Pitch and timbre determination of the angklung

American Journal of Applied Sciences, Jan, 2009 by Mohd Ridzuwary Mohd Zainal, Salina Abdul Samad, Aini Hussain, Che Husna Azhari

INTRODUCTION

An angklung is a rattle like musical instrument that is made entirely from bamboo. The angklung sound is produced from an impact mechanism within its body structure without the use of any tensed strings or stretched membranes. Therefore, the angklung is classified as a percussion musical instrument of the group idiophone along with the xylophone and the gong. Figure 1 shows the front view of the angklung.

[FIGURE 1 OMITTED]

The angklung is generally supposed to originate from West Java. According to folklore, angklung was a musical instrument of agricultural festivals and was also used during the festivities to arouse the fighting spirits of soldiers. It was also associated in Java with hobby-horse dancing (1), (2). In the 1920s, it was used as children's toy and then in the 1930s, it was used by beggars to attract passers by. Daeng Sutigna of Bandung, a musician, then started to resurrect and popularise the angklung. He introduced tunes similar to Western music, composed modern arrangements and recruited more angklung enthusiasts. Angklungs normally found nowadays are tuned to the Western diatonic scale which differs from the traditional pentatonic scale (3).

Three species of bamboo have been reported to be used in angklung production. The first is the bambu tutul or Bambusa vulgaris Schrad. ex J.C. Wendl. var. maculata Widjaja. However, recently this type of bamboo is rarely used for the angklung. The second species is the bambu hitam or Gigantochloa aff. atter (Hassk.) Kurz ex Munro, which has a distinct leaf anatomy from the true G. atter or bambu temen. This second species is the most used for Sundanese bamboo musical instruments including the angklung. The third species is the bambu apus or Gigantochloa apus Bl. ex Schultes f., which is less favorable because its tubes are not straight and the nodes has little swellings that cause some disturbance in the sound it produces (3).

The angklung's physical parameters and sound is analyzed in this research. Analyzing the angklung is important to recognize the main characteristics that make up the unique sound of the angklung. This will help to make the instrument more accessible and easily utilized in the modern digital music scene. This research will describe how the pitch of an angklung can be determined using physical measurements of the angklung. The length and diameter of the angklung rattle air column are used to calculate the angklung's pitch. This research will also examine the timbre of an angklung and determine the main characteristics that distinguish sound of the angklung from other instruments.

MATERIALS AND METHODS

Every component of an angklung may have its traditional name, but in this research, these components will be given a descriptive name. An angklung has two main parts, the frame and the rattle tubes as shown in Fig. 1. The frame's functions are to hold the rattle tubes and as a place for an angklung player to hold the angklung.

The rattle tubes are the main sound generators for an angklung. The tubes are made from a segment of a bamboo with one of its ends still closed by its node. Part of the segment near the open end of the tube is removed forming the tongue of the rattle tube. A pair of small protuberances is left at the closed end of the tube which we will call tines. These rattle tubes are suspended vertically in the angklung frame. The tubes are suspended in such a way that the tines can slide easily and loosely inside slits made in the bottom frame tube. The bottom frame tube is also made from a bamboo segment but both its ends are open. Figure 2 shows the rattle tube of an angklung (4).

[FIGURE 2 OMITTED]

The angklung is played by holding the frame with one hand and shaking the bottom frame tube sideways with the other hand. This sideways motion will cause the rattle tubes to swing and the tines will strike the end of their respective slits. The angklung can also be played with the frame tilted sideways to shake it just once. Note that each angklung is made to produce just one musical note. Therefore, a whole ensemble of angklung players is needed to play any particular melody. Nevertheless, it is possible to play a melody with just a single player by using a device that holds multiple angklung and allows the player to play all of them by himself.

Tuning of an angklung mainly depends on two measurements, the length of the air resonator and the length of the tongue of the rattle tubes. The air resonator acts like an amplifier in that it amplifies the frequency of sound that matches the natural frequency of the air vibrating inside the resonator. The length of the tongue determines the natural frequency of the whole rattle tube vibration. Generally, the longer the whole rattle tube, the lower the pitch of the generated sound. The rattle tube can be fine tuned by carving parts of the tongue. Sharpening or raising the pitch can be achieved by shortening the tongue at its end. Flattening or lowering the pitch can be done by carving away the part where the tongue and the air resonator meet, thus making the effective tongue length slightly longer.