Mridhangam is a South Indian Percussion Instrument used for Classical Music Concerts as an accompanying Instrument. It has got two sides viz, the right side and the left side for a normal right handed person. The Mridhangam is made of wood and the wood used are Jack fruit tree wood, Mango tree wood and others. The skin used to prepare the mridhangam is goat skin, cow's skin and buffallo's skin. The right side contains three layers called "Vettu Thattu" (outer layer), "Kottu thattu" (bottom layer) and "Ultharai Thattu" (innermost layer). The first two leathers are visible from outside whereas the bottom layer is not visible from outside. The left side contains two layers. The right side and left side are tied to each other by a thread like buffallo's skin. On the right side there is a black patch made out of a powdered special stone brought from the river beds of Kaveri (a river in Tanjore, Tamil Nadu, India). The black powder (which is manganese oxide basically) is mixed with cooked rice and made into a paste and applied on the place provided for it and polished with polishing stone. The process of applying the paste takes nearly 3 - 4 hours and the repairer then allows it to dry. The paste is applied to the desired level on the Mridhangam according to the Pitch. Later on after the mridhangam has dried, in between the "vettu thattu" and "Kottu thattu" layer on the right hand side he inserts a small piece cut flat broom stick on all the points where the rope meets the "Vettu Thattu" or the outer skin. In other words this stick is placed in between "Vettu Thattu" and "Kottu Thattu" where the leather rope meets the "Vettu Thattu". There are generally 16 such sticks inserted and it produces a nice vibrant sound. This type of inserting sticks are called "Kuchi" type of mridhangam. Some other people use a special type of black grains called "Kappi" (generally looks like the mustard seed)that is inserted in between the top most layer and the bottom layer. This produces a different vibrant sound than the "Kuchi" type of mridhangam. It is only a matter of individual mridhangist's preference that a mridhangam is made either as a "Kuchi" or "Kappi". One caution here the "Moottu" is prepared earlier based on the type of instrument a mridhangist wants. Generally intermingling of "Kuchi" and "Kappi" is not done and moreover after a "Moottu" has been prepared for a particular Naada variety, it is maintained thoroghout the life of the "Moottu", which is normally 3-4 years based on its use and also the number of times the leather rope is tightened or loosend. The life of the "moottu" is also use-based than on time-based. The life span is only arbitrary as it differs from individual to individual based on its proper maintenance.
The left side doesnt produce a bass sound by itself. A paste has to be made out of "Rava" or semolina and is applied to the desired level on it and then only it produces a deep bass effect. There are also other methods adopted to produce the bass effect. They are applying a synthetic material resembling semolina. This material is reusable as compared to Semolina. Semolina paste is removed after the concert is over. One more method is adopted that is some mridhangists apply the black patch to a desired level, as it is being done on the right hand side. This also produces a bass sound. This type was widely used by Mridhangist Shri.T.V.Gopalakrishnan.
The mridhangam varies in size according to the pitch. The size varies from 18 inches to 26 inches. The more the size the lesser the pitch. The pitch is also decided from the circumferance of the mouth of the mridhangam. It varies from 6 1/2 inches to 7 1/4 inches. The more the circumferance the lesser the pitch and the lesser the circumferance the higher the pitch.
The Male range voice generally ranges from a little less than "C" to "D" or in other words, that which is populary in vogue in the Carnatic Music Circles, 3/4 to 2. The female voice generally ranges from "F" to "A#" or in other words 4 to 6 1/2.
The tuning of the mridangam is an art by itself equivalent to learning to play it. It generally comes by years of experience and constant practice. One's ears should be tuned to the tambura as well as the sound emanating from the Mridhangam. Moreover the Instrument is very sensitive and has lot of tuning difficulties. Only a trained person can perfectly tune the instrument and also maintain the pitch from varying, till the end of the concert. Additionally, the mridhangam being a wood instrument, is also sensitive to the climatic conditions. Its behaviour will change according to changes in the weather. Even the slightest weather change affects the instrument drastically. The care of the instrument is a major task for any mridhangist.
