© 2001 James Walker
Tone Production on Mallet Instruments
It is important that mallet players have a basic understanding of tone production on their instruments. This lesson addresses two important factors: the selection of striking spots, and the basic mechanics of resonators.
I. Striking Spots
The spot on which one strikes the bars of a mallet instrument is crucial. Striking at the nodal point (i.e., the point at which the hole for the cord is drilled through a bar), will yield the minimum amount of fundamental from the bar, and the maximum amount of harmonics. Striking in the very center of the bar, will maximize the fundamental pitch - a fact which causes many players to favor the middle when selecting a striking spot. This diagram shows how the amount of fundamental tone changes along the length of the bar. (Note that this variance is a naturally occurring phenomenon, and that the holes for the cord are drilled at the nodal points; the nodal points are not created by drilling the holes.)
Here, an X is used to indicate spots on the bar which will yield a blend of fundamental pitch and harmonics:
If one wishes to have the sound of each mallet yield the same tone, the obvious choice is to strike each mallet in the same spot of the bar. Another option is to position one mallet in front of another, at points equidistant from the nodal points. Here are two common mallet positions:
A common misconception about mallet instruments is the idea that the resonators of a vibraphone, marimba, or xylophone, increase the sound of the bar. In fact, the added volume comes from the vibration of the air column within the resonator tube, drawing energy away from a struck bar. A resonator is tuned to (roughly) the same pitch as the bar above it, and when the bar is struck, the air column inside the resonator vibrates in sympathy, and the combination of the bar and the resonator creates volume.
Because of the transfer of energy from the bar to the resonator, the sustain of the bar is lessened. As an experiment, remove the resonators from a vibraphone or marimba, and you will hear that the bars sustain longer than they do with the resonators attached. This loss of sustain is the price paid in order to naturally amplify the instrument.
Vibraphones make use of the relationship between bar and resonator, to create the tremolo effect commonly associated with the instrument. As the rotor fans open and close (due to the rotation caused by the instrument's motor), the amount of energy being transferred to the resonator alternately increases and decreases, creating the tremolo (euphemistically referred to as "vibrato" by many players).
Even if a vibraphonist does not make use of the motor when playing, he/she can still make use of the rotors. Setting the fans fully vertical ("open") will maximize the volume of the instrument; setting them fully horizontal ("closed") will increase the sustain of the instrument. The player may set the rotors to any angle in between, to effect a particular balance of sustain and volume.
A future malletjazz.com lesson will address the ways in which a player's "sound" is affected by the use of certain mallets, and through the manipulation of a player's technique.
(This page and all the materials within copyright ©2001 James Walker, All Rights Reserved. No portion of this page may be duplicated or distributed without the author's written consent.)
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