Positioning the bridge

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StVitus
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Positioning the bridge

Postby StVitus » Mon Apr 17, 2017 5:11 am

Forgive me if it seems like I’m asking questions I already know the answers to, but I need confirmation before I keep going so I don’t flush an afternoon down the toilet.

After giving my new sitar a setup it’s clear the bridge is in the wrong spot. Many frets were flat at their old locations and have to be moved with the string against the frets to intonate. Some of them would need the strings to pass through the pegs to be in tune. This means I need to move the bridge toward the tailpiece, correct? On my other sitar, which it set up properly, the nut-to-bridge distance is 1cm longer. Would that be a good starting distance for this one?

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Sitarfixer
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Re: Positioning the bridge

Postby Sitarfixer » Mon Apr 17, 2017 6:11 am

Your enthusiasm and drive regarding setting up a sitar is admirable. Your lack of experience or fear of the unknown is making me nervous. To get the bridge where it's supposed to be is a juggling act of sorts. First up - center the frets between the taraf pegs. Anticipate fret #14 (Dha) shifting down the 1/2 step to komal Dha without it colliding with a peg shaft. The frets need to be set up as such. Fret 18 is even more touchy for high komal Re. Tune the strings. "Bell tap" the center of the 1st. string. You need to hear a clear overtone octave note of the open string "Ma". Play "Ma" on the 11th. fret. If the note is a good "Ma" your bridge is likely to be in a good position. If the fretted note is higher than the bell tone, the bridge is too close to the frets. If the fretted note is lower than the bell tone, the bridge is too close to the tail piece. Adjust accordingly in 1/4" intervals until the bell tone "Ma" is the same as a fretted "Ma". Retune all the strings as string tension will diddle the neck a bit. Fretted "Ma" will be an octave below the bell tone. Check fret 17 ( high Sa ). Adjust accordingly. Fine tune the remaining frets. Having them exactly between the peg shafts allows margin for fine tuning once the bridge is set right with the bell tone. That note is the key. You'll get the hang of it. Hey ! I did ! Have fun ! ! !

StVitus
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Re: Positioning the bridge

Postby StVitus » Mon Apr 17, 2017 7:01 am

Thanks, Tony. I’ve been doing my own guitar setups for years so sitar isn’t too hard for me most of the time. I’ve tried moving the bridge in each direction and I’m still not getting the ma harmonic close to being in tune. This instrument probably went twenty years without a full set of strings, so I think the neck might be bowing back and forth as it adjusts to tension. I brought it up to tension over two days, but that might not have been enough time. I’m going to just leave it in the case for a few days to see how it does after the neck has had time to settle.

barend
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Re: Positioning the bridge

Postby barend » Mon Apr 17, 2017 9:04 am

Sitarfixer wrote: "Bell tap" the center of the 1st. string. You need to hear a clear overtone octave note of the open string "Ma". Play "Ma" on the 11th. fret. If the note is a good "Ma" your bridge is likely to be in a good position. If the fretted note is higher than the bell tone, the bridge is too close to the frets. If the fretted note is lower than the bell tone, the bridge is too close to the tail piece. Adjust accordingly in 1/4" intervals until the bell tone "Ma" is the same as a fretted "Ma"


Are you saying the Ma harmonic (halfway string length) should be EXACTLY above the Ma fret (like on a guitar)? On almost every sitar that I played the Ma harmonic is not exactly above the fret. Most of the times the harmonic is a bit to the right (from players perspective.) Somewhere between Ma and tivra Ma.

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Re: Positioning the bridge

Postby Sitarfixer » Mon Apr 17, 2017 6:05 pm

Exactly, Barend. Prime contact point would be just right of the fret. Pressing the string down to the fret raises that strings tension, which for intonation purposes is compensated by the frets shifted to the left as needed to produce an in tune note. Truely a nit picky detail point but there it is - addressed in full. The higher the string action, the more the difference between the physical string center point and fret point becomes. " Doo Daah Doo Daah " ! ! ! 8)

StVitus
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Re: Positioning the bridge

Postby StVitus » Wed Apr 19, 2017 9:03 pm

I’m still having trouble with this. I can get the ma fret to match the harmonic. But they’re still both flat. What do I do to get them in tune?

I’m tuning the guitar so that it’s in tune at the Sa fret, seventh fret. Then I’m trying to get the bridge and ma in tune. Should I be tuning so that ma is in tune, moving the bridge to fit the harmonic to ma, and then adjusting the other frets?

