K. Stockhausen, Ypsilon for a melodic instrument with micro-tones (1989, flute version).

Notes at Stockhausen Edition no. 28 by Sonoloco

“Ypsilon” is a Greek letter symbolically used to indicate variable quantity. Stockhausen’s composition with the same name from 1989 is scored for “a melody instrument with micro-tones”. The composition can be performed on any wind instrument that has keys or valves. Stockhausen has given the piece a graphical score in 16 pitches. He has indicated that the intervals between the pitches should be “as small as possible but clearly perceivable”. That is what he means by “variable quantities”, since the steps of the intervals depend on the instrument and the player. “Ypsilon” for flute was worked out by Kathinka Pasveer in 1990. Again the melody is that of the Eve-formula, here starting with the central pitch of “Dienstag aus Licht” (“Tuesday from Light”) but stretched to 9 minutes and compressed spatially into approximately a minor third.
The rattling of bells startles at first. The costume of the player is saturated with Indian bells (compare the costume of the birdman Miron of “Musik im Bauch”!). The clicking of the valves adds another dimension to this fabric of sounds, and the human sounds of kissing, combined with other human – vocal – sounds, further the impression. Small pauses are inserted into the progression of events, and sometimes the shaking of the Indian bells reign in supremacy. The player achieves this by shivering!
This is one strange piece of music, which easily transports the suggestive listener into alien levels of experience!