Why does my guitar go sharp?

Talk about guitars, amplifiers, effects and other gear
User avatar
Golfxzq
Posts: 359
Joined: Sun Apr 04, 2010 3:13 am

Why does my guitar go sharp?

Post by Golfxzq »

I've noticed that whenever I leave my guitar overnight and check the tuning the next day all the strings are usually a little on the sharp side. Recently, due to a medical mishap with my wife, I have not had a chance to touch it for about a week. When I checked the tuning, sure enough, all the strings were sharp. It seems that the lower (ticker) strings tend to go more sharp that the higher (thinner) strings. To me it seems that since the strings have tension, as they sit they would naturally relax causing them to go flat.

Is there an explanation for this or is it caused by guitar goblins?

:guitarist:

Thanks
"Whether you think that you can, or that you can't, you are usually right."
- Henry Ford
User avatar
HalfBlindLefty
Admin
Posts: 2015
Joined: Fri Mar 26, 2010 1:23 pm

Re: Why does my guitar go sharp?

Post by HalfBlindLefty »

Please remind me so I don't have to search, what brand / type of guitar do you have ?
A long time ago, in the old forum : Registered: Mon, 27 Nov 2006. Wonder were the other old members all went....
CarolinaEd
Posts: 5
Joined: Sat Apr 17, 2010 12:29 pm

Re: Why does my guitar go sharp?

Post by CarolinaEd »

I notice this on my Epi Les Paul. I also notice that when it does go flat after sitting it will not hold a tune. Thus time to change the strings.
User avatar
BadBluesPlayer
Posts: 127
Joined: Tue Apr 06, 2010 6:31 pm

Re: Why does my guitar go sharp?

Post by BadBluesPlayer »

That happens to me if I play out in my workshop in the morning. If it's cooler out in my shop, I'll have to retune a little flatter. It could be a temperature thing.

:icon_whoknows:
User avatar
VikingBlues
Posts: 4466
Joined: Sat Apr 03, 2010 7:44 pm

Re: Why does my guitar go sharp?

Post by VikingBlues »

There is a theory that if the last time you played the guitar you retuned or tweaked the tuning during the session as the guitar and strings warmed up, then the guitar will have cooled down by the next time you use it, therefore the tuning will be sharp as the strings contracted with the cold. However if you only tuned at the beginning of the previous session and made no adjustments then this wouldn't be a factor.

I know with me, if I play early in the morning before I go to work (it puts my mind in a better state to cope with that ghastly idea :sad: :sad: :sad: :sad: :tears: ), I tune the guitar first and then spend the next 10 minutes tweaking the strings sharper as things warm up before they settle down and I get a settled quarter of an hour.

Also if you are picking up your guitar to play early the next day, when you'd played and tuned it the previous evening, the general room temperature might be lower.

Apparently you can also get this sort of tuning issue with guitars with trem arms.

Take all this with a pinch of salt, if not a mine full of the stuff. As I've shown in the past here, I'm no scientist, so I've not said any of the above from a position of knowledge. :alright:
An improv a day keeps the demons at bay!
cruisemates
Posts: 99
Joined: Fri Apr 09, 2010 6:31 pm

Re: Why does my guitar go sharp?

Post by cruisemates »

Cold temperatures will always makes things contract - like strings - so they would go sharp. As they warm up from playing they get looser and go hence longer, so they go flat. So you probably tune them up, then when you stop playing and the temperature drops overnight they go sharp again.
User avatar
Golfxzq
Posts: 359
Joined: Sun Apr 04, 2010 3:13 am

Re: Why does my guitar go sharp?

Post by Golfxzq »

HalfBlindLefty wrote:Please remind me so I don't have to search, what brand / type of guitar do you have ?
HBL... Co-Co is an Ibanez AF95 hollow body.

