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“I’ve noticed that playing an open A chord on some guitars sounds right, while on others it sounds slightly out of tune. I have a lot of guitars and actually play them all, and use a Peterson HD strobe tuner for tuning and setting intonation. Also, it’s not as I would expect: the more expensive ones sounding great and the cheaper ones with poor sounding A chord. I do keep the action low and strings fairly new.”
Whenever you’ve got intonation set properly but one or two lower-position guitar chords sound out-of-tune, it’s almost always a nut issue:
- The nut may be too high, which makes the action higher than it should be at the nut. So, when you press the strings down the notes are literally pulled sharp due to the extra distance the string has to stretch (much like bending a note)
- The overall nut height is fine, but the string slots themselves aren’t deep enough, which can cause the same effect as #1
- The string slots are shaped improperly–where the breakpoint of the string over the nut is too far forward or backward. This creates a problem similar to when your bridge saddles are too far forward or backward.
Sometimes, it’s a combination of those factors. Sometimes, there’s absolutely nothing wrong with your guitar, but I’ll talk more about that at the end of this article.
Usually, this is more noticeable with certain chords. Open D and A chords are the usual suspects, but other chords can stick out as well, depending on the guitar and how bad the nut is.
These issues can be fixed by deepening and/or reshaping the individual string slots a bit. However, simply filing them deeper isn’t enough–there’s some skill involved in doing it right so that strings don’t buzz or bind in the slots. So, it’s best left to a pro unless you’re willing to learn the technique so you can (properly) do it yourself. It IS a necessary skill if you want to do your own guitar setups. However, don’t do your very first nut job on an expensive guitar. Always practice on a cheap guitar or junk neck (which you can find all over ebay) first.
Nut-height is almost always a problem with cheap guitars. The nut is the #1 thing that gets glossed over or rushed during final QA at the factory because it requires a bit of time and finesse to get just right. So, factories usually err on the side of leaving the nut too high, which avoids fret buzz but can cause high action and poor intonation (though not always). They assume the future owner will have the guitar set up, and lower the nut action to their liking. A high nut leaves the future owner plenty of “meat” to remove, as necessary.
On the other hand, the nuts on very expensive and high-end guitars usually get a lot more attention before they leave the factory. That’s why nut issues tend to be rarer on high-end guitars.
However, even after you’ve got the action at the nut properly dialed-in, the fact is that guitars are imperfect instruments due to their fixed frets. You’ll never have perfect intonation over the entire fretboard. Compensated nuts can help, but the only way to get nearly perfect intonation everywhere is with something like the psychedelic looking (and pricey) True Temperament fretting system.
Or, It Might Just be Your Ears
Even after you’ve got the action at the nut properly dialed-in, the fact is that guitars are imperfect instruments due to their fixed frets. You’ll never have perfect intonation over the entire fretboard. Compensated nuts can help, but the only way to get nearly perfect intonation everywhere is with something like the psychedelic looking (and pricey) True Temperament fretting system.
Don’t Believe Me? Watch This Video
So, I’m actually incapable of explaining… scientifically… what’s going on when your in-tune guitar sounds out-of-tune while you’re playing. However, I happened across a video that does explain things. Warning: it’s a tad difficult to watch, but if you’re patient, it’ll help set your mind at ease and perhaps help you accept that there may not actually be anything wrong with your guitar, nor you, for that matter:
Lastly Dan, kudos for using the Peterson HD Strobe Tuner. For the money, it’s an amazing little strobe tuner–the same one I use. Have you experimented with their sweetened tunings at all? They’re supposed to help remedy these types of intonation issues (assuming action is set properly at the nut and bridge). Don’t set your intonation while in a sweetened tuning mode though. Dial-in your intonation in normal mode first, then use a sweetener for normal tuning after that.
Hope that helps!