Effect of Wall Material on the Steady-State Tone Quality of Woodwind Instruments

Abstract

A clarinet blown with an artificial embouchure was connected to one end of a large pipe with absorbing material at the other end so that the sound usually radiated was absorbed instead. Under these conditions, the sound radiated from the vibrating body was measured and found to be 48 dB below the sound normally produced by the instrument at the same location. Acceleration levels measured on the body with a vibration meter were correlated with the sound radiated by the body, both for the artificially blown clarinet and for clarinets set into vibration with an attachment energized by a complex signal. The figures obtained were used to check other woodwind instruments. Results showed that the body sound should be at least 37 dB below the normal sound for all instruments measured. The effect of nonrigid walls was checked by comparing tubes of brass and soft TYGON plastic blown on the embouchure, measuring the harmonic structure of the internal standing wave produced and the frequencies and Q's of the resonance modes. The differences were small. It is concluded that the vibrations of the walls of a woodwind instrument do not affect its steady tone either by radiating sound themselves or by affecting the harmonic structure of the internal standing wave.