Ask the Expert – why won’t my guitar stay in tune?

Tuning a guitar

Andy Shaw, a worship leader from New Malden in the UK emailed saying:

“Can I ask a question about keeping your guitar in tune when playing live. I play electro-acoustic, normally a jumbo Tanglewood. Often, I tune up the guitar for rehearsal but once I have been playing for a while, the strings have gone out of tune, normally sharp. When I put the guitar back down, the strings settle back down but then seem flat! Then I don’t know whether to re-tune for the live situation. I have put it down to atmospheric conditions since it seems worse in the extreme months (high summer or deep winter). The B string seems particularly prone to going in and out of tune.

Kind of in a quandary to know whether to (i) tune up after we have warmed up for a while or (ii) leave the strings alone even if slightly flat, knowing that once we have started again, they will fall back into the right tuning. Does that make sense?? Is it my strings (I use D’Addario EJ16s) or tuning heads (this Tanglewood has Grover heads) instead? Any advice you can offer much appreciated!

Finally, thanks for all the great work and fab resources – I use many of them.”

Andy (Chamberlain) replies:
To be honest, you and your congregation both deserve an instrument that stays properly in tune without compromises. Your guitar going out of tune could be down to a variety of reasons, they should all be fixable, but it’s hard to pinpoint without seeing it so here are some things you could check.

Firstly, make sure the strings have been changed recently and are fresh. Secondly make sure they are properly stretched in. You can do this by tuning to pitch and then tugging firmly on the string a few times whilst keeping it anchored against the fret board with your left hand at various frets. The string will go flat as it stretches so repeat the process two or three times and your string should now stay at pitch. I wouldn’t ever recommend tuning sharp in the hope that the string will eventually de tune to pitch.

If your strings are pulling sharp the source of your problem could well be the nut. The nut is the plastic part at the headstock end of the guitar that the strings pass over before they attach to the tuning pegs. Each groove that the string sits in needs to be cut uniformly so it doesn’t pinch the string, causing friction and perhaps not letting it return to pitch after the string his been hit, thus keeping it pulled sharp. The nut also needs to be cut flat so that the string doesn’t run over a sharp fulcrum and cause tuning instability or even string breakage. If you know what you are doing you can address this with a file, but any mistakes are irreversible so if in doubt, employ a proper guitar repairer or luthier to sort it out. Secondly, the nut needs to be lubricated. This is easy to sort by shaving some graphite from a pencil into each slot so give it a try first and see if it helps.

Another possibility is that your capo (if you use one) is pulling the strings sharp. This is particularly noticeable if the guitar has large frets. Try either buying a capo with less tension in the spring (the G7th Nashville is good in this respect) or a ‘shubb’ type that you manually screw into place. Another trick is to place the capo directly on top of the fret rather than just behind it.

Every guitar needs setting up from time to time, just like a car would need a service, and if done properly issues like this tend to disappear, plus it could vastly improve the feel and playability of your guitar. There are plenty of resources on the web to help you do this but if in doubt take your guitar to a decent instrument tech or repairer who should be able to pinpoint the problem with ease.