Bowed strings sustain high harmonics indefinitely while plucked strings lose them quickly

Evidence

The force shown in figure 18.4 abruptly switches sign just as it is largest in magnitude, as the kink collides with the bridge. The force steadily diminishes until it vanishes, then builds up again with the opposite sign, only to repeat the abrupt change after one period. The result is a sawtooth waveform for the force as a function of time, as seen in black in figure 18.5, which also shows the Fourier components of the sawtooth and raises the issue of their relative phases. The force perpendicular to the string is shown in figure 18.3. The waveform of the force on the bridge is very nearly a sawtooth, rich in high harmonics. These higher harmonics contribute to the rich timbre of the violin; they are maintained as long as the bowing continues, whereas the higher harmonics in a pluck soon decay. — Eric J. Heller, Why You Hear What You Hear- An…, 1751

Categorization

• XREF: Connects to Fourier analysis and harmonic spectra from earlier chapters on waves and resonance.
• DEFINE: Explains why the violin’s bowed tone is sawtooth-rich in harmonics and why bowing sustains brightness that plucking cannot.