What gives the sitar its characteristic sound?

Question

The sitar has an instantly recognisable sound:

http://soundcloud.com/georgeharrison/your-eyes-sitar-solo

I've always assumed that the characteristic 'lush background drone' that I associate with the sitar came from its sympathetic strings resonating with the plucked string.

But on Friday night when I went to hear the amazing Lady Maisery at the Cambridge Folk Club their violinist and banjo player, Rowan Rheingans, played one piece on what she called the bansitar, a cross between a banjo and a sitar.

The piece is Nottamun Fair on their first CD, Weave and Spin.

The bansitar Rowan plays is invented and made by her dad, Helmut Rheingans, and I emailed him to find out more. One thing that surprised me was in this comment (my emphasis):

The BanSitar has only 5 strings, no sympathetic strings, as did the original persian sitars (si tar meaning Three strings), the sympathetic strings where a 19th century addition, when steel strings where invented.

So his bansitar does not have sympathetic strings and yet it clearly has the sound I think of as characteristically sitar-like. What gives the sitar its characteristic sound?

Answer 1

In fact, the whole of Sitar brings up that sound! Seven main components that contribute to the quality of the sound can be identified as follows. To note, there are two bridges, not one, and there are three classes of strings, not two!

(1) Ghodi (the primary bridge): its curves and finish (2) Tumbaa (Pumpkin shells as Resonators): a second resonator at the upper end can enhance the sound, but it makes the sitar a bit heavier to balance (3) Mizrab (Striker) (4) Tarafs (resonating strings, or we can refer to them as tertiary strings) (5) Secondary bridge used for the resonating strings, (6) Primary Strings, and (7) Chikari Strings (Secondary strings), with them the main strings share the main bridge.

The sound quality changes upon variations in these.

Answer 2

Sadly I think this may be a duplicate of the question Altering the sound of a guitar to match a sitar.

But before this question is closed as a duplicate I want to nip in with an answer I just got over email from Helmut

Most people think that the sound is created by the sympathetic strings, but it isn't. It's the bridge, a wide, slightly curved piece of bone upon which the strings bounce off, that is responsible for the sitar sound. Sympathetic strings merely enhance the sound, add depth and colour, as they do with viola d'amore, nyckelharpa etc.

Wheat's answer to the other question covers both the sympathetic strings and the sitar-like bridge added to guitars to make them sound like sitars, and Kevin's answer even mentions the bansitar.