University of Tsukuba
Abstract :
Tuning of membranophones is important to design timbre, while it is
difficult for inexperienced
players, due to the insufficient ability for judgment of pitch difference.
In this paper, we propose
tuning scheme for membranophones, substituting visual information
for auditory information. First,
vibration modes shape of the head membrane are visualized, based
on the measurement of sound
pressure on the head membrane by a circular microphone array, and
we estimate the tension
distribution of the head membrane, especially unbalance in tightness
of the pair of rods on
oppositional position, make the nodal line of the (1,1) vibration mode
change. Second, we propose a
tuning scheme for membranophones based on information on the
state of the nodal lines of the mode
shapes, visualized based on the microphone measurements, and the
difference of eigenfrequencies
between the orthogonal modes. We show that the proposed scheme
is helpful to make the head
tension uniform, as the results of experiments using the vibration of
tom-tom with only one side head
stretched as an example of actual membranophones. We expect this
scheme to train the tuning
ability for inexperienced players.