Bells, electronic carillons, and chimes

Bells and chimes, unlike the more familiar string and wind instruments, produce tones in which the overtone structure cannot be expressed as a series of harmonics. The accuracy of tuning of the various overtones varies widely but the better cast bell carillons, electronic carillons, and tubular chimes do have very accurately tuned overtones. This paper describes the results of measurements on cast bells, electronic carillons, and tubular chimes. Data will be given on relative amplitude and decay rates of the various overtones. The reaction of "out-of-tuneness" will be discussed and explained. A new type of tone source for electronic carillons will be described. With this new tone source, a rod of carefully controlled rectangular cross section is used. This rod can give in a single unified structure essentially the same overtone array as that of an accurately tuned cast carillon bell.