Plucking position on a string suppresses modes with nodes there
Evidence
For example, if the string is plucked at the center, as indicated by the central dashed vertical line in Figure 4.6, modes that have a node at the center of the string (the second, fourth, sixth, eighth, tenth etc., or the even modes) are not excited, and those with an antinode at the center (the first, third, fifth, seventh, ninth etc., or the odd modes) are maximally excited. If the string is plucked at a quarter of its length from either end (as indicated by the other dashed vertical lines in the figure), modes with a node at the plucking point (the fourth, eighth etc.) are not excited and other modes are excited to a greater or lesser degree. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1083
Thus if the plucking point is a third of the way along the string, the modes not excited are the third, sixth, ninth, twelfth, fifteenth etc. For a component mode not to be excited at all, it should be noted that the plucking distance has to be exactly an integer fraction of the length of the string in order that it exactly coincides with nodes of that component. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1085
Categorization
- CANDY: A delightful, trivial-sounding fact: pluck a string exactly in the middle and you get only odd harmonics — why guitarists plucking mid-string sound softer and rounder.
- SEED: Could anchor an essay on how instrumental technique is physics in disguise: the harmonics a player suppresses by where they touch the string.
- corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1083; David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1085
- XREF: connects to: A string’s nth mode has n+1 nodes and n antinodes — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1081; Plucked-string spectra reveal the plucking point through nulled harmonics — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1127