This is a piece for pitched sounds of Marimba. Computer models for signal processing as well as algorithmic approaches for horizontal and vertical nuances have been used in most of the composition. This composition is another triptych framed as the upper points of a cross. Each line of the cross is built upon two tone rows previously used in Yapaya and borrowed from Luigi Dallapiccola. The two orthogonal sequences obviously intersect at one point, however, points slide either way. Groups from each row cast trichords, tetrachords, and other features as well as threading of horizontal textures. Symmetrical elements in combinations of notes function as construction elements such as those used in tiling and tessellations. These elements are mixed to create sequences of notes always as cycles or palindromes. But they also create vertical groups. Hence, this approach translates into a geometrical interpretation of methods and heuristics on the conception of events for score-files. Thereby, objects can be transposed, displaced, rotated, compressed, or expanded in order to achieve a tiling or pattern. For do_Marin-Ta symmetries are inspired on the Esrefoglu pattern (see sketches below).
SKETCH No.1: Basic tile for the Esrefoglu pattern.
This pattern is found at the Esrefoglu Mosque at Beysehir, Turkey. Here we are outlining rhomboid shapes, although in its original rendition stars and cubes can also be perceived. Notice that triangles and diamonds are tilted, rotated, compressed or enlarged, among other operations. Note also that this figure is symmetric to the left or right within an axis in the middle of its base. Operations of this sort can also be done on tone row's subsets like trichords and tetrachords.
SKETCH No.2: Symmetrical combinations using the Esrefoglu pattern.
On this sketch four hexagons containing triangles and rhomboids intersect at each other, but on the whole give the impression of tri-dimensional cubes as product of their symmetries. This is an example of generative semantics, provided that we know the definition of a cube. Perception of this kind can happen while listening to sequences of acoustical events.
For the purpose of electroacoustic composition, symmetrical features are obtained from permutations of pitch-class-sets (PCS) and are not necessarily perceived as diatonic, melodic or harmonic. They are better understood as acoustical events that create tensions or equilibrium as they occur on the time-line of a score-file. Nevertheless, their image is not recorded in memory as in traditional means of melody and harmony. Therefore, and from a perceptual standpoint, resemblance to geometrical shapes arises since features are recognized as soon as perceived but intricacies are seldom memorized. It is known that a symmetrical combination can blend to create more symmetry, and thus mixtures of PCS resemble patterns and tiling comprised of hexagons, rhomboids, diamonds, triangles, and so on. Sound-wise matching of visual patterns in this piece is not really direct but somehow graphic and acoustic events produce sets of generative grammars in their own domains. Semantics of symbols in either or both domains might enlighten conceiving and apprehending pitched sounds, perhaps resembling other arenas where spontaneity and prepared improvisation dictate the norm.
On do_Marin-Ta, a set of tools developed in Lisp and Scheme by the composer for processing tone-rows resulting in symmetrical combinations were used in addition to Rick Taube's Common Music (CM), Bill Shottstaedt's S7, Snd and Common Lisp Music (CLM), as well as Joe Anderson's Ambisonics Toolkit (ATK). Fernando Lopez-Lezcano Grani and Dlocsig spatial tools were also on the palette, all implemented on PlaneCCRMA Linux workstations.
Perhaps you might want to Listen to "do_Marin-Ta" ?
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... Compressed UHJ Ambisonics down mix of ``do_Marin-Ta''