Stimmung

Stimmung, for six vocalists and six microphones, is a piece by Karlheinz Stockhausen, written in 1968 and commissioned by the City of Cologne for the Collegium Vocale Köln. Its average length is seventy-four minutes, and it bears the work number 24 in the composer's catalog.
It is a tonal, and yet also a serial composition. It is "the first major Western composition to be based entirely on the production of vocal harmonics", the first "to use overtones as a "primary" element". An additional innovation is "the unique kind of rhythmic polyphony which arises from the gradual transformation/assimilation of rhythmic models".
Title.
The German word "Stimmung" has several meanings, including "tuning" and "mood". The word is the noun formed from the verb "stimmen", which means "to harmonize, to be correct", and related to "Stimme" (voice). The primary sense of the title "implies not only the outward tuning of voices or instruments, but also the inward tuning of one's soul". According to the composer, the word 
Overview.
"Stimmung" is in just intonation. Six singers amplified by six microphones tune to a low B1 drone, inaudible to the audience, and expand upwards through overtone singing, with that low B's harmonics 2, 3, 4, 5, 7, and 9 (B2, F2, B3, D4, A4, and C5) becoming in turn fundamentals for overtone singing. It is composed using what the composer calls moment form, and consists of 51 sections (called "moments").
The harmonies of "Stimmung" are composed from 108 pitches: twelve different tones for each of the three women's voices, and twenty-four for each of the three men. Not only do the performers produce partials from the overtone series in each note they sing, but all of the fundamental tones are also related by whole-number overtone ratios. In this way, overtones are composed upon overtones, generating a range of degrees of harmonic fusion.
According to the 1986 Hyperion Singcircle liner notes:
The order of the rhythmic models and the distribution of the poems and "magic names" are decided by the performers, but the sequence of pitches in the 51 moments is fixed. Though the 1968 "Paris version" used by the Collegium Vocale Köln at the world première has been published (as No. 24½ in Stockhausen's catalog), the 1977 "Singcircle version" (directed by Gregory Rose) has been well documented in Rose and Emmerson 1979, and both versions have been performed throughout the world. Singcircle performances include the Round House on 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 directs. 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 (archived from 20 July 2007), 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 "Stimmung"s one-note idea back to the pedal point in Henry Purcell's "Fantasy upon One Note", and its time-scale to Wagner's "Götterdämmerung", while at the same time observing that this time-scale "indicates the need of a musical equivalent to the parking meter".
"Stimmung" had an enormous impact on many younger composers and has been cited as an important influence on the French spectralists of the 1970s, such as Tristan Murail and Gérard Grisey.