Laboratory measurements of conical reed woodwinds in a Physics of Music class

Abstract

In our Physics of Music class for non-science majors, wind instruments are initially modeled by studying resonances of open and closed (i.e., one end closed) cylindrical tubes. Among the woodwinds, flutes and clarinets fit the open and closed cylinder models quite well. However, the acoustical properties of closed (i.e., reed driven) conical woodwinds, such as oboes, bassoons, and saxophones, are less intuitive and more difficult to motivate in a course for non-science majors. The laboratory exercise described here employs a straightforward analysis of simple dimensional measurements of bore profile and tone-hole location to verify a few of these properties, and to illustrate some of the acoustical differences between flutes, clarinets, and conical woodwinds. For pedagogical reasons described in this presentation, a straight soprano saxophone provides an ideal prototype for this study, although more commonly available alto and tenor saxes can also be used.