An Italian synth and keyboard manufacturer that existed from about 1979 to 1987. One of its first products was a string synth called the Orchestra, which is notable mainly because ARP imported it and re-badged it, with minor modifications, as the Quartet. Its best known synths were the Opera 6 / DK600 / DK700, a series of polyphonic synths released in the mid-1980s, and based on integrated circuits from SSM.
Roland bought out SIEL in 1987. Roland only wanted the company's sales and distribution channels, in order to establish a new European distributor to replace one who had gone bankrupt. Immediately after the acquisition was complete, Roland discontinued all SIEL products. The Opera 6, DK600 and DK700 are now moderately sought after on the collector's market.