Mridangam is a double-sided percussion instrument used in South Indian classical music concerts as an accompaniment. It consists of a smaller, centrally loaded membrane on the right and a larger membrane on the left. These are assembled on a wooden shell which encloses an approximate double-conical acoustic cavity. In this paper, the effect of the shape of the cavity on the music generated is of interest. For this purpose, a one-dimensional analytical model based on a diverging-converging conical horn with short cylindrical ends is developed. The first six axial natural frequencies and modes are computed from this model and validated using a 3D finite element model. Moderate alterations to the geometry of the horn show a marginal shift for the first mode and almost no significant change at the higher modes. However, cavity response to boundary excitations for different shapes reveals a possible impact on the vibro-acoustics. © 2019 Proceedings of the International Congress on Acoustics. All rights reserved.