"When one vibrating body causes another to vibrate—exciting it, as they say in acoustics—the effect is called 'vibrational coupling.' I'm tuning the low E-string back up to pitch. Like peeking into the instrument's shadowy basement... as I turn the tuning peg, the string climbs back up the step, causing different sections of the instrument to vibrate. My right thumb stricks the string, and it boings E-ward, exciting the sliver of bone, called the bridge, on which it rests. The bridge in turn excites the saddle that holds it in place, the saddle communicating this motion to the guitar's face, which then vibrates with the string's frequency, producing an audible tone, which excites me."
—Glenn Kurtz, Practicing: A Musician's Return to Music (New York: Vintage Books, 2007), 137