Cruisemates, VB, BBP... The temperature thing seemed the most logical to me too but, being an engineer, I did a little analysis. The strings and truss rod are steel and the neck and body are wood. There is a thing called coefficient of expansion which has been determined for various materials. It is a number which estimates the amount of expansion (or contraction) for each linear length of the material per degree of temperature change. Strangely enough, it doesn't matter how much mass of the material you have (for example a truss rod made of steel would have the same coefficient as a string made of steel) only the length of the material matters. SOOOO.... I measured my strings (30.5 inches) and multiplied that length times the coefficient of expansion for steel (0.00000645 in/in/F) and subtracted out that same length for wood (the guitar body and neck... after all, the wood would contract as well as the steel strings, just not as much). The coefficient of expansion for hard wood parallel to the grain is 0.0000027 in/in/F. Then I took this number and multiplied it times a temperature change to estimate how much my strings would contract for a particular temperature change.

Now I had to decide if that was significant. SOOO... I measured the diameter of my tuning pegs (0.02 inches), calculated how much the string would stretch with one revolution (0.628 inches). Then I hooked up my electronic tuner and sharpened my low E about the amount that it seems to be out after sitting a while. It was a very small amount of rotation of the peg, maybe one degree or even one-half degree (like one minute, or half-minute, on your watch... unless you are in the digital age, then go find someone old like me who has a traditional watch) One-half degree of peg-turn would be 0.628/120 = 0.005 inches.

To get 0.005 inches of string stretch, for my guitar, the temperature would have to go down 46 degrees F (7.8 deg C). Possible, I guess, but I don't believe that there is that much fluctuation in my home. Summer time is just beginning here in TN so the temperature is actually rising, not falling. I considered the air conditioner effect, but still... not 45 F.

OK... I guess this is pay-back for those extremely complex music theory posts that get me completely bum-fuzzled!!!
"Whether you think that you can, or that you can't, you are usually right."
- Henry Ford
User avatar
HalfBlindLefty
Admin
Posts: 2015
Joined: Fri Mar 26, 2010 1:23 pm

Re: Why does my guitar go sharp?

Post by HalfBlindLefty »

Ok,

Just a little test:
Tune the guitar while it is on it's stand. DON'T play it (sorry)
Next morning check if it's tuned little sharp.
If it's in tune, well......
A long time ago, in the old forum : Registered: Mon, 27 Nov 2006. Wonder were the other old members all went....
User avatar
VikingBlues
Posts: 4466
Joined: Sat Apr 03, 2010 7:44 pm

Re: Why does my guitar go sharp?

Post by VikingBlues »

Golfxzq wrote:Cruisemates, VB, BBP... The temperature thing seemed the most logical to me too but, being an engineer, I did a little analysis. The strings and truss rod are steel and the neck and body are wood. There is a thing called coefficient of expansion which has been determined for various materials. It is a number which estimates the amount of expansion (or contraction) for each linear length of the material per degree of temperature change. Strangely enough, it doesn't matter how much mass of the material you have (for example a truss rod made of steel would have the same coefficient as a string made of steel) only the length of the material matters. SOOOO.... I measured my strings (30.5 inches) and multiplied that length times the coefficient of expansion for steel (0.00000645 in/in/F) and subtracted out that same length for wood (the guitar body and neck... after all, the wood would contract as well as the steel strings, just not as much). The coefficient of expansion for hard wood parallel to the grain is 0.0000027 in/in/F. Then I took this number and multiplied it times a temperature change to estimate how much my strings would contract for a particular temperature change.

Now I had to decide if that was significant. SOOO... I measured the diameter of my tuning pegs (0.02 inches), calculated how much the string would stretch with one revolution (0.628 inches). Then I hooked up my electronic tuner and sharpened my low E about the amount that it seems to be out after sitting a while. It was a very small amount of rotation of the peg, maybe one degree or even one-half degree (like one minute, or half-minute, on your watch... unless you are in the digital age, then go find someone old like me who has a traditional watch) One-half degree of peg-turn would be 0.628/120 = 0.005 inches.

To get 0.005 inches of string stretch, for my guitar, the temperature would have to go down 46 degrees F (7.8 deg C). Possible, I guess, but I don't believe that there is that much fluctuation in my home. Summer time is just beginning here in TN so the temperature is actually rising, not falling. I considered the air conditioner effect, but still... not 45 F.

