At school, Haigh was in a band called Labyrinth playing original material that was influenced by David Bowie and Roxy Music. In the early 1980s Haigh released a series of experimental ambient albums under the names Robert Haigh and Sema. He also contributed to several Nurse With Wound projects and formed an industrial avant-funk band called The Truth Club together with Trefor Goronwy, who would go on to join This Heat.
In the 1990s, Haigh developed a unique style of what has become known as ‘ambient drum 'n' bass’ and released six EPs and six albums under the name Omni Trio to great acclaim. Omni Trio was one of the original drum 'n' bass producers, who first released for Moving Shadow as early as 1993. Following the release of the sixth and final Omni Trio album Rogue Satellite in 2004, Haigh decided to cease recording as Omni Trio.
On his decision to cease recording as Omni Trio he has said: "After Even Angels Cast Shadows and especially the minimal structures of Rogue Satellite, I felt that perhaps my work was done in this particular area. All along the intention was to do the Omni Trio stuff alongside producing and releasing piano based material under my own name. Then the Omni thing blew up much bigger than I had anticipated. But throughout the '90s I also kept writing piano and minimal themes. By the early 2000s the time seemed right to put the emphasis on developing this material." Following Omni Trio, Haigh released a number of modern classical and minimalist albums under his own name for a variety of labels, culminating in a trio of albums for Unseen Worlds (Creatures of the Deep, Black Sarabande, Human Remains), which would also mark an intentional pivot away from album production.