What makes strings go sharp?

[sykofiddle]

I have a vintage A2Z with the original tuners. I notice that when I tune by the time I've gone through all the courses some have gone sharp 2-4 cents. I'm used to things going flat as strings stretch but sharp is another story. Sometimes I can hear it happening in real time as if the string is "missing" the correct tension and jumping from slightly flat to slightly sharp.

I will be having the tuners replaced with Rubners and I suspect this will help but I'm still curious what causes this to happen. Can a sticky nut slot do this? Natural expansion/contraction of the top?

[Tom Ronan]

This happens to me on all my mandolins.I think your right about expansion and contraction.

[Mike Buesseler]

And lubricate nut slots with pencil lead.

[Caberguy]

Sometimes I can hear it happening in real time as if the string is "missing" the correct tension and jumping from slightly flat to slightly sharp.

Yeah, that sounds like the nut is binding. Or maybe the string windings are overlapping and the string is ramping up onto the overlap.

Does not sound like the kind of thing that new tuners would really help with.

(I meant to say doesn't, edited to correct, not the best place for a typo)

[pops1]

No new tuners will not help with this problem. Have someone file the nut slots to match the gauge of the strings, or lightly take the winding bumps out of the slot. It is the string sticking in the slot of the nut or bridge, or both, not the tuners tuning themselves sharper.

[Bill McCall]

I think the added deflection of the top as the strings are brought to pitch plays a role. Easy to see on the G course.

[sykofiddle]

Thanks for the replies. The new tuners are to help with the considerable play in the originals. I hadn't thought of a sticking nut slot being able to make a string go sharp but it makes sense I suppose - if the tuner is increasing tension that is only put into effect when the string unsticks. The other thing (duh - I just realized this...) I put on J74's a month ago and there were 73's on when I acquired the instrument. I'm gonna have a new nut made as well so that should take care of it. Appreciate the input!

[pops1]

You don't need a new nut, just have them cut the slots for the J74's and it will be fine.

[dhergert]

I have a vintage A2Z with the original tuners. I notice that when I tune by the time I've gone through all the courses some have gone sharp 2-4 cents. I'm used to things going flat as strings stretch but sharp is another story. Sometimes I can hear it happening in real time as if the string is "missing" the correct tension and jumping from slightly flat to slightly sharp.

I will be having the tuners replaced with Rubners and I suspect this will help but I'm still curious what causes this to happen. Can a sticky nut slot do this? Natural expansion/contraction of the top?

Thanks for the replies. The new tuners are to help with the considerable play in the originals. I hadn't thought of a sticking nut slot being able to make a string go sharp but it makes sense I suppose - if the tuner is increasing tension that is only put into effect when the string unsticks. The other thing (duh - I just realized this...) I put on J74's a month ago and there were 73's on when I acquired the instrument. I'm gonna have a new nut made as well so that should take care of it. Appreciate the input!

If your mandolin has an adjustable bridge, that can easily be the source of the problem. In order to adjust action higher and lower without binding, the post holes for the adjusters in the saddle have to be slightly oversized, plus they tend to wear into larger holes as adjustment is done. As you tune, one string at a time, the strings progressively pull and cant the saddle forward slightly, sharpening other strings.

In particular some courses are more susceptible to being pulled sharp at the bridge and saddle depending on the order that the string tuning is done. For example, if you tune high to low, the lower wound strings tend to pull the saddle forward more due to friction. Sometimes if I know a certain string has a tendency to be pulled sharp while tuning other strings, I'll tune it slightly low so it will come up to pitch as the other strings are tuned.

This and humidity related expansion/contraction in the mandolin, and temperature related metal expansion/contraction in the strings and tailpiece, make mandolins very challenging to tune. When I am serious about tuning it almost always takes 2 passes of tuning every string, sometimes more.

Good luck with this!

[sykofiddle]

If your mandolin has an adjustable bridge, that can easily be the source of the problem. In order to adjust action higher and lower without binding, the post holes for the adjusters in the saddle have to be slightly oversized, plus they tend to wear into larger holes as adjustment is done. As you tune, one string at a time, the strings progressively pull and cant the saddle forward slightly, sharpening other strings.

In particular some courses are more susceptible to being pulled sharp at the bridge and saddle depending on the order that the string tuning is done. For example, if you tune high to low, the lower wound strings tend to pull the saddle forward more due to friction. Sometimes if I know a certain string has a tendency to be pulled sharp while tuning other strings, I'll tune it slightly low so it will come up to pitch as the other strings are tuned.

This and humidity related expansion/contraction in the mandolin, and temperature related metal expansion/contraction in the strings and tailpiece, make mandolins very challenging to tune. When I am serious about tuning it almost always takes 2 passes of tuning every string, sometimes more.

Good luck with this!

Interesting! I hadn't thought of this. Sounds like it's time for a single subject repeated measures experiment with tuning order as an independent variable...

[sgosnell]

The old joke is that mandolin players spend half their time tuning, and the other half playing out of tune. It has also been used with other instruments, perhaps most notably harps, but there are more mandolin players.

[mandroid]

Humidity taken in, causes swelling of wood ... arch gets higher, distance further, so string tightened...

+ being such a short scale length, it's more noticeable.

carbon fiber does not do that...

[dhergert]

The old joke is that mandolin players spend half their time tuning, and the other half playing out of tune. It has also been used with other instruments, perhaps most notably harps, but there are more mandolin players.

Yup, of bluegrass instruments I've played banjo, mandolin, double bass, Dobro and a tiny bit of fiddle and of guitar. People often joke about banjos and tuning, and maybe they're just more obnoxious because when they are out of tune they are louder, but really the mandolin is the hardest instrument I've tried to tune.

12-string guitar might be tough too, but they're typically a flat-top instrument so it's not like trying to tune over a bubble.

When faced with tuning mandolins, I just reflect on how much worse it would be if I were tuning a hammered dulcimer.

[Mark Gunter]

All this has been covered already, but to underline what has been said: The nut slots (and saddle slots) must be a teeny bit wider than the string gauge; they should also be slanted downward a bit toward the the headstock at the nut & toward the tailpiece at the bride; they can also be lubricated with pencil lead or graphite. When tuning, you need to make several passes through the strings. Tuning a course of strings down a bit will lessen tension on the neck and the top plate, often enough to make the other strings a bit sharp on the mandolin (and vice versa). You’ll prove this to yourself over & over again. Make multiple passes with the tuner. Also, it is true that humidity as well as temperature will affect the tension on your strings, but unlike what I wrote above, this is down to Mother Nature, and the only resolution is to tune - as often as is necessary - and play.

[Leester]

We play mostly outdoor shows and this seems to challenge my mandolin to stay in tune. On the inevitable short pause in which I retune (while muted of course!) I offer the ancient observation that "mandolin is an Italian word that means out of tune" or "it was tuned when i bought it, I don't know what happened" On a serious note, pencil lead in the nut slots helps with the OP concern for me.

[sgosnell]

Another issue that causes tuning issues is that if the string is loosened slightly, the stiffness of the string causes it to be slightly loose on the capstan, but plucking it will over time cause it to tighten on the capstan and go flat. For this, I always tune up from below pitch, never down, and I give the strings a tug to tighten them on the capstans before I tune up to pitch.