OK... I guess this is pay-back for those extremely complex music theory posts that get me completely bum-fuzzled!!!
Wow :yikes: - I'm glad I put in my disclaimer about having no knowledge!! :big_smile:

When I sit back and think where I've accumulated my "knowledge" of guitar related issues from and how unreliable many of those sources are I realise so much of it could be pure "horse-hockey" (if that's the expression I'm after). There's a lot of real knowledge given out on this site - not just rehashed hearsay. I'm glad to have read your post, and I'm glad someone else has a traditional watch too. :thumbsup:

If it's any help Golfxzq "those extremely complex music theory posts" have my brain shutting down faster than the banks in a recession. I've seen theory behind how to play pieces I've done and it means zilch to me. Oh well - I'll just stick with using my ears 'cos my brain just won't play ball.

Mind, I think it is the case that the better you get as a guitarist the more you notice when the guitars not in tune. :sad:

Nice guitar you have btw - am I right in thinking it is a fully hollow one without the central block? :icon_whoknows:
An improv a day keeps the demons at bay!
User avatar
MojoJim
Posts: 222
Joined: Mon Mar 29, 2010 6:38 pm

Re: Why does my guitar go sharp?

Post by MojoJim »

Golfxzq,
Love the analysis - just love it! (Engineers - and geezers - rule!) :clap: :thumbsup:

It clearly proves that the cause is indisputably, irrefutably, scientlifcally proven and without doubt - guitar gremlins! I wouldn't worry about the guitar. I would be setting live traps for the gremlins. Catch and Release is the only humane way to deal with them. :wink: :whistle: :lol:
User avatar
Golfxzq
Posts: 359
Joined: Sun Apr 04, 2010 3:13 am

Re: Why does my guitar go sharp?

Post by Golfxzq »

JimRR wrote:I would be setting live traps for the gremlins. Catch and Release is the only humane way to deal with them. :wink: :whistle: :lol:
That's the only reasonable explanation.... all else has been scientifically proven to be of no consequence!
VikingBlues wrote:Mind, I think it is the case that the better you get as a guitarist the more you notice when the guitars not in tune. :sad:

Nice guitar you have btw - am I right in thinking it is a fully hollow one without the central block? :icon_whoknows:
I'll be glad when I get to the point where I can tell she is not in tune without relying on my electronic tuner.

Yep... That's Co-Co, I plan to introduce her to ya'll (southern expression) soon. I want to get a good portrait made first. Yes, she is a full hollow body, no block. I fell in love the minute I saw her hanging way, way up on the shop wall in the corner completely ignored. It was love at first sight.
HalfBlindLefty wrote:Just a little test:
Tune the guitar while it is on it's stand. DON'T play it (sorry)
Next morning check if it's tuned little sharp.
If it's in tune, well......
Good suggestion... I'll try that tonight. Usually I practice in the evenings. I tune her up first and then play. Occasionally I'll re-tune in the midst of practice if something sounds a little strange but mostly not. I do not normally tune at the end of my practice session so tonight I'll be sure to tune her up good and then check it first thing tomorrow morning and again tomorrow evening before practice. That will allow about 24 hours for the gremlins to do their thing.

I have notice before that every time I check her tuning it seems to be sharp, not flat, but not much. This week has been a little unusual in that I have not had a chance to practice for about a week and all the strings were noticeably sharp. I just could not figure out why sharp and not flat? Maybe she is just going sharp due to the playing. We'll see what your test shows. Thanks for the suggestion.
"Whether you think that you can, or that you can't, you are usually right."
- Henry Ford
User avatar
nxsneil
Posts: 43
Joined: Tue Apr 06, 2010 6:53 am

Re: Why does my guitar go sharp?

Post by nxsneil »

This also happens with my '72 Gibson SG, in perfect tune when I stop playing, pick it up the next day and is slightly sharp altho mine is mainly on the thicker strings :icon_whoknows: I'll go with temperature/gremlins :beer:
-----------------------------------------------------------------------
Someday I aint gonna worry my life anymore....
User avatar
HalfBlindLefty
Admin
Posts: 2015
Joined: Fri Mar 26, 2010 1:23 pm

Re: Why does my guitar go sharp?

