The Tabolin is an experimental violin, part of a series of Off-Beat Fiddles https://www.andrewcarruthers.com/off-beat-violins/. It has the basic form of a violin with the addition of velum, drum like, panels. The panels can be given a tuned, sustained pitch by adding weights to them. in this they resemble the Indian Tabla drum, Hence the instrument's name "Tabolin".
It was hoped that the tuned panels might cause sustained sympathetic vibrations, similar to the sympathetic strings on a viola d'amore or a Hardanger Fiddle
More about the Tabolin https://www.andrewcarruthers.com/?s=tabolin
In this video my friends Gabriel Wheaton @theredfiddler, and Joe Peterson take the fiddle for its first test.