Where you strike a percussion instrument governs which modes sound

Evidence

In order that notes can be played which have a clearly perceived pitch on percussion instruments such as the xylophone, marimba and vibraphone—with playing ranges from C5 (523 Hz) to C8 (4186 Hz), A2 (110 Hz) to C7 (2093 Hz) and F3 (175 Hz) to F6 (1397 Hz), respectively—the bars are shaped with an arch on their undersides to tune the modes to be close to harmonics of the first mode. In the marimba and vibraphone, the second mode is tuned to two octaves above the first mode, and in the xylophone, it is tuned to a twelfth above the first mode. These instruments have resonators, which consist of a tube closed at one end, mounted under each bar. The first mode of these resonators is tuned to the f0 of the bar to enhance its loudness, and therefore the length of the resonator is a quarter of the wavelength of f0 (see Equation 1.36). — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1287 (#qualifies, via linked claim)

Categorization

• XREF: connects to: Strike placement on a drum excites modes by their amplitude at that point; A hammer strike excites every mode an instrument can support simultaneously — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1266; Nonharmonic natural modes give struck percussion instruments their clangy identity (+6 more)

Broader Connections

• Nonharmonic natural modes give struck percussion instruments their clangy identity #expands (0.95)
• Percussion bars are shaped to tune their modes toward harmonic ratios #qualifies (0.90) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1287
• A free-edged cymbal plate produces inharmonic, mixed modes #exemplifies (0.90)
• Percussion excitation is a short impulse rather than a sustained tone #expands (0.85)
• Loudspeaker position determines which room modes get excited, as with bowed strings #corroborates (0.85)
• Differing tensions on paired drum heads deliberately spread nonharmonic modes to sound nonpitched #exemplifies (0.80)
• Instrument stiffness versus tension determines how widely its modes are spaced #expands (0.80)