Dennis Colin was a key engineer at ARP Instruments who designed some of the company's most successful preset and ensemble-oriented synthesizers of the mid-1970s.

Colin engineered the ARP Omni, one of the first polyphonic string synthesizers with a full polyphonic brass section, combining divide-down oscillator technology with ARP's filter expertise. The Omni became a best-seller and defined the lush ensemble sound heard across disco, rock, and jazz fusion.

He also designed the ARP Solus, a performance-oriented monophonic synthesizer with footpedal control and preset voice cards aimed at stage keyboardists. Colin's work emphasized immediate playability — a contrast to ARP's earlier modular and Odyssey instruments that required more programming knowledge.

Notable products: ARP Omni, ARP Solus.