A comparison of wind instrument time-variant spectra
James W. Beauchamp · The Journal of the Acoustical Society of America · 1999
Musical instruments can be compared in terms of the sound spectra that they produce. First, they may be compared in terms of spectral envelope, which allows an observation of change of amplitude with respect to frequency. Moreover, the spectra change with respect to time, usually with a burst of low-amplitude, broadband spectrum initiating the attack phase, followed by a gradual increase of spectral centroid. The so-called ‘‘steady state’’ may actually include some interesting changes, depending on performance expressivity. The final decay phase is perhaps the least manipulable by the performer, and is generally characterized by a gradual lowering of the centroid as the amplitude decreases. A centroid-indexed family of spectral envelopes based on data for several tones with different fundamental frequencies gives a good average picture of the spectra for a particular instrument. However, this representation fails to take into account special details such as pitch-dependent and harmonic-dependent spectral features. While such special details are least important for the brass, they are very important for the woodwinds, and several features of the clarinet, oboe, saxophone, and flute will be illustrated and compared.