Preview: Theatre Of Voices, Touring, Oxford, Manchester, Perth

The British singer-turned-conductor Paul Hillier is bringing his vocal ensemble Theatre of Voices to the UK to perform Stockhausen's 1968 masterpiece Stimmung. This meditative 70-minute piece, based on one chord, interweaves the voices of six singers seated around a table in the dark. The piece was influenced by Stockhausen's own mystical experiences in Mexico and Tibetan overtone singing.

"The chord is a very still sound, but it isn't quite as simple as singing one note," explains Hillier. "There are little musical events throughout the piece, still based on that chord, but with different sounds or syllables. There are also fragments of text and poems by Stockhausen that are rather erotic in content. They are in German, so not everybody will understand them."

The Theatre of Voices was formed by Hillier in 1990 to explore different singing techniques. He uses the ensemble to "focus on medieval and Renaissance polyphony and contemporary composers of the new tonality school and experimental work".

Hillier began his career in the choir of St Paul's Cathedral in London and later became a member of the Chapel Royal. He co-founded the Hilliard Ensemble before Theatre of Voices. He has close partnerships with modern composers such as Steve Reich, John Adams and Arvo Pärt.

"I am doing a number of concerts next year with Steve Reich because it is his 70th birthday," says Hillier. His work with Reich goes back a long way, and in 1994-5 he conducted Reich and musicians in the premiere performances of The Cave, a three-act video opera by Reich and Beryl Korot.

But Hillier never strays too far from the beaten track. "I always like to retain a connection to conventional classical music," he says.

Jacqueline du Pré Concert Hall, Oxford (01865 305305) 16 January; Bridgewater Hall, Manchester (0161-907 900) 17 January; Perth Concert Hall, Perthshire (0845 612 6324) 18 January