Instrument timbre comes from waveform shape, not pitch

Evidence

Figure 3.1 also shows the acoustic pressure waveforms produced by other instruments when A4 is played. While the periods and therefore the f0 values of these notes are similar, their waveform shapes are very different. The perceived pitch of each of these notes will be A4, and the distinctive sound of each of these instruments is related to the differences in the detailed shape of their acoustic pressure waveforms, which is how listeners recognize the difference between, for example, a violin, a clarinet and an oboe. This is because acoustic pressure variations produced by a musical instrument that impinge on the listener’s tympanic membrane are responsible for the pattern of vibration set up on the basilar membrane of that ear. It is this pattern of vibration that is then analyzed in terms of the frequency components of which they are comprised (see Chapter 2). If the pattern of vibration on the basilar membrane varies when comparing different sounds, for example from a violin and a clarinet, then the sounds are perceived as having a different “timbre” (see Chapter 5) whether or not they have the same pitch. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 786

Categorization

• XREF: Connects to the reader’s existing library on soundscape and listening (The Soundscape, Deep Listening) — the physical mechanism by which timbre is encoded on the basilar membrane. — connects to: Instruments sharing pitch sound different because waveform shape drives basilar-membrane timbre — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 786