Figure 1: The sound spectra produced by several musical instruments playing the same tone (C$_4$, $f=262$ Hz) analyzed and recorded by J. Hughes using the program fftscope by H. S. Lu. The vertical dashed lines indicate the frequencies of harmonic overtones. These spectra are only broadly representative of their respective instruments and will differ depending on the performer, how loud the note is played, what portion of the note (e.g., attack, sustain) is analyzed and so on. Some features to note are the following. The second harmonic of the clarinet is suppressed as expected given that this instrument has a closed conical bore and should only show the odd harmonics. Note as well the inharmonicity of the piano overtones (green), which become especially noticeable for the highest overtones (green peaks shifted to the right compared to the dashed curves). See section 14.2 (p. 313) of the textbook The Science of Sound, 3rd Edition, by T. D. Rossing, F. R. Moore, & P. A. Wheeler (RMW) for more details on piano strings.
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Figure 2: The sound spectra produced by blowing through saxophone and clarinet mouthpieces alone. These are perceived as nasty squawking sounds! Single reed mouthpieces like these work in conjunction with the main body of the woodwind instrument to produce pleasing sounds at the resonance frequency of the pipe through a positive feedback process (see section 12.1, p. 247, of RMW for more details).
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John Hughes 2002-04-05