A dilrhuba is played with a violing bow, it has 4 strings, and 20 resonance strings, enge, samt 20 resonansstrenge. All strings rest on a skin covering the body. It comes from india and is capable of playing in steps of quart tunes, as used in India, but rather unknown in the west. It is untuned, as the resonance strings would mix up in every discussion in the room where the dilrhuba is stored.    
Arrangement of the strings, below the resonance strings.

So it works:

When a string is bowed, it swings (1). Putting a finger on the fingerboard (2), lets the string appear shorter, and the tone becomes higher.


Other informations
Made by: Unknown
Made in: India 1980
Materials: Wooden body, skin, metalstrings.
Condition: Ready for use, not tuned