Related Experiment Video
Updated: Jun 6, 2026

Measurement of Chladni Mode Shapes with an Optical Lever Method
Published on: June 5, 2020
Influence of wall vibrations on the sound of brass wind instruments
Wilfried Kausel1, Daniel W Zietlow, Thomas R Moore
1Institute of Musical Acoustics, University of Music and Performing Arts, Anton von Webern Platz 1, A-1030 Vienna, Austria.
Abstract:
The results of an experimental and theoretical investigation of the influence of wall vibrations on the sound of brass wind instruments are presented. Measurements of the transmission function and input impedance of a trumpet, with the bell both heavily damped and freely vibrating, are shown to be consistent with a theory that assumes that the internal pressure causes an oscillation of the diameter of the pipe enclosing the air column. These effects are shown to be most significant in sections where there are flaring walls, which explains why damping these vibrations in cylindrical pipes normally produces no measurable effects.
Related Concept Videos
Sound as Pressure Waves
The pressure fluctuation depends on the difference in displacements between the successive points in the...
Sound Waves: Resonance
Sound Waves: Interference
Standing Waves
Modes of Standing Waves: II
For a tube open at one end and closed at the other filled with air, the modes are such that there is always an antinode at the open end and a node at the closed end.
Modes of Standing Waves - I

