Karunya Musicals was founded in the year 2014 with a vision to manufacture a new line of ‘synthetic’ Indian percussion instruments,beginning with the launch of the South Indian Mrudanga, followed by Tabla. The primary objective was to bring into fore percussion instruments that are ethical and made using engineering materials that standardize and maintain consistency in tonal performance. The current product offerings include the Synthetic Rhythm Indian (S.R.I) Mrudanga and Tabla made of synthetic drum heads, mounted on fiberglass shells. The synthetic drum head completely avoids the use of animal skins and the sturdy fiberglass shell avoids the need to cut precious trees.

Indian percussion instruments such as the Mrudanga, Tabla, Phakwaj, Khol, etc., produce harmonic overtones, a phenomenon which was first described by Sir C.V. Raman in considerable detail. A seminal paper on this was published by Prof. B.S. Ramakrishna who proved that appropriately loaded circularly symmetric membranes indeed produce harmonic overtones.

The creator of this path breaking instrument is Dr. K. Varadarangan, a Karnatic vocalist,musicologist, physicist, and a wireless specialist by profession having more than 20 years of experience in the industry. This product is the result of his incredible passion, ingenuity, and hard work spanning a period of about five years.

Before we answer the question, let us first look at how the traditional hide Mrudanga is constructed:

The traditional hide Mrudanga is constructed using a hollow shell carved out of a single piece of Jack or any other suitable wood.The right head consists of three membranous coverings as shown in the figure.The inner most covering is in the form an annual ring with its inner edge slightly projecting into the opening. Made of goat skin, this layer serves to protect the main membrane from wear and tear due to friction with the bearing edge of the drum.The middle membrane is the main vibrating membrane, also made of goat skin.

To the central portion of this layer, a permanent black paste made of a dense material is applied, known as the Karane. The Karane’s constitution has been proprietary with different makers using different formulations. Broadly speaking, the paste consists of boiled rice withheavy particles, such as iron oxide or manganese, added to increase the density. Since the bonding of the paste to the skin is mainly through the starch acting as glue, the particles of the Karane wither away over time and the paste needs to be applied every now and then.

The outermost membrane made of cow skin has a circular cutout larger than the Karane. All the layers are braided together at their outer edges and fastened to a leather hoop known as the Indige,which is made of buffalo skin. Small pieces of broom stick(Kannada: HanchiKaddi) are placed around the inner edge between the outer and middle head. Tension is applied to the head by means of a long leather thong made of buffalo skin that weaves back and forth (normally 16 times)between the top and bottom of the drum holding the two heads together.

Cross sectional view of a traditional nut-bolt Mrudanga

More recent versions include threaded hooks attached to the Indige through its eyelets and tightened at the other end using nuts that press against permanently attached metal lugs, thereby creating the required tension.

The left head consists of generally three membranes. The innermost membrane is made of goat skin. Two thick layers of buffalo skin, each having large equi-diameter cutouts, constitute the outer layers. All the layers are braidedtogether at their outer edges and fastened to a circular leatherhoop that in turn attaches to the leather thongs (or hooks). The innermost layer is the vibrating membrane to which semolina paste is applied just before playing to bring down the overall pitch. It may be noted that the left head does not produce pitched sounds.

In fact, the two outer skins press against the inner most skin preventing it from producing a pitched sound, referred to as ringing. The tension of the left head (the innermost vibrating membrane) cannot be varied and the pitch can only be lowered by applying semolina paste. The outer layers offer rigidity to the left side and the Mrudanga can be stored upright with the left head placed on ground. The head produces unpitched bass sounds and facilitates playing of the “Gumkis”.

Now, let us see how the S.R.I Mrudanga is constructed.Broadly, the S.R.I. Mrudanga resembles the conventional“Kucchi”type of the hide Mrudanga except that it is completely synthetic. The right head consists of three layers of synthetic material serving the same purposes as in the traditional hide Mrudanga. The middle layer has the loaded portioncalled the Karane,which is an elastomeric material bonded to the vibrating membrane through a chemical bonding process. It is this Karane that imparts to it the characteristic tone of the Mrudanga. Below this is a layer in the form of an annular ring.

