Percussion instruments divide into bar, membrane, and plate classes

Evidence

Percussion instruments are characterized acoustically by the modes of vibration they are able to support and the position of the strike point with respect to the node and antinode points of each mode (e.g., see the discussion on plucked and struck strings earlier in this chapter). Percussion instruments can be considered in three classes: those that make use of bars (e.g., xylophone, glockenspiel, celeste, triangle), membranes (e.g., drums) or plates (e.g., cymbals). In each case, the natural mode frequencies are not harmonically related, with the exception of longitudinal modes excited in a bar that is stimulated by stroking with a cloth or glove coated with rosin, whose mode frequencies are given by Equation 1.35 if the bar is free to move (unfixed) at both ends and equation 1.36 if it is supported at one end and free at the other. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1268

Categorization

• DEFINE: Three-way classification of percussion instruments by vibrating element type.
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1268
• XREF: connects to: Drum membranes always have one clamped-edge circular node; Nonharmonic natural modes give struck percussion instruments their clangy identity; Wind instruments divide into reed and non-reed sound-source types — David Howard, Jamie Angus, coustics and Psychoacoustics, 1160 (+4 more)

Broader Connections

• Wind instruments divide into reed and non-reed sound-source types #exemplifies (0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1160
• Percussion excitation is a short impulse rather than a sustained tone #expands (0.85)
• A free-edged cymbal plate produces inharmonic, mixed modes #exemplifies (0.80)
• Musical instruments are analyzed as input through a modifying system to output #expands (0.75) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1081
• Instruments spanning multiple vibration families resist clean classification #qualifies (0.75)