Selecting different materials would not change much. Call the frequencies \lambda_1, \lambda_2, \lambda_3...

You can prove that changing the material has no effect on the relative frequencies: \lambda_2 / \lambda_1, \lambda_3 / \lambda_1, etc. are completely independent of the material.

The shape is the determining factor; changing the materials (and hence the wave speed) just dilates the whole spectrum.

There's actually a "ring-out" slider and a "mallet" width slider under the drum already.

Ring out controls how fast the higher modes decay (basically stiff vs soft material), The mallet width controls how many modes a strike can even reach, since a real mallet can't drive the high frequency ones very hard.

No labeled presets like "wood" or "metal" though, just raw sliders. Would be a fun addition if someone wants to map a few physically sensible combos to buttons. PRs Welcome!