( Tape Music for Spectral and Physical Models of Cello )
[ Compressed mix of ``SygFrydo'' ]
This is a Digital Media composition generated by means of Physical, Spectral and Expression Modeling. The primary subject consists of Cello figures which are subsequently processed, in order to obtain the expressive qualities of the piece. This is done by analyzing the musical phrase in addition to its spectrum. The piece was composed in MOX Center for Advanced Computing at La Universidad de Los Andes in Bogotá Colombia. In this case several images of a cello sound are tied together by means of a thread producing a musical suggestion. Several suggestions then create an episode, resulting in tensions and distensions managed in the time domain. In this composition a priority was to use the musical gesture in a tape or frozen moment context.
The form of the piece follows literary counterparts of a war plot with episodes. For this purpose the notion of the musical drama was also supported by suggesting tension increase and tension release at different parts of the composition. There is character or rather hero in the history and the episodes narrate an evolution of different situations as time goes by. The story follows different episodes that describe a fight with other evil men in parallel with unsatisfied love. At the end, Sygfrydo is a warrior and saviour of its own glory by consequently fulfilling his love for the woman of the story. The character of Sygfrydo is one of heroic activity, physical strength and unawareness of his fear. Throughout this piece there is horizontal development analogous to melody as well as some harmony but the idea is the tone color of the cello and sonorities which might help to describe tone and contour to convey the mood or emotion of any particular instant in the musical episode.
Expression Modeling is achieved by isolating those parameters which the composer considers relevant to the composition. In this piece dynamics, rhythm, timbre and nuance were primarily isolated. Rubato and vibrato were also considered as very effective means of conveying expression from a musical performance because they belong to a specific moment and to the particular performance of the musical phrase performed by the cello. In this expression model, a single gesture was achieved by extracting parameters out of a spectral analysis file. Expression often changes in a time domain basis and therefore it was necessary to model these values by means of deterministic or stochastic values for predicting the necessary values in the phrasing of cello gestures. In several moments parameters like rhythmic and sound articulations were also accented in order to get a more natural development of the sound resembling the traditional performance therefore, time compression and expansion were applied to phrase duration.
Among the reasons for using sounds generated from a spectral and physical model of a traditional instrument is concerned to the richness of its timbre from a perceptual context. This provided a way to convey to expression modeling of known musical gestures in an instrument like the Cello. By working with this technique there is not only parametric sound generation but also values which control expressiveness in the model. By the other hand in this composition, the aim was to take advantage of both the lack of the interpreter and flexibility of a compositional medium namely the computer, to obtain sounds otherwise impossible with just the traditional instrument and a musician. Since there was instrument modeling , a specific physical object which already exists, there was a high degree of flexibility by generating sounds which come from an existent source, but at the same time do not exist in a traditional approach, precisely since our interpreter is the computer.
This piece was composed using software mostly developed at the Center for Research in Music and Acoustics, CCRMA at Stanford University in the U.S. SMS, Spectral Modeling System developed by Xavier Serra was used to perform analysis on Cello sounds and phrases. This analysis was thereupon used for the extraction of not only the spectral content of the sound but also to the extraction of such variables considered as expressive and musically meaningful. As a result, some of these analysis were consequently resynthesized also by means of SMS manipulation as Spectral Models. Analysis files were also used as parameters in envelopes for the algorithm of the bowed string suggested by Julius Smith also at CCRMA. Further synthesis of sound was done in Common Lisp Music (CLM) with the assitance of Bill Schottstaedt author of this software package. The Algorithmic Composition was performed by using Common Music (CM) and theCM/CLM combination. Most of this software was implemented by the composer on a DEC Alpha computer and Silicon Graphics computers at MOX, Center for Advanced Computing at La Universidad de Los Andes in Bogotá.