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Re: Positioning the bridge

Postby Sitarfixer » Thu Apr 20, 2017 2:15 am

Frets centered between the pegs - priority 1; class A compulsory directive; you must comply.

Get the bridge where you think it looks good or matches original placement marks on the tabli - pretty much in the middle of the sound board.

Tune that 1st. open string to MA.

Bell tap that string at fret #11 ( and slightly more toward the bridge ).

Play the fretted MA on that string.

Fretted note lower in pitch than the bell tone MA - move the bridge closer to the frets. ( 1/4" +- increments ). Keep diddling this move until the bell tone MA is the same as the fretted MA.

Fretted note higher in pitch than the bell tone MA - move the bridge AWAY from the frets. ( 1/4" +- increments ). Keep diddling this move until the bell tone MA is the same as the fretted MA.

Tune all the strings and repeat this shifting process until you've got all good notes on all the frets. Fine tune the frets after the string / bridge shuffle is over.

Follow these steps in this order and you should have it running proud and proper.

StVitus
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Re: Positioning the bridge

Postby StVitus » Thu Apr 20, 2017 5:28 am

Thanks again Tony. That fixed the problem in about ten minutes. I was taught to tune so that sa is in tune and I forgot that I couldn’t expect an in tune harmonic for ma if ma was out of tune!

I have one fret—high sa—that ends up slightly sharp because it’s up against a peg. Does it make sense to move the bridge toward the tailpiece slightly so this note is in tune and then adjust the frets again?

barend
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Re: Positioning the bridge

Postby barend » Thu Apr 20, 2017 11:10 am

Sitarfixer wrote:Exactly, Barend. Prime contact point would be just right of the fret. Pressing the string down to the fret raises that strings tension, which for intonation purposes is compensated by the frets shifted to the left as needed to produce an in tune note. Truely a nit picky detail point but there it is - addressed in full. The higher the string action, the more the difference between the physical string center point and fret point becomes. " Doo Daah Doo Daah " ! ! ! 8)


Still not 100% sure what you mean. In your opinion should the Ma harmonic be exactly above the (not pressed down with finger) Ma fret (like on a guitar) or is it ok if the harmonic is a bit more to the right of the Ma fret (from player's perspective)? Just wanna know for sure.

As I said on most sitars I have played the harmonic is located a bit more to the right.

sason
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Re: Positioning the bridge

Postby sason » Thu Apr 20, 2017 7:34 pm

StVitus wrote:
I have one fret—high sa—that ends up slightly sharp because it’s up against a peg. Does it make sense to move the bridge toward the tailpiece slightly so this note is in tune and then adjust the frets again?

Yes.

I just wanted to add that after you check the MA fret and before doing any adjustment, it is better to check the high Sa fret in order to see how much you can move the bridge. Any adjustment you make will obviously necessitate re positioning other frets. High Sa and also Ma tivra have a limited area.

I would check the position of frets also with the Jori String.

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Sitarfixer
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Re: Positioning the bridge

Postby Sitarfixer » Fri Apr 21, 2017 1:19 pm

Barend. You're worried about a nit picky detail that has no effect on the tuning topic. The bell tone on that string will be the exact center of the string length from nut to bridge. That's the law ! ! ! The fretted note is arrived at by a combination of shifting frets and positioning the bridge. Bridge shifting changes the string length but whatever that string length is, the bell tone will again be at the exact center of the open string. Retune the string once the bridge has been shifted to your liking. Now play (fret) the MA note (fret #11) and adjust that frets position until you've got a MA that sounds in tune. Check the remaining fretted notes up and down the neck. Here is where you'll need to see if there is any problem with peg shafts being in the way of fret threads. This is why I suggest setting all the frets centered between the pegs so there is comfortable margin to adjust one way or the other as this operation commences. It becomes a bit of a juggling act going back and forth between bridge position, peg location and fret position. String height also comes into play. If the stings on the main bridge are high, it takes more pressure to get them down onto the frets. That raises the strings tension and thus the note heard. Pitch compensation now must be accomplished by shifting the frets away from the bridge. Here your messing with the other factors again. Some fun eh !?!

barend
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Re: Positioning the bridge

Postby barend » Fri Apr 21, 2017 11:16 pm

:D yes I agree with everything you say Tony! You can't expect it to be as precise as a guitar. So you have take into account that these harmonics are always not spot on above the frets when you play them.

Also good point about the action. When you shift the bridge that will come into play. You might have to file down the bridge legs if the action is too high. Not easy to get that right.


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