Post by HalfBlindLefty »

Golfxzq wrote:
HalfBlindLefty wrote:Just a little test:
Tune the guitar while it is on it's stand. DON'T play it (sorry)
Next morning check if it's tuned little sharp.
If it's in tune, well......
Good suggestion... I'll try that tonight. Usually I practice in the evenings. I tune her up first and then play. Occasionally I'll re-tune in the midst of practice if something sounds a little strange but mostly not. I do not normally tune at the end of my practice session so tonight I'll be sure to tune her up good and then check it first thing tomorrow morning and again tomorrow evening before practice. That will allow about 24 hours for the gremlins to do their thing.

I have notice before that every time I check her tuning it seems to be sharp, not flat, but not much. This week has been a little unusual in that I have not had a chance to practice for about a week and all the strings were noticeably sharp. I just could not figure out why sharp and not flat? Maybe she is just going sharp due to the playing. We'll see what your test shows. Thanks for the suggestion.
That procedure will tell only half of what I want to know, sorry.
If you are going to practice anyway, let her on the stand, untouched for a hour or 2. Then check the tuning and retune ! ( I hope 2 hours will be enough to get her in a ~stable state).
Then check again next day.
It could be a good idea to check (and take a note) of her tuning after playing. At least for me the following is true.
When I start playing, I do a chord check or 2 to hear the tuning between the strings. If that is ok I don't bother tuning at all. (most of the time). If needed I will tune her.
During playing, especially when I don't use backingtracks or other songs to play to, I won't notice when a string goes out of tune just slightly. I don't play chords to often, so..
If after a while I fire up a bt or a song and play along, sometimes I have to tune ! That may be my hearing, but also maight as well be due to the fact that I need a reference note to tell if a string is out of tune.
What I'm saying is : Most people won't notice -by ear- that a string is ever so slightly out of tune (without a reference) One practices and puts the slightly ot of tune guitar aside... next day, before starting, the tuner will tell the tale :)
The other thing is I notice guitars -can- act different (tuning state) to a wall hanger, a stand or a corner (stand), or even to just being played (ever so slight detunings)

Mhh, I'd better re-read this post in a hour or two, I'm just awake and not so sure I put down correctly and ce\lear what I wanted to tell..... :wall:
A long time ago, in the old forum : Registered: Mon, 27 Nov 2006. Wonder were the other old members all went....
User avatar
Golfxzq
Posts: 359
Joined: Sun Apr 04, 2010 3:13 am

Re: Why does my guitar go sharp?

Post by Golfxzq »

HalfBlindLefty wrote:That procedure will tell only half of what I want to know, sorry.
If you are going to practice anyway, let her on the stand, untouched for a hour or 2. Then check the tuning and retune ! ( I hope 2 hours will be enough to get her in a ~stable state).
Then check again next day.
Good point HBL... I read your post this morning so here is what I did:

4-17-10 8:00 pm - Tuned her up as closely as possible.
Practiced.
9:30 pm - Checked tune: Low E and D were slightly sharp. All other strings were right on.
Re-tuned E and D as close as possible and set here aside for the night.

4-18-10 10:00 am - Checked tune: A and Low E were slightly flat (go figure?? Gremlins are fickled !) All other strings were dead on.
Re-tuned the A and E as close as possible and set her aside for the rest of the day.

8:00 pm - Checked tune: Low E was very, very, slightly flat. Not really enough to worry about, but definitely flat, not sharp! All other strings were still right on.

Co-Co sits comfortably on a stand, she is never hung by the neck.

Does anyone draw any conclusions from this test? I am a little surprised that after sitting overnight to "stabilize" and then tweaking the tuning she pretty much stayed in tune for the rest of the day. Maybe I'm making too much of this but it just seemed to me that most of the time she would end up sharp before each practice session and after sitting idle for a week she was noticeably sharp, just the opposite of what I would expect.

Guitar Gremlins... :angry:

p.s. Thanks for all the well-wishes for my wife's health. She is steadily improving each day. Walking with a walker, should be back as wonderful as ever in about eight weeks.
"Whether you think that you can, or that you can't, you are usually right."
- Henry Ford
User avatar
12bar
Site Admin
Posts: 3273
Joined: Thu Mar 25, 2010 12:05 pm

Re: Why does my guitar go sharp?

