What makes strings go sharp?

[Wade Hampton]

Today I grabbed a mandolin on the way out the door to play music. I hadn’t played this particular instrument in a few months, and when I got it out of the case at my friend’s house I discovered that the strings were sharp, some of them by quite a bit.

What makes strings do that? You’d think being left unattended would cause them to go flat, not sharp.

Just curious…


Wade Hampton Miller

[cheer tunes]

For me strings go sharp when the humidity shifts lower. Was in the mountains this weekend and it rained a lot. When i returned home last night and put the guitar in my room (dialed in at 50%) every string was sharp (still in tune relatively) this morning.

That's my story and I'm sticking to it

[rick-slo]

Temperature and humidity variations (mainly humidity which when goes higher over a period of time causes strings to go sharp).

[Rudy4]

Originally Posted by Wade Hampton

Today I grabbed a mandolin on the way out the door to play music. I hadn’t played this particular instrument in a few months, and when I got it out of the case at my friend’s house I discovered that the strings were sharp, some of them by quite a bit.

What makes strings do that? You’d think being left unattended would cause them to go flat, not sharp.

Just curious…


Wade Hampton Miller

I have a pretty nice carved top F hole mandolin, spruce top and figured maple back / sides that I made and have been playing for something like 20 years.

It's the only instrument that I have that reliably shifts pitch upward when it is set aside in its bag for a month or two.

I attribute it to the carved solid spruce top. It seems like if I gig with it then it is stable after tuning it and it always does the upward shift thing after putting it away for a while. It seems to also be humidity related, and the pitch shift can be as much as a half step.

Other than the carved spruce top it isn't really any different then other instruments I own.

I'll be interested to see if anyone has a more specific reason for this "odd" quirk with our mandolins.

[MJScott]

I have always found that mandolins are more sensitive to humidity than guitars. If left in a case for a while without playing they always are out of tune and frequently need new strings. Picky little instruments.

[poopsidoo]

Originally Posted by Wade Hampton

Today I grabbed a mandolin on the way out the door to play music. I hadn’t played this particular instrument in a few months, and when I got it out of the case at my friend’s house I discovered that the strings were sharp, some of them by quite a bit.



What makes strings do that? You’d think being left unattended would cause them to go flat, not sharp.



Just curious…





Wade Hampton Miller

I’ve noticed that a lot. Has to be the neck pulling back

[merlin666]

Happens every spring to me when humidity goes up and instrument bodies expand and stretch strings

[B. Adams]

As noted, changes in temperature and humidity are the biggest culprits.

Also, this is just my opinion, but I think strings stretch the slightest amount due to the act of playing, and when you let it sit for a while they compress just a tiny bit going slightly sharp. So I'd say if you haven't played it for a while, play it for a bit, even just muted strums, to stretch the strings back out before you tune it the first time. If you do that you might not have to retune quite as quickly.

That's based on the fact that my carbon fiber instruments do this too if they sit for a while, and they're incredible stable. They settle in after a bit of playing though, as do my wooden guitars.

[zmf]

For me, living above 7000 ft in the dry Rockies, strings go sharp on my most lightly built guitar when I'm away for 5-7 days. My working hypothesis is that the guitar doesn't come out of its case, and humidification in the case is higher than ambient humidify it experiences when it regularly comes out of the case.

The guitar absorbs water, swells, scale length effectively increases, and it tunes sharp.

Please critique this hypothesis.

[Wade Hampton]

Originally Posted by Rudy4

I have a pretty nice carved top F hole mandolin, spruce top and figured maple back / sides that I made and have been playing for something like 20 years.

It's the only instrument that I have that reliably shifts pitch upward when it is set aside in its bag for a month or two.

I attribute it to the carved solid spruce top. ….

For what it’s worth, the mandolin I experienced this with today is a National resonator mandolin, so it doesn’t have a spruce top, carved or otherwise.


whm

[KevinH]

Originally Posted by B. Adams

As noted, changes in temperature and humidity are the biggest culprits...

I don't think temperature has much to do with it. Metal expands/contracts more than wood (at least along the grain direction as in a guitar neck), by about a factor of 10. Suppose the temperature drops by 5C (9F) as an example. The steel strings will want to contract, raising the pitch and making them sharp. But, using the coefficient of thermal expansion and the modulus of steel, it turns out the pitch of a B string will only go up about 1 cent - hardly noticeable (assuming I did the math right). And it will probably be even less than that because, the neck will contract as well, though much less than the string, which would alleviate part of the increase in tension and frequency.

So, probably something other than temperature.

[OKCtodd71]

The most stable tuning environment I've ever experienced was when I lived in Florida; with the central AC running at least 10 months out of the year you get a pretty steady temp and humidity level.

[N4640W]

Ahhhh, South Flatistan with its notorious humidity……overcome by a/c 24-7. The age of miracles. Nothing better for wooden instruments and human skin. If the a/c fails, (as in hurricanes, thermonuclear pulse weapons or power grid failures), the neg effect on the wooden instruments will be much more tolerable than in, say AZ, CO, Green Bay WI or Siberia. And no state income tax!

[donlyn]

What makes strings go sharp?

Fretting them, among other things.

Mostly I blame changing atmospheric conditions, combined with the material and build of an individual guitar. Small body and laminate guitars seem less affected overall. Also heavily built guitars, like say a J-200, adapt less radically to changes than lightly built large guitars. And if they are all sharp or flat to the same small degree, it won't sound so bad anyway. Yeah I know that is heresy, but for a quick practice it shouldn't matter. And if it's that noticeable, then it's time for a tuning anyway.

Don
.

[FLRon]

I have wondered about this for many years. My Larrivee C-10 will pull sharp every time (usually once a week) I take it out of the case. It did it in Ohio and it does it in SW Florida.