Strings getting flat at higher frets?

Hey everyone

As I get higher up the neck (12th fret and up is when it starts getting noticable), the strings start getting flat...in other words, an open E is in tune, but at the octave it is a little flat. I had the intonation and truss rod and everything set properly a few months ago when I put on heavier strings.
What is causing this and how can I fix it. (I was thinking that it's just a matter of the strings being worn out but I'm not sure).

Thanks

Believe it or not, this is quite common and from what I understand realitively normal for a guitar to "flatten" as you move up the frets. I have a Godin electric I have had setup 3 times and had 2 new nuts made for it for this same problem and at the same time, my g string seems sharp after the 3rd fret. The guitar techs who did the work told me of an old saying, "guitar players spend half their time tuning their guitars and the other half playing out of tune."

Sounds to me like the intonation wasn't actually done properly, if it was done at all. Intonation is set by making the open string the same as the 12th fret note (more or less). So if that's out then it means your intonation is out altogether.

If you have an accurate tuner it's not difficult to do it yourself, by the way. What kind of guitar do you have?

What about an acoustic guitar that goes out the closer i get to the 12th fret.As best i can tell it has a fixed bridge and saddle. By the way i didn't change the strings recently. I just noticed it recently. Its an Ibanez guitar.

Originally Posted by: Mark PavSounds to me like the intonation wasn't actually done properly, if it was done at all. Intonation is set by making the open string the same as the 12th fret note (more or less). So if that's out then it means your intonation is out altogether.

If you have an accurate tuner it's not difficult to do it yourself, by the way. What kind of guitar do you have?

That's a good [u]start[/u].

Then compare the [u]fretted[/u] notes at the 3rd & 15th, 5th & 17th, 7th & 19th.

Right well the thing is, I wasn't having this problem right after I got it back...only seems to have cropped up recently. Could this be from worn out strings?

Oh and I have a Godin exit 22.

Originally Posted by: ike030585Could this be from worn out strings?

Yep. That's a definite possibility.

Originally Posted by: ike030585... Could this be from worn out strings? ...

Oh, yes. Its sometimes helpful to remember that the 'classic' Tele's that so many players love, were built with three bridge saddles that each support two strings. This configuration is unavoidably impossible to accurately intonate. And yet arriving at the personally-selected combination of compromises that this impossible situation imposes on a player often results in seriously toneful music.

So try a new set of strings and a 'fresh' listen to your guitar. If it still doesn't sound right, you should at least have some insight into the changes you want a setup to achieve. And that gives you a set of goals for your tech to aim for.

intonation will depend on how hard you press on the strings. you can set intonation to play single notes, but when you play chords, your guitar will be somewhat out of tune, especially if you have jumbo frets.

Buzz Feiten system is another way to handle this.