Q: What difference does the upper tumba make?

A: The upper tumba can be made of a natural gourd or from wood spun on a lathe like a wooden bowl. It adds some volume to the sitar, especially for the bass strings. It easily screws in and out so it can be taken off for transport (i.e if you have a single gourd fiberglass case) or just preference. Most people prefer it on for the balance that it gives the instrument.