The basis for "The Gates of H." by Ludger Brümmer is an already existing piece of music which is then altered dynamically by different algorithms.

"The Gates of H." uses as the source-sound, a sample of a folk piece sung by a Bulgarian female choir. The idea of using an already existing piece of music for a new composition is to put a new structure above the source-piece creating a tension between the original structure of the source-sample and the structure generated by algorithms. It is the mixture between two different time concepts, where the listener understands sometimes the algorithmical, sometimes the source-sound layer, sometimes both layers, in its structure. The source-sound has the function of being the known reference, which is then restructured by the parameter constellations of the algorithms. The dynamic modifications (crescendo /decrescendo), forward or backward, the new time position of the sound, and the durations together with the pitch conversion create this masking effect of the source-sound, so that the image of a voice is sometimes clear and recognisable, but sometimes not. The same masking effect influences the harmonic structure of the piece in that the tonal character of the Bulgarian folk song interferes with the pitch structure of the algorithms. This technique switches the recognizable image between the source sound and the algorithmic image.
The algorithms use one central idea: one or more values increase or decrease at different speeds between two mobile limits. These values are then applied to different parameters. The first sound, for example, is generated by a pitch bouncing up and down while the time value bounces forward and backward between the beginning and the end of the sound. In this case, several (up to five) different values decrease and increase as the values are used one after the other.
The formal structure of the piece is determined by accents, continuous dynamic levels and increasing dynamic levels. The composition itself starts with two extreme dynamics. While the first 340 seconds have only very soft or very loud levels (subito ff or subito pp), and accents, the following part develops increased dynamic parts with long crescendi and decrescendi. These dynamics are augmentations of the beginning dynamic switches, where a fast crescendo is perceived like an accent or subito ff. Throughout the piece the accents combine to form more and more complex accent groups which grow into structures audible in seconds 818-850 of the piece, where two transpositions of the developed accent group are audible.

Ludger Brümmer (D), born 1958. 1978-1983 Study of psychology / sociology at the Universität Dortmund. 1980-1983 additional studies in music and art. 1983-1989 studies in composition at the "Folkwanghochschule" in Essen with Nicolaus A. Huber (instrumental composition) und Dirk Reith (electronic composition).1990 musical director at the theater in Bruchsal. 1990 technical director and workshop trainer at the Kamener Komponistenforum. 1992 work with the Nederlands Dansteater and the Ballett Orchestra, Den Haag for the piece "!Tristan und Isolde!" where the piece for orchestra "Riti Contour" was played several times. 1991-1993 scholarship at the "Center for Computer Research in Music and Acoustics" (CCRMA) at the Stanford University California. 1993 teaching position at the electronic Studio of the Folkwanghochschule Essen (ICEM).