M R I D A N G A M

Mridangam is a Carantic percussion instrument, made of hollow wood, strapped with two sophisticated leathers on both the ends. Construction and compsition is so unqie that the melodious sound produced by the instrument is as close to the human voice. Picture can explain better, when it comes to what and how is it built.

The mridangam is the classical double sided drum of South India and is used as an accompaniment for vocal, instrumental and dance performances. The term mridangam is derived from the sanskrit words “Mrid Ang” which literally means “Clay-Body,” indicating that it was originally made of clay. The present day mridangam is made of a single block of wood. It is made either of Jackwood or Redwood. Jackwood has more fibrous structure than the other types of wood.The packing of the fibres is also very high.The pores present in jackwood is less when compared to others. The pore size and distribution of the material can be inversely proportional to the modulus of the wood.the density of jackwood is also less when compared to other woods.

V = E/P where V=velocity of sound, E=modulus, P=density

Therefore the velocity of sound will be more when the pore size and distribution and density is less. In some cases the core of the coconut or palm tree is also used. It is a barrel-shaped double-headed drum, the right head being smaller than the left. The two heads are made of layers of skin. The heads are stretched by leather straps which run along the sides of the body. The pitch is adjusted by moving small wooden cylindrical pieces of wood between the wooden shell and the leather straps.

The right head is made of three concentric layers of skin. The innermost layer is not visible. The outer ring is called the Meetu thol and the inner ring is called the Chapu thol. The inner ring is made of sheepskin and the outer skin is made of calf-hide. At the center of the right head is a permanent spot of black paste. This spot, called the Soru, is a mixture of boiled rice, manganese and iron filings. This black spot is responsible for the special tone of the mridangam allowing emission of harmonics. Different harmonics of the head are produced by various finger combinations.

The left head, known as the ‘Toppi’ is made of only two layers; the inner one is made of sheepskin and the outer one is made of buffalo hide. Before playing the mridangam, a thick paste made of semolina (sooji) and water is applied to the center of this head. This is done to lower the pitch and produce a bass sound on the left head. This paste is scraped off after the performance. The right head is tuned to the Tonic. On the rims of the two heads there are spaces for the leather braces to pass through. A small, smooth stone and a small stick (wooden) are used to vary the pitch of the heads by upward or downward strokes on the rims. The pitch of the mridangam varies according to its size. The larger the mridangam, the lower the pitch and vice versa. The walls of the instrument are 2/3 centimeters thick and give it stability in the low frequencies. Mridangam uses a single resonator. Therefore the tension of the left and right sides of mridangam are inseperable unlike the Tabla where the tension of the left and right sides are seperate because of the use of two resonators. Mridangam’s single resonator also produces an acoustic coupling between the two heads. There is a hole in this outer covering which exposes the main membrane below. This annular membrane is much more prominent in the mridangam than in the tabla. Pieces of straw are placed between the main membrane and the annular membrane radically between the two skins. This actually increases the dampening and acts as a snare.

Also, the pictures shows the various fingering styles in order to get various melodies.

Mridangam is characterized by a rich and varied tone. Some strokes evoke clear pitched sounds while others evoke unpitched sounds. The following discussion is based upon the pitched strokes because they more clearly show the tonal differences.

The size of the mridangam is one of the important factor for the sound it produces. The pitch of the mridangam varies according to its size. The larger (Fig.1a) the mridangam, the lower the pitch and the smaller (Fig.1b) the mridangam, the higher the pitch.

Rim Stroke (right hand) – The rim stroke is a major stroke on the mridangam. Although the nomenclature varies, this stroke is usually called “Na” in the North and “Nam” in the South. On mridangam a predominant third harmonic is the main characteristic (Fig. 2 a, b; below). However, the fundamental may be seen in significant proportion in the mridangam while it is essentially absent in the tabla. Furthermore the second harmonic tends to be evoked in the tabla while it is suppressed in the mridangam.

Open stroke (right hand) – The open stroke is also a major stroke for both drums. This is called “Tun” in the North and “Dheem” in the South. Both strokes are characterized by a very prominent fundamental. However there is a significant difference in the second harmonic (Fig. 2 c,d).

Open stroke (left hand) – The open stroke of the left hand is called “Ga” in the North and “Thom” in the South. It shows a tremendous difference between the two instruments (fig. 2 e,f). It has been found that the tabla has a very pronounced fundamental and a long sustain. There are much fewer harmonics in this stroke. Conversely the mridangam has a much more complex harmonic spectrum and a significantly reduced sustain.

In order to know the physical and structural relation of the type of skin used in making the instrument and the sound produced, the cross sectional features of leather used in different instruments were studied. In various skins horizontal fibres running predominantly along the scales direction and the network structure flows perpendicular to the scales direction. In goat skins, there is no horizontal running of fibre bundles and the fibres is in loose weaving. In sheep skin, the grain layer is comparatively larger than that of goat skin and fine fibres predominantly running along the hair follicles direction. The cross sections are plain and compact in cow calf leather. The fibres are glued together and from seperate blocks in all directions. The theory of circular membranes considers them as two dimensional stretched strings. The fundamental frequency can be related as :

fo1 = 0.382 T R õ

where, fo1 = fundamental frequency R = radius of the membranes T = circumferential tension/unit length (õ) = mass/unit area of the membrane

The pitch of the membrane, as in a stretched string depends on the size and weight of the membrane and the amount of tension it is under. The pitch lowers, as the size or weight is increased and rises when the tension is increased. In the case of drums, the sound produced by it depends on the resonator column and the properties of leather, the loudness depends on the amplitude, energy and the intensity.

The fingering technique is a very important consideration in a discussion pertaining to mridangam. The mridangam has a balance between the powerful and delicate techniques. A brief look at the history of the instrument shows why.

The evolution of mridangam may be traced to an archetypical mridang. This instrument had a close association to the ancient mythological dramas. This association meant that the drums would sometimes have to support both masculine and feminine characters. The delicate movements of the dance are known as lasya while the more powerful masculine movements are known as tandava. Powerful techniques were developed to accentuate the masculine roles while delicate techniques were developed to support the feminine roles.

In the last several centuries the drumming technique in north Indian music has bifurcated. The more powerful and aggressive techniques have been relegated to the pakhawaj while the delicate techniques have been relegated to tabla. Yet there was no bifurcation of technique in the South. The powerful and aggressive techniques exist alongside the delicate.

The mridangam is played primarily by using the index, middle, ring and small fingers of both hands while the thumb finger is used as a support element. The palm of the right hand is also used mainly while playing the stroke “plam or jham”. To play the strokes “nam” and “dhim”, it should be kept in mind that when the index finger is used to play these strokes, the ring finger should always be positioned in between the outer rim and the inner black ring on the right side of the mridangam (fig.1). The stroke “thi” is played by using the middle, ring and small fingers of the right hand in the centre of the black area on the right side of the mridangam but it should be noted that these three fingers should be held together while playing this stroke. Even while playing the stroke “jham”, these three fingers should be held together. The stroke “ta” is played by using the index finger of the right hand at the centre of the black area on the right side of the mridangam.

Fig. 1

Fig. 2

Mainly two strokes are played on the left side of the mridangam. These are “thom” and “tha”. “Thom” is played by using the middle, ring and small fingers of the left hand and these three fingers should be held together while playing Another technique involved in playing the mridangam is the use of “Gumki”. It is played on the left side of the mridangam and is played instead of playing “Thom”. One can produce subtle and soothing sound using Gumki which is played using the lower part of the palm and the middle and fore fingers of the left hand.this stroke. “Tha” is played by using the four fingers other than the thumb finger and again these four fingers should be held together.