DEVELOPMENT OF AN ELECTROLABIOGRAPH EMBEDDED IN A TROMBONE MOUTHPIECE FOR THE STUDY OF LIP OSCILLATION MECHANISMS IN BRASS INSTRUMENT PERFORMANCE

摘要

The lips of a brass instrument player constitute a complex pressure-controlled valve from which the vibration of the air column originates. Due to their anatomical properties and the significant ability from the player to control their geometry and mechanical properties, lip valve systems display different vibratory behaviours across the traditional range of playing. In order to investigate lip mechanics on real performers, different in-vivo methods have been proposed. Lip opening area and frequency response have been evaluated on real players using high speed imaging [1]. This technique requires the use of a special transparent mouthpiece with cylindrical cup that allows the capture of undistorted images but may significantly affect the behavior of the lips. Lip vibratory mechanisms have been investigated using strain gauges placed between the lips and the mouthpiece rim [2]. This solution remains however quite invasive since the strain gauge is usually attached to the upper lip of the subject. Experiments have also been conducted on artificial lip systems which allow the use of highly intrusive measurement devices such as laser velocimetry or light transmission and video methods [1,3]. However, although artificial lips are becoming more accurate at reproducing the lip behaviour of human performers, they are still approximations of human lips and have not proven yet their ability to reproduce human players' behaviour over all registers of a trumpet or a trombone.