The tabla achieves near-harmonic modes through membrane density variation

Evidence

The boundary around which the membrane is stretched is the analog of the two points between which a string is stretched. With a few notable exceptions (the tabla for example manages a more harmonic relation of its modes by membrane density variations), almost all instruments use a membrane uniformly stretched in all directions and uniform in thickness (mass density). The equations and the solutions governing the motion and modes of such a membrane are well-known. — Eric J. Heller, Why You Hear What You Hear- An…, 1358

Categorization

• XREF: The tabla exception is a striking counterexample relevant to how instrument design manipulates partials for musicality — ties into why some drums sound pitched and others don’t. — connects to: Drum membrane modes are not harmonically related — Eric J. Heller, Why You Hear What You Hear- An…, 1357; Drum membranes always have one clamped-edge circular node
• SHARE: A tabla player or percussion acoustics nerd would appreciate this density-variation trick for achieving harmonic modes on a membrane.
• corroborated: 2 independent passages support this claim — Eric J. Heller, Why You Hear What You Hear- An…, 1358