21 November 1977, a 1977 BBC Promenade Concert at the Royal Albert Hall, in Liverpool's Anglican Cathedral as part of the 1980 Hope Street Festival, and at the Barbican in 1985, with the composer at the mixing desk. Singcircle's performance at the 2005 City of London Festival was recorded and broadcast on BBC Radio 3's Hear and Now on 20 August 2005. In 2003, Paul Hillier made a "Copenhagen version" for the Theatre of Voices, which he directed. This version, too, has been performed on tour, and a recording has been released on CD. Other groups that have performed Stimmung include the London Sinfonietta Voices, Ensemble Belcanto, Neue Vocalsolisten Stuttgart, the Aquarius Consort, and the Dunedin Consort, according to the performance database of Universal Edition. Influences and reception Stockhausen himself attributes a month spent walking among ruins in Mexico as his primary influence, Stimmung recreating that 'magic' space. On the other hand, he also describes the snow on frozen Long Island Sound in February and March 1968 (when he was composing Stimmung in Madison, Connecticut), as "the only landscape I really saw during the composition of the piece". In a letter to Gregory Rose written on 24 July 1982 (printed in the liner notes to Hyperion CDA66115), he describes how, in the small house his wife Mary had rented it was only possible for him to work at night because their two small children needed quiet during the day. He could not sing aloud, as he had done initially, but began to hum quietly, listening to the overtone melodies. Mary reports that Stockhausen first discovered the technique when listening to their small son Simon producing multiple tones while humming in his crib after falling asleep. In this way, Stockhausen became "the first Western composer to use this technique of singing again—in the Middle Ages it had been practised by women and children in churches, but was later entirely supplanted by masculine Gregorian music". Some writers have seen the possible influence of Stockhausen's student La Monte Young and his mid-1960s drone music with The Theatre of Eternal Music: However, another precedent for Stimmung is an unfinished work by Stockhausen himself, begun in 1960 and titled Monophonie, which was to have consisted of the single note E. Igor Stravinsky, on the other hand, traces Stimmungs one-note idea back to the pedal point in Henry Purcell's Fantasy upon One Note, and its time-scale