Changing tunings safely

What changes when you retune

A string’s tension rises with the square of its frequency. Each semitone multiplies the frequency by the twelfth root of 2, so each semitone changes the tension by that ratio twice over. For a string kept the same:

• Up 1 semitone: about 12% more tension.
• Up 2 semitones: about 26% more.
• Down 1 semitone: about 11% less.
• Down 2 semitones, as for string 6 in drop D: about 21% less.
• Down 5 semitones, as for string 6 in drop B: about 44% less.

The tuning changer works this out string by string for any two tunings, including which way each string has to go.

Those numbers explain the basic rule. Lowering is gentle. The worst outcome is slack, buzzing strings. Raising is where damage happens. Extra tension can snap a string, pull the neck into more bow, and on an acoustic, add strain to a bridge that is held on only by glue.

Raise strings with care. A semitone above where a set is designed to sit is usually fine. Two or more is asking for trouble with normal gauges. When a song calls for a higher pitch, use a capo instead. When you choose between tunings that use the same shapes, pick the lower one: open D uses the same shapes as open E a whole step lower, and open G does the same for open A, so neither needs extra tension.

Tune down, then up to the note

The rule from everyday tuning matters even more during a tuning change. For a string that has to go up, tighten it to the note as usual. For a string that has to go down, loosen it past the target until the tuner reads clearly flat, then tighten slowly up to the note. Coming down onto a note leaves slack in the gear and friction at the nut, and that slack lets the string slip flat a few minutes later.

For large changes, spread the work across the guitar. Bring every string roughly to its new pitch first, then fine-tune. The neck and bridge move as the total tension changes, so perfecting one string while the others are far away is wasted effort.

Changing tunings with HeyTuner

1. Choose the new tuning in the tuner’s menu, or open its page, such as drop D or DADGAD. The drop tunings and open tunings hubs list them all.
2. For changes of more than a semitone, turn Detect String off and tap the peg you are tuning. The reading stays locked to that string and tells you how many semitones to go, so a string far from its target is never mistaken for its neighbor.
3. The tuning transition helper shows which strings change, in which direction and by how much, so you can see which strings stay put.
4. Work through the checklist, then do its recheck pass.
5. Play for ten minutes and recheck again. Strings that have just changed pitch keep settling for a while.

Neck relief over the next few days

The neck bows slightly forward under string tension, and the truss rod balances that pull. Change the total tension and the balance shifts. The strings react at once, but the wood keeps moving for hours or days.

• Lower total tension lets the neck straighten. Relief decreases, the action drops a little, and the strings can start to buzz.
• Higher total tension pulls more bow into the neck. The action rises and fretted notes in the middle of the neck go sharper.

Drop D changes one string and rarely needs anything. A tuning that lowers all six strings, such as half step down or whole step down, changes the whole load, and the neck notices. Give it a day, then check the action and tuning again before you reach for the truss rod. Switching back and forth between very different tunings every day keeps the neck from ever settling.

String gauges for low tunings

Tuning down with the same strings lowers their tension. A little is fine and some players like the looser feel. A lot makes the strings floppy: they buzz, the pitch wavers on the attack, and fretted notes tend to go sharp because a slack string stretches more when you press it.

The fix is a heavier set that brings tension back toward what you are used to. String makers publish tension charts for each gauge at each pitch. Look up the tension of your current set in standard tuning and choose a set whose tension in the new tuning comes out close to it. For very low tunings, a longer scale length helps too, because a longer string needs more tension to reach the same pitch with the same gauge. That is one reason baritone guitars exist.

Heavier strings bring their own adjustments. Nut slots cut for lighter strings can pinch the thicker ones and make them bind, and the intonation and relief both shift. Plan for a setup when you change gauge.

Floating tremolos need rebalancing

A floating tremolo balances string tension against springs. When you lower the strings, the springs win. The bridge tilts back, every string you already tuned goes sharp, and you chase the tuning round and round. When you raise the strings, the opposite happens.

• Expect many passes. Tune each string slightly past its target in the direction it has to travel, and the bridge movement will pull it back as you tune the rest.
• Once the strings hold, look at the bridge. If it no longer sits at its usual angle, adjust the spring claw in the back cavity: loosen its screws after tuning lower, tighten them after tuning higher. Retune after every adjustment.
• With a double-locking system, unlock the nut before a tuning change, tune, rebalance, lock, then finish on the fine tuners.

If you switch tunings often on a floating tremolo, consider blocking it or keeping a second guitar for the other tuning.

Recheck passes

One pass is never enough after a tuning change. On a fixed bridge with a small change, a recheck pass usually catches the last few cents. A big change needs two or three passes, and a floating tremolo can need more. Recheck again after the first few songs and again the next day, when the neck has caught up.

When to get a setup

Take the guitar to a tech when:

• You are changing to a tuning you plan to stay in.
• You change string gauge, especially going heavier.
• New buzzing appears, or the action changes noticeably after a day or two in the new tuning.
• The 12th-fret check from why guitars go out of tune shows fretted notes clearly sharp or flat.
• Strings ping or stick in the nut after a gauge change.
• A floating tremolo will not come back to balance.

A setup tunes the relief, action, nut slots and intonation to one tuning and one string set, and that is the condition in which a guitar plays and stays in tune best.

Keep a second guitar in the alternate tuning

If you play regularly in two tunings far apart, such as standard and drop C or an open tuning for slide, the most reliable solution is a second guitar. Each guitar gets strings and a setup that suit its tuning, each neck settles at one tension and stays there, and at a gig you swap guitars between songs instead of retuning in front of an audience. The guitar you rarely retune also stays in tune much more reliably.