Bridge and Nut fix question
Instruments- discuss specific features, luthiers, instrument problems & questions
traildad:
Strumelia:
You tune it so it's not sharp. You tune all your open strings to be in tune.
How does that work? Tune them while fretted? Wouldn’t that cause it to be flat when unfreted? If they’re stretched different amounts I can’t see how they would make the same note. Maybe it wouldn’t be enough to notice depending on the difference in height off the fretboard. Isn’t it customary to set the action for all strings to the same height?
As I wrote, tune the open strings to be in tune.
A couple of basic concepts here are:
1) the mere act of tuning = stretching the string to various tensions, causing the note to go higher or lower. If an open string is out of tune, you turn the pegs and tune it to be in tune. Just because a nut notch is higher or lower than the one next to it won't doom an open string to be out of tune by nature.
2) as to fretted strings: if a bridge/nut is very tall and makes the string action too high off the frets, then fretting the string can push down the string enough of a distance to cause a slight bend in the string and pull it a fretted note a little sharp. A 32nd of an inch slot height difference is not likely to do this enough to be able to hear it, especially while playing tunes.
Notches have two jobs: to keep the strings securely spaced from each other from side to side, and to hold the strings at a good height above the frets (action) so that playing will be comfortable for the way you play and so there won't be buzzing if the action is too low. Most folks like as low an action as possible without buzzing (especially beginners with hurting fingers), but there are good reasons why other folks might want slightly higher action. Too high an action causes problems too. Most people agree that dulcimer string notches should be of uniform action height, since there's no reason to purposely make them different heights.
The tiny amount of difference between notches in your photo of notches is probably not going to cause discernable out of tune-ness when playing. If a notch is a tiny bit too low though, it might cause fret buzzing, depending on the action height.
3) Assuming a reasonable action height for all strings, if the frets are in the right places, your fretted notes will sound generally in tune if the open string is in tune.
Overall, it's common that people wind up buying used dulcimers that have had prior owners file nut and bridge slots to various heights and widths over time. Maybe they put on heavier strings at some point and widened the slots. Two of those U slots in your picture look way too wide for that string shown. Over time or with changing playing preferences, people can change their mind about action height they prefer, or string spacings. It's not uncommon for nuts and bridges to accumulate notch adjustments over time until the best option is to put in a new nut and/or bridge and start fresh, since nuts are cheap and it's usually a simple procedure. A good guitar luthier should have no trouble doing it right, and the job shouldn't cost a fortune.
updated by @strumelia: 11/17/20 03:17:36PM