The mridangam is a percussion instrument of ancient origin. It is the primary rhythmic accompaniment in a Carnatic music ensemble. In Dhrupad, a modified version, the pakhawaj, is the primary percussion instrument. A related instrument is the Kendang, played in Maritime Southeast Asia. Its a complex instrument to tune and involves a lot of mathematics to construct korvais. During a percussion ensemble, the mridangam is often accompanied by the ghatam, the kanjira, and the morsing. The mridangam is a double-sided drum whose body is usually made using a hollowed piece of jackfruit wood about an inch thick. The two mouths or apertures of the drum are covered with a goatskin and laced to each other with leather straps along the length of the drum. These straps are put into a state of high tension to stretch out the circular membranes on either side of the hull, allowing them to resonate when struck. These two membranes are dissimilar in diameter to allow for the production of both bass and treble sounds from the same drum.