Doug Curtis (1951–2007) was the founder of Curtis Electromusic Specialties (CEM) and one of the most important yet underrecognized pioneers of synthesizer technology. Keyboard magazine called him "one of the most important and least known synthesizer pioneers of the 20th century."

Curtis began building synthesizers in high school and won a chip-design competition that launched his career at Interdesign. In 1979 he founded CEM, producing custom and standard analog integrated circuits used in synthesizers by Oberheim, ARP, Sequential Circuits, Moog, Roland, PPG, and dozens of other manufacturers.

His CEM3340 oscillator, CEM3320 four-pole filter, and CEM3310 envelope generator defined the "Curtis sound" — saturated, brash, and powerful — heard in the Prophet-5, OB-Xa, Memorymoog, Waldorf Wave, and many more. Dave Smith adopted Curtis chips for the Prophet-5 Rev 3, cementing their ubiquity.

Curtis closed CEM in 1988 to found OnChip Systems but his chips remain essential; OnChip reissued the 3340 in 2017, and modern instruments like the Sequential Prophet-5 Rev 4 and Oberheim OB-X8 use Curtis-derived designs.

Notable products: CEM3320 filter, CEM3340 oscillator (used in Prophet-5, OB-Xa, Memorymoog, Pro-One, and hundreds of other instruments).