Post by 12bar »

I just saw the other post - congrats to your beautiful guitar! :thumbsup:

My thoughts (chemical engineer... :yikes: ):

I think the temperature expansion effect on the strings is not the only cause. Your guitar is made of wood, and wood is not as "reproducible" as steel, it "lives" as the joiners say. The temperature effect on real wood is not linear, humidity also has a great effect on it. If you get a relatively new guitar the wood will dry and tighten, this may change the "bow" of the neck. Changing humidity has a much bigger effect on the wood than changing temperature alone, and the air temperature also effects directly the humidity... :think:

If you have a guitar case, you should try it. To get more data for troubleshooting. :big_smile:
User avatar
weelie
Posts: 228
Joined: Wed Apr 07, 2010 10:23 am

Re: Why does my guitar go sharp?

Post by weelie »

Guitar might go out of tune if the top (if it's a hollow body guitar) or neck reacts to humidity/temp changed , or if the nut is not cut right (or there's friction elsewhere, like at the bridge... or floating bridge).
User avatar
Blindboy
Posts: 1787
Joined: Sun Apr 04, 2010 3:34 pm

Re: Why does my guitar go sharp?

Post by Blindboy »

12bar and weelie are right; the wood in the neck and the top will be affected by temp and humidity far more than the strings themselves. Being a new guitar, she may settle down a bit as time goes by, too. When I take mine to town to play, there is a 3000 foot elevation difference. When I first got the guitar (Ibanez Artcore) it would be noticably sharp. Last night, (after owning it for 5 or 6 years) it was almost spot on, even with a rainstorm creating a large humidity change as well as the elevation change.
"Throw yo' big leg over me Mama, I might not feel this good again!"
User avatar
Golfxzq
Posts: 359
Joined: Sun Apr 04, 2010 3:13 am

Re: Why does my guitar go sharp?

Post by Golfxzq »

12Bar wrote:Changing humidity has a much bigger effect on the wood than changing temperature alone, and the air temperature also effects directly the humidity... :think:
BlindBoy wrote:2bar and weelie are right; the wood in the neck and the top will be affected by temp and humidity far more than the strings themselves. Being a new guitar, she may settle down a bit as time goes by, too.
weelie wrote:Guitar might go out of tune if the top (if it's a hollow body guitar) or neck reacts to humidity/temp changed , or if the nut is not cut right (or there's friction elsewhere, like at the bridge... or floating bridge).
I think this is spot on... I am sort of a Mechanical (actually an Aerospace), not a Chemical, so I didn't really think much of the humidity effects or the "time factor" (5 or 6 YEARS?? Wow). From all of this... I take that it is a combination of temperature, humidity, time, and maybe even barometric pressure (elevation change per BlindBoy). Anyway, after the test suggested by HBL it seems to stay pretty stable overnight if I tune it up, let it set for a while and tune it again.

This really has noting to do with actually PLAYING :music2: Blues but it has stimulated my mind just the same. Thanks for all the helpful info. Now... back to the scales, chords, theory, blue notes, 7th chords, etc., etc., etc. :think:
"Whether you think that you can, or that you can't, you are usually right."
- Henry Ford
User avatar
HalfBlindLefty
Admin
Posts: 2015
Joined: Fri Mar 26, 2010 1:23 pm

Re: Why does my guitar go sharp?

Post by HalfBlindLefty »

Try a 7 or a 9 chord with some strings out off tune :) ....yuk

Mhh, I was still trying to rule out some things, but it would have taken me a while to get to the humidity thing. I was still thinking nut slots... :D
A long time ago, in the old forum : Registered: Mon, 27 Nov 2006. Wonder were the other old members all went....
User avatar
12bar
Site Admin
Posts: 3273
Joined: Thu Mar 25, 2010 12:05 pm

Re: Why does my guitar go sharp?

Post by 12bar »

Golfxzq wrote:I take that it is a combination of temperature, humidity, time, and maybe even barometric pressure
+ the guitar Gremlins... :big_smile:
Post Reply