THE SCIENCE AND APPLICATIONS OF ACOUSTICS - H. H. Arnold ...

544 18. Music and Musical InstrumentsFigure 18.30. Reed organ pipe and reed mechanism.the pipe determine the timbre. Voicing is the process of selecting and adjustingthese components to yield the proper timbre. Reed organ pipes are generally designedto imitate orchestral instruments such as the trumpet, tuba, oboe, clarinet,the human voice, and so on. These pipes are classified as chorus and orchestralreeds.The clarinet consists of a single-mechanical reed coupled to a cylindrical tubewith a flared open end. Control over the effective length of the resonating air columnis provided by a number of holes that may be opened or closed by fingers, eitherdirectly or through keys. Any change in the effective length of the air columnresults in a change of the resonant frequency. The reed position in the bottomof the mouthpiece functions in the manner described above for Figure 18.28.The throttling action of the reed changes a steady air stream into a saw-toothedpulsation that contains the fundamental and its harmonics. When sounded alone,the reed produces a sound rich in harmonics. The quality of the tone is improvedwhen the reed is coupled to the cylinder air column. The clarinet produces a rangecovering more than three octaves, from D 3 to F 6 . The clarinet’s overall lengthis about 63 cm. The bass clarinet is a larger instrument, being 94 cm in overalllength, which produces tones in a lower frequency range, from D 2 to F 5 . This lowerfrequency range is obtained by doubling the tube on itself.The saxophone operates in a similar fashion to the clarinet. The principal differencein its construction is that the diameter of the tube at the reed end is smaller,thus resulting in a lower acoustic impedance. Also, the coupling between the reedand the pipe is not as intimate as in the case of the clarinet. The buildup of the reedvibration is extremely quick, producing a sharp attack that is characteristic of thesaxophone. Saxophones come in various sizes, including soprano, alto, tenor, baritone,and bass. The smallest of these, the soprano saxophone, employs a straight