Nut/Bridge Setup-Sharp at 1st fret.

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Nut/Bridge Setup-Sharp at 1st fret.

Postby HD-Luers » Sat Dec 23, 2017 11:58 pm

So, I have a beautiful Vintage Folkcraft that just got after playing one of Dave's student model's for a couple of years. The folkcraft needed a new nut and bridge. Bought 2 pairs from folkcraft. One to have as a back up in case I screwed up. They are the more expensive ones, forget the name but the simulated bone already pre cut like the drenlin ones. Anyhow, I know I went slow going back and forth got it so that it's a dime at the first fret but along the way I noticed it was very sharp on all strings and it still stayed sharp it's a nickle at the 7th fret. I kept going until I went about as low as I could go and was expecting them to come into tune, but they never did. There is no zero fret on this, it's still sharp 4 or 6 lines on my tuner?

It doesn't sound bad which I don't understand and the 2nd, 3rd, and rest of the frets are all in tune. I expected it to come in tune when it got lower, but it never did. So I don't understand. My VSL is 26 3/4 and I'm using the same strings as I did on Dave's, which did have a slightly lower VSL. I am wondering if that is all that it is. That'll be my next thing to try, but didn't have any to try. Thank you kindly.
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby KenH » Sun Dec 24, 2017 10:32 am

Strings should not affect what you're experiencing.

Are you saying its sharp ONLY on the first fret? Or sharp all the way down?

If everything is sharp, then the problem may be that the actual VSL changed a hair when you removed the old nut & bridge. A few millimeters can make huge difference. Look at the nut and bridge. They are wedge shaped in cross section, right? If there is one vertical side and one angles side, the flat sides need to be facing each other. Measure accurately between the inside edge of the tip of the nut to the inside edge of the tip of the bridge. If it is not precisely 26.75", that could well be the problem.

Are both the nut and bridge set in slots cut across the fretboard? Are the new nut & bridge tight fitting? If not, you may be able to adjust their position just a bit, which could help.
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby dholeton » Sun Dec 24, 2017 11:23 am

Going along with what Ken said and assuming all frets are sharp, attached is a picture of the bridge on my scheitholt. I cut the slot for the bone a little wider than the bone. If you look closely, you might see a thin piece of aluminum in front of the bone to move the bridge farther away from the nut. It's not much, but it brought the scheitholt in true tuning on all frets. If your bridge needs to be farther away, this might be an option. Anything that is hard (metal, wood, bone, plastic) should be okay for making a shim.

Good luck and Merry Christmas

Dave
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Scheitholt_20170524_Final-15.jpg
Bridge cut wider than bone to allow for adjustment
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby HD-Luers » Sun Dec 24, 2017 1:05 pm

It is sharp primary at the first fret on all 3 strings by 4 or 6 cents. 3rd fret and above they are all perfect.
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby dholeton » Sun Dec 24, 2017 1:29 pm

Then the first fret might need to be moved. You might also be able to use less pressure so the string isn't pulled tighter as you press down. 4 to 6 cents on one fret might not be noticed by most people.

Dave
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby KenH » Sun Dec 24, 2017 1:33 pm

What Dave said... moving the first fret that tiny of amount would be a royal witch! Most people won't hear 4-6 cents. A little easier down pressure will help.
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby HD-Luers » Sun Dec 24, 2017 3:09 pm

Thank you all. I did realize one thing. I lightly sanded one and made a slight down angle on it rather than the cut slots and it helped some. Its still a hair sharp but not by much. It sounds and plays better. I guess I thought the slots were supposed to go on both ends.
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby HD-Luers » Sun Dec 24, 2017 4:17 pm

Merry Christmas and Thank You very kindly all
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby KenH » Sun Dec 24, 2017 4:23 pm

Ah so deska! When altering the action (or replacing bridge/nut) you only ever sand the bottom of the nut/bridge, never the top, to adjust the action height!
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Re: Nut/Bridge Setup-Sharp at 1st fret.

Postby Jim Hedman » Sun Mar 11, 2018 7:33 am

I guess the first question that come to mind is "was the intonation correct with the original nut and bridge?" If you did not check it as received you should probably assume the intonation was off to begin with. If the intonation was initially correct I'd carefully check to see if your current nut and bridge might be reversed. Typically a nut with no "zero fret" will slope slightly toward the tuning keys and a fixed bridge will slope slightly toward the tail piece. This assures that the vibrating strings bear directly on the inside edges of the nut and bridge. If the nut and bridge are reversed, such that the misplaced bridge and nut slope downward toward the fret-board, effectively the vibrating string length (VSL) is increased AND ALSO the nut to fret intervals are increased. I would expect that there would be string buzz if this were the case.

Considering a bridge setback alone (assuming a correctly placed nut),the effect of increasing the VSL relative to the fret intervals would cause the intonation to go progressively flat as you moved up the keyboard. To understand this just consider fret #7: the VSL at this fret should be one-half the open-string VSL but a set-back bridge makes fret #7 short of the mark, thus making its VLS longer than one half which causes a lower pitch than desired.

Considering a nut setback alone (assuming a correctly placed bridge relative to fret #7), the effect will be abnormal flatness at fret #1 with progressive improvement as you move up the keyboard (i.e. the intonations sharpen as you move toward an octave).

Obviously nut and/or bridge INSETS will have the opposite effect of OUTSETS. Moving up the fret-board an inset bridge alone will cause the intonation to progressively sharpen while an inset nut alone will cause sharpness at the first fret which progressively improves up the scale.

I had a setup issue with a used dulcimer I purchased that turned out to have an outset bridge and an inset nut. Now that was one pickle to sort out. As in your case I was dealing with a fixed bone bridge and a bone nut with no zero fret. I ended up filling the bridge slot with a piece of walnut fitted such that it was flush with the top of its walnut fingerboard, then fashioned a floating knife-edged floating bridge of walnut. Once I found the correct placement of the bridge relative to the intonation at the seventh fret I got some improvement but it was garishly sharp at the lower frets. I located a fret spacing calculator (http://www.liutaiomottola.com/formulae/fret.htm#mozTocId169477) which confirmed my suspicion of significant nut inset so I replaced the flat topped bone nut with a knife edged walnut nut which effectively decreased the amount of inset. Of course I then had to readjust the floating bridge to compensate for the now increased VSL. Viola! Not perfect but definitely very close. Actually, multiply this effort by two - it was a courting dulcimer! Both fret-boards suffered the same defect.

Since your issue is sharpness it bears mention that excessive string height above the fingerboard (i.e. poor action) can cause this because you are in effect stretching (tightening) the string when fretting. I bought a pretty nifty looking used dulcimer that had very poor action and fretted sharp. I ended up reducing the fixed bridge height by about half and was blown away over how good the intonation was when that flaw was dealt with. It stands to reason string height at the nut can be an issue too but more-so in terms of play-ability than intonation.

In closing from what you describe I'm suspecting an inset nut. If you use the fret spacing calculator to check this out, bear in mind the calculator is designed for a chromatic instrument like a guitar, so each "fret" is actually a semitone. Use the chart below to "convert".

Dulcimer..Guitar Fret
Fret.......(Semitone)
1...........2
2...........4
3...........5
4...........7
5...........9
6..........10
6+.........11
7..........12
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