This layer is not visible but serves the purpose of protecting the main membrane from wear and tear. The top most layeris in the form of a circular disc with a circular cutout slightly larger than the Karane.When the head is assembled, the Karane projects out of this cutout. To emulate the Kucchis, special synthetic strips are bonded to the inside of the top layer. These strips produce the typical “Chapu” sound of the Mrudanga.

The left side consists of the same layers as in the conventional Mrudanga but with two improvements.An additional inner layer in the form of an annular ring is used to protect the main membrane from wear and tear. Also, the semolina paste is completely eliminated. The required loading to lower the pitch is provided inside the layer so that the entire playing area is available, which greatly enhances the ease of playing the left hand strokes and the Gumkis. The left side head is covered by a plastic casing that is specially profiled to facilitate easy gliding of the hand during Gumki playing.

Each drum head is provided with a set of 16 metallic clamps that are used to attach and tune the drum head to the shell. The tuning is accomplished using a spanner provided with the instrument. The heads are fully detachable and can be replaced by the user. Detailed instructionson how to attach and tune the drumhead is given separately. Once a new head is placed, it should always be kept under proper tension.The head should never be removed once attached to the shell and must be used till the end of life of the head.

A newly attached head will take about 4-5 days to settle and after the settlingperiod, the instruments can be used to play at concerts. The drum head should be kept in tension during the settling period and readjusted to the original tension once or twice daily. The tuning instructions must be meticulously followed to avoid detuning

Component parts of the S.R.I Mrudanga

The shell is made of fiberglass and a set of 16 lugs are attached on each side of the shell. The bolts pass through the holes provided on the drum head clamps and through the holes provided on the lugs, and the head is held in place and tightened using the long nuts. The shell material is chosen to provide negligible pitch variation due to temperature variations. This was one of the key problems that needed to be solved in creating this instrument. The lugs are fixed to the shell from the inside using bolts. To prevent the rotation of the lugs during tensioning, the lugs are recessed into the shell in a groove-like arrangement.

The drum head clamps and other hardware are completely covered using side covers, thereby giving an aesthetic look, and complete protection to the hands and fingers. The head is tensioned uniformly with the help of the long nuts using a single spanner. A challenge here was to prevent the rotation of the bolts while tightening or loosening the long nuts. This problem was solved using square head bolts and carefully designed drum head clamps.

Fully assembled S.R.I. Mrudanga

One of the distinctive features of this design is the neat seating of the tuning hardware. In a conventional nut-bolt Mrudanga, the hooks project out of the shell and may also cause injury to the fingers of the player. In the S.R.I Mrudanga, the tuning hardware is concealed, leaving access to only those parts that need it.

In contrast to the tuning system of western drums that use a hoop system for attaching and tensioning a drum head, the S.R.I Mrudanga uses a set of 16 metallic clamps on the drum head. The reason for this is as follows:

The rim stroke (Nam or Meetu syllable) is a very important stroke in the case of the Mrudanga. In a conventional Mrudanga, there are 16 points on the rim through which leather thongs run back and forth between the left and right heads to hold them together and provide tension to the head. In the case of the nut-bolt Mrudanga too there are sixteen hooks on each head that are tightened using the nuts. In the case of the western drums, a very precise adjustment of the pitches at various points on the rim is not necessary whereas it is required to be extremely precise in the case of the Mrudanga.

The problem with the hoop system is that when a tension rod is adjusted for pitch at a given location, it will alter the pitches at all other points on the rim as well. This makes perfect tuning a near impossible task.

In the case of the S.R.I Mrudanga, each drum head has 16 metallic clamps. On the right head, the pitch at each lug point (a lug point is the area on the rim of the drum head directly above or below a lug) depends mostly on the tension of the corresponding bolt and does not significantly vary when the tension is altered at some other lug, provided that the variation is not too large.This enables easy tuning and it is not difficult to achieve a tuning accuracy of ±1 Hz at each point on the rim.

The 16 points of tuning provide equal tensioning. When all the lug points are aligned in pitch, the instrument resonates beautifully.Western drums usually have fewer number of lugs because the tension of the drum head is distributed to the lugs by the hoop. The Mrudangas are typically tuned to higher pitches and the 16 lugs help withstand this tension by distributing it among them. So these lugs help in load distribution, equal and precise tensioning, and in achieving excellent resonance.