Why Does My Guitar Go Sharp?

Tmcqtele65

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I'm finding that my guitars are commonly a tiny bit sharp when I start. The "sharpness" is usually fairly consistent - as in, it is reasonably in tune with itself, just sharp. Every once in a while, but far less commonly, a guitar will be a bit flat. My house is pretty well climate controlled - consistent temperature between 70 and 75, and I keep a humidity meter in the room (always between about 42 and 65%). I keep all my guitars on a typical guitar stand. Just curious what makes a guitar go sharp...flat, I understand.
 

MickM

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Mine too. Barely sharp, in tune with itself but all strings a tiny bit sharp.
It seems to be mostly this time of the year with the a/c running same temp as yours.
 

BFcaster

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I notice a slightly high string height results in a slightly sharp note. If all your guitars do this, maybe lower one guitar's strings to test this. Action, neck relief and height of frets can play a role too.

Just my own observation, so take it with that in mind.
 

Peegoo

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It's temperature-induced.

When you play, your fingers on the strings warm them up a few degrees; that causes expansion of the metal. You tune the guitar and all is good. When the guitar is hung up or put away in the case, the strings cool off and contract a little bit, making them go sharp. It takes just a few degrees of temperature differential for this to occur.

Next time you pick up your guitar, run the palm of your hand up and down the strings about 10 times to create a little friction and warm the strings, and report back.
 

NoTeleBob

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Could be strings warming... or the neck moving. If it's consistent across the strings, I'd lean towards the neck moving. I'm in the habit of holding the low-E at the 1st and 17th every time I pick up a guitar to play so I can check relief at the 8th. You'd be surprised how often I can see it's moved. Not a lot, but enough to matter.
 

Peegoo

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If you've ever played outside and the sun is shining on you and your guitar:

Devil-Guitar.jpg
 

Jason McG

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it's humidity; wood shrinking or swelling, depending on whether its taking on moisture or losing it, to try to reach equilibrium with the relative humidity at the time. The sharpness, when humid, is the fingerboard swelling, lengthening slightly, and introducing a touch of back bow.
 

AAT65

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If you've ever played outside and the sun is shining on you and your guitar:

Devil-Guitar.jpg
I've had the opposite problem -- gigs so cold your fingers can barely work the tuners let alone fret the notes... one gig there was a space heater in back so we could try to warm ourselves before we went on, that did not help the tuning when we went out on stage...
 

kuch

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A couple of you guys got it right. heat, humidity, air pressure.....
my guitars do it too

I've always believed that all guitars, even electrics need about 10-15 minutes of playing to "warm up"
 

oldunc

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Very common with guitars- sometimes it's obviously influenced by temperature change, but sometimes they just do it. Nylon strings are worse that way.
 

Si G X

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I don't know for sure (and maybe it's several things) but I usually experience this at band practice in winter. I've always presumed the cold temps make the metal in the strings contract.
 

Marc Morfei

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I also suspect humidity. The wood swells a bit with more humidity, enough to make it a tiny bit sharp. If the issue is common to all the strings at once, then it's nothing to do with intonation or the nut.
 




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