While using an electronic tuner the other day I inadvertently came across something I find odd. I tuned my guitar and all the open strings registered on the tuner as being in tune, however, when I began to fret some notes they all showed up as being sharp. Does anyone have any idea why this might be? Is it more likely me or the fact that I am using a cheap guitar? And if it is the guitar is there anything I can do about this? (other than buying a better guitar)
A couple of easy answers...you might be pushing down too hard on the string you're fretting. It only needs to touch the fret you want, it doesn't have to touch the neck between the frets as well. Pressing too hard will make it sharp. Also, if your action is too high, each note played that is not open, will be sharp as well. I have many cheap guitars (too many my wife says!!!) and I can usually keep them in tune. If you're uncomfortable adjusting the action yourself, you should be able to find a guitar shop locally that can do it for cheap. Finally, if it's never been properly "set-up", you may need the intonation checked (the variation of the open string to the 12th fret). The guitar shop should be able to handle that as well. My $.02:)
Michael is right about the string not having to touch the neck. In fact the closer you place your finger to the metal fret itself, the better -- purer tone and no buzz.
I also agree with the intonation side of it. If your in tune when open, and not when you fret the 12th fret then the intonation is off. If your in tune when open and in tune on the 12 fret, then it is an issue of pressing to hard.
If the intonation is off, there isn't much you can do about it on an acoustic (Electric is a different subject and easier to fix). You may be able to offset it by adjusting the neck or shimming or sanding the saddle. But you may run into string height issues by sanding just portions to adjust the intonation.
First, you haven't mentioned the brand or model guitar you are speaking of. What is the guitar?
Next, like everyone else is saying, the intonation is likely the issue. While you can do some basic stuff, you are going to be limited in doing a proper setup on an acoustic. It would be well worth it to take the guitar to a luthier and have them go over the guitar completely and do all the necessary setup to get the intonation and other playing aspects of the instrument in proper order.
Unlike electric guitars, simply turning a couple screws at the bridge to adjust the string length and height is not possible. It's always best to have a guitar, especially a newer one (even a cheap one) setup by someone who knows what they are doing. There is a lot more involved than you think that can affect the intonation - right down to the gauge of the strings.
Thank you all for the replys. This has been very informative. I never even knew you could fret a note without actually touching the fretboard. I checked intonation again with a lighter touch and also at the 12th fret. The intonation is 'less' sharp with a lighter fretting as well as being sharp mostly on the heavier strings rather than all 6 so it seems it IS mostly an intonation problem. As for my guitar, it is a Mitchell MD-100S. I got it new at Guitar Center on sale for $99. I chose this guitar because it was the cheapest I could get with a solid spruce top. I am using D'addario phosphor bronze custom light strings. I believe I will go back to Guitar Center for a set-up. I never had it done because I didn't think it would make much difference on such an inexpensive guitar. Do you think it would help any if I changed out the nut and bridge to bone or Tusq? Once again thanks for the help. I am teaching myself with the help of some of the free online lessons I can find and this forum has been invaluable to me
I'll just throw this in as an FYI. I just had work done on my acoustic by a pro. He recommended redoing the saddle to address some intonation correction. He removed the old 1 piece straight-line saddle, milled the bridge down and installed an articulated saddle (= two pieces, 1 for bass, 1 for trebble, each on an slight angle from the edge of the bridge). I can't believe what a difference this has made. Sounds amazing! Who knew?