I have an acoustic. I can get all the strings perfectly in tune, and they hold tuning, so the guitar can't be too awful. But on certain strings (the B and the D), as I go up the neck, each note past the first fret or so is about 20 cents sharp. 20 cents sharp is unacceptable for my ears. I don't know why it does this. I can handle five or ten cents, but 20 is painful.
Any ideas?
that is an intonation problem. odd that it occurs on those two strings. the bridge is set too far back; thus sharp.
or , is it too close and sharp? dislexic moment here.
does the bridge saddle look worn? does it look original?
my stab.
Do the B and G strings appear to be "standing up" higher than the other strings? If the other strings hold their tune, I would GENTLY sand some of the TOP of the saddle under the B and G strings. It sounds like it's a replacement saddle. I've made bone saddles for all my acoustics and they sometimes need fine tuning to get them right. Just be careful to keep the angle of the top correct. Too sharp an angle can cause the string to break.
Take a look at the nut. A lot of intonation problems stem from the nut being too high, or a slot or slots in the nut not being cut deep enough so that some strings are too high at the nut.
"A cheerful heart is good medicine."
Hmm... sounds like the sort of thing I don't mess with much. The saddle looks like it's original, although at the high E end, it's very low, almost flush with the bridge, then it gets higher, and then a little lower again for the low E.
