Tom Huber, Brian Collins: Gustavus Adolphus College
Charles Hendrickson: Hendrickson Organ Company
Mario Pineda: Polytec PI Incorporated
The vibrational modes of a G#5 Trumpet reed
pipe were measured
using a Polytec PSV-300 Scanning Vibrometer.
The pipe has a conical resonator 14 cm in length, diameter of 1.1 to 4.6,
shallot 5.6 mm in diameter, reed with round end and a vibrating length of 8.5 mm
Scanning vibrometer measurements of displacement of the reed from its equilibrium position for a pipe blown in a standard fashion. Each successive image downwards corresponds to a phase shift of 90 degrees. The arrow with a W indicates the wedge, T indicates a section of the tuning wire, N indicates position of nodal lines. Image b is rotated to illustrate torsional motion of the reed, and the remainder are rotated to show several cantilever modes.
For animations of these modes, click anywhere on any of the harmonics
(since these are large AVI files, they make a while to load)
Click on any Harmonic to see the Vibrometer Mode
(a) The acoustical spectrum measured using a microphone 40 cm from the pipe
(b) The average velocity spectrum measured for pipe blown in a standard manner
To view animations of these modes, click on any of the peaks in the spectrum
(since these are large AVI files, they make a while to load)
(c) The average velocity spectrum measured for a mechanically driven pipe in vacuum
(d) The same spectrum for mechanically driven pipe at atmospheric pressuer
To view animations of these modes, click on any of the peaks in the spectrum
(since these are large AVI files, they make a while to load)