How can we differentiate aurally between the mridangam and tabla?

There are a number of differences between the construction of mridangam and tabla. Some of the differences are obvious and some are more subtle.

The most obvious difference in construction is that mridangam uses a single resonator while the tabla uses two. Therefore the tension of the left and right sides of tabla are separately controlled, while they are inseparably linked in mridangam. Mridangam's single resonator also produces an acoustic coupling between the two heads (Bhat 1991).

The drumheads show major differences. For instance the mridangam is made of extremely heavy hides while the tabla uses thinner ones. The left hand tabla has a permanent dry application while the mridangam has a temporary wet application of flour and water. Both drums have a skin that does not completely cover the surface (Courtney 1988). 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.

There are items placed between the main membrane and the annular membrane that further accentuate these differences. Tabla often has a string placed between the annular covering and the main skin, while mridangam has straw. This may not appear to be a significant difference but the purpose of these insertions is diametrically opposite. String is placed in the tabla to lift the annular membrane and reduce the dampening effect. However the mridangam has pieces of straw placed radially between the two skins. This actually increases the dampening and acts as a snare. The cumulative effects of these differences in construction create major differences in the tone of the instrument (Rossing 1992).

Tone

Both tabla and mridangam are characterized by a rich and varied tone. Some strokes evoke clear pitched sounds while others evoke unpitched sounds. We will concentrate our discussion upon the pitched strokes because they more clearly show the tonal differences (Courtney 1991).

Rim Stroke (right hand) - The rim stroke is a major stroke on both the tabla and the mridangam. Although the nomenclature varies this stroke is usually called "Na" in the North and "Nam" in the South. On both instruments a predominant third harmonic is the main characteristic (Fig. 2 a,b; below). However, the fundamental may be seen in significant proportion in the mridang 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 mrindgam