Shigeru Yoshikawa

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Musical flue instruments such as the pipe organ and flute mainly consist of the acoustic pipe resonance and the jet impinging against the pipe edge. The edge tone is used to be considered as the energy source coupling to the pipe resonance. However, jet-drive models describing the complex jet/pipe interaction were proposed in the late 1960s. Such m...

This work aims to provide an overview of why and how wood is used in musical instruments, primarily strings, woodwind and percussion. The introduction is a description of the desirable properties of a musical instrument and how these relate to the physical properties of wood. A summary is given of the most important woods mentioned in this chapter,...

Mutes for brass instruments are placed in the bell and change the instrument resonance characteristics. Since the pitch, loudness, and timbre are then affected, brass mutes are important for musical expression. Our main focus is on the acoustical modeling of the straight mute for the French horn and the cup mute for the trumpet. The validity of our...

Representative Japanese bamboo flutes, the shakuhachi, nohkan, and shinobue are investigated from musical acoustic viewpoint. The end-blown longitudinal flute, shakuhachi has only five tone holes, and several cross fingerings causes pitch sharpening (called intonation anomaly) as well as characteristic timbre, particularly in the second and third r...

Aero-dynamical models of sound generation in an organ pipe driven by a thin jet are investigated through an experimental examination of the vortex-sound theory. An important measurement requirement (acoustic cross-flow as an irrotational potential flow reciprocating sinusoidally) from the vortex-sound theory is carefully realized when the pipe is d...

The radiation-directivity patterns of clarinets are measured using an artificial blowing system which can ensure stable and reproducible tones. A reed is set in a box-shaped mouth and driven by the high-pressured air from an air compressor after adequately adjusting the embouchure formed by artificial lips made of silicone rubber. Our measurement i...

Fundamental types of vortex behavior of the smoked air-jet at the starting transient in organ pipe models are visualized with a high-speed digital video camera. A tiny vortex formed just beneath the edge can promote tonal buildup; a larger vortex staying before the edge considerably retards tonal buildup by dividing the jet. Other vortex types appe...

Our present knowledge of the sounding mechanism in flue organ pipes seems to be well founded and fully evolved through a long history of the research originated by Helmholtz and Rayleigh. However, if we define the sound excitation as the initial change from a nonsonic to a sonic fluid motion, there is no ab initio theory of the sounding mechanism b...

The controversial problem of whether a brass player's lip movements are best modeled as outward striking or as upward striking is approached by measuring the phase difference between mouthpiece pressure and lip displacement. In analogy with the phase of the input impedance to a resonant system, the negative/positive value of this phase difference s...

Over a century ago, Helmholtz classified reed instruments as those which tend to blow closed as the blowing pressure increases (the mechanical reed instruments), and those which tend to open as blowing pressure increases (the lip reed instruments). All subsequent work has tacitly assumed that these models are correct, and although measurements on c...

The principle and signal-processing method of generalized near-field acoustical holography (GENAH) to visualize the vibration of radiating surface are described. While the conventional acoustical holography is based on the acoustic pressure in far field, GENAR on that in near field. Much higher completeness of transformation of the measured field p...

A common theory is proposed to analyze the excitation mechanisms in woodwind and brass instruments. The cyclical process of sound production is mathematically formulated on the feedback principle and illustrated with the electrical circuit. This paper concentrates on the basic conditions for the steady-state self-oscillation in small amplitudes and...

A whole view on the harmonic generation in organ pipes is presented. It consists ofelementary processes:(a) excitory source spectrum generation by the jet, (b) filtrationby the inharmonic normal modes of the passive system, and (c) radiation from the pipeends. Lateral jet velocity distribution is responsible for the source spectrum. Filtrationand r...

The self-excitation possibility of underwater organ pipes as the counterpart of aerial ones is considered. Despite of the great differences between water and air, the organ pipe sounds in water as well as in air. The water-jet velocity is formulated by assuming the turbulent jet with weak additional decay. The velocity of the underwater sound propa...