terça-feira, 25 de dezembro de 2012

Basic ideas and methods


7.Basic ideas and methods

The basic idea behind our investigation on wind instruments was that respiratory acts in playing derives their characteristics from three different realms, (1) the acoustical properties of the instrument, (2) the physiological characteristics of the player, and (3) the musical demands of the score. As illustrated in Figure 1, these three realms are closely intertwined. To elucidate the relations between them, more detailed descriptions of the associated phenomena are needed. Such descriptions must be based on experimental work, requiring the use of an ensemble of methods of measurement as well as the selection of appropriate tasks.

Our research has been done with the assumption that the knowledge gathered from a predominantly physical approach should preferably be complemented by measurements collected under conditions that appear realistic to the players. This can be expected to result in additional and relevant aspects of the instruments influenced by the human factors in the relationship player/instrument.

The subjects in all wind instrument studies were adult healthy players, representing the western classical tradition. All subjects were either professional or semi-professional with more than 10 years of continuous experience. This was motivated by the belief that successful and experienced players use their instruments in a way that involves several processes of optimisation. Such optimisation can be expected as a result from long-term learning and experience and should lead to automated behaviour. This does not imply that there is a unique solution to any given performance problem, posed by the music, the instrument or the player’s physiological abilities and constraints. On the contrary, players can be expected to tailor their solutions to conditions represented by their instrument, and to their personal preference and physiology. No more than two players were used for each instrument. This was considered sufficient for the questions raised in the thesis, its main aim being to describe and explain aspects of wind instrument playing of players who are sufficiently skilled to earn their livelihood from playing. On the basis of our results, variations of playing technique should be more meaningful to examine in the future.

The experimenter strived for establishing a professional relationship with the subjects. All subjects were paid for their services, as artists should always be compensated when their professional competence is used. Moreover the payment may have contributed to eliciting a professional attitude to the solution of the various experimental tasks which were sometimes repetitive and demanded a high degree of concentration. The experimental sessions lasted for a full hour, approximately. The subjects were minimally informed about the purpose of the experiments.

It was considered desirable to ask the subjects to perform musically common tasks, such as scales, arpeggios, and well-known music examples. This was expected to induce their typical instrument playing behaviour.

Because the use of typical playing conditions was a main concern, methods that the player could regard as invasive or disturbing were avoided as much as possible. For the studies involving blowing pressure measurements, Papers I-II-IV-V, a thin pressure sensor (Gaeltec CTO-2 strain gauge catheter, 2mm diameter) was inserted in the player’s mouth corner and fixed to the face with adhesive tape. According to the subjects, this only marginally affected their embouchure. The respiratory inductive plethysmography (RIP) technique, applied in Paper V, is in essence a non-invasive method, since it measures external surface variations to infer internal thoracic volume changes. For the sake of accuracy, a fixed and rather symmetrical body posture is required. On some rare occasions the subject failed to meet this demand which caused interruption of the recording. In all such cases the professional player then promptly and successfully accomplished the repeating of the task with a stable posture. The use of the pneumotachometer (or electrospirometer) in Papers II-IV-V, did not cause any difficulties, since the subjects inhaled through it after exhalatory tasks, the mouthpiece being available from the hands of the experimenter whenever necessary.

In the investigation of vocal-ventricular phonation, Paper VI, several methods were used. For measuring the glottal flow, a Rothenberg mask (Rothenberg, 1973) was attached to the subject’s face, covering the mouth and the nose. This did not appreciably disturb sound production. In obtaining the images from the glottis by high speed filming, a rigid telescope was inserted in the subject’s mouth and held by the medical expert in the pharynx, allowing view of the ventricular folds. This method is clearly invasive, but it could successfully be applied after some attempts. For the preliminary videolaryngo-stroboscopy technique, a thin fiberoptic catheter was inserted through the nose and placed above the larynx. This did not disturb sound production. In recording subglottal pressure, a thin catheter was inserted through the nose, placed in the esophagus below the level of the larynx. Local anesthesia was required to prevent irritation and disturbance of voice production.

In the present thesis, we have strived for selecting questions which are both acoustically and musically relevant. In designing experiments a basic idea was to take advantage of the artists’ skills and long-term experience, thus hopefully attaining information collected under musically realistic conditions. Moreover, it was considered important that the scientist understand the artist’s frequently intricate questions.

©1998 by Leonardo Fuks



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