THE ELECTRONIC WORKS OF GYÖRGY LIGETI AND THEIR ...

Some of the invariant gestures which occur towards the end of Section E and
beginning of Section F occur in fragmentary form. Some of these appear to be made from
a combination of two ring-modulated invariant gestures where the end of one gesture
connects to the beginning of another. While the ring-modulated gestures shown earlier
expanded and then contracted forming a diamond-like shape in the spectrograph, these
fragmentary gestures contract and then expand again, forming more of an “X” shape than
a diamond. Examples of these at 2'25.5" and 2'27.5" are centered on 6400 and 3200 Hz
respectively, and thus have the same center frequencies as the gestures already heard.
Others similar gestures have differing center frequencies, and might have been formed
through separate ring modulation of a center frequency with a low-frequency glissando in
the other direction–down and then back up. The instance at 2'28.5" is one example of this
new shape, which occurs on a new center frequency of approximately 400 Hz, and
subsequent entries in Section F, such as the have 2'42", share this 400 Hz range, or
establish an octave transposition of this, as do the entries at 2'47", 2'54", and 3'03".
Section F.
An extremely low sine-tone glissando begins Section F (2'38"-3'46.5"), which
continues as a massive crescendo and build in register from the lowest to the highest
extremes heard in the piece. This culminates at the midpoint of the piece, where Ligeti
begins to overlap the prime and retrograde forms of the entire first half, and subject these
to filtering. The material of Section F is familiar from before, including invariant gestures,
glissandi of sine tones and filtered noise, and unfiltered noise–the most diverse materials
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