effects processing, followed swiftly by one of the first digital sequencers. But it was the appearance of the Synthesizer Expander Module (SEM) in 1974 that captured the imagination of musicians and≈synthesists, which continues to this day.
The one and OB
The SEM was (and is) a monophonic synth voice, replete with two oscillators, variable-state filter, envelopes and LFOs. It was designed to act as a voice-partner for the Oberheim DS-2
