How to tune a mandolin

A mandolin has eight strings, four pitches and a total tension high enough that everything on the instrument is under strain. Tuning it is not difficult, and it is fiddly in a specific way that catches out anyone arriving from guitar.

The layout

Eight strings arranged as four courses — pairs of two strings tuned to the same note. Picking a course strikes both, and the tiny differences between them are what give a mandolin its shimmer.

From the thickest course to the thinnest: G, D, A, E. That is identical to a violin, which means violin and mandolin players can read each other’s music directly and any fiddle tune transfers without transposition.

A Kentucky KM-150#ad is a standard A-model instrument with this arrangement, and the tuning is the same across every mandolin body style.

Why unison pairs are unforgiving

Here is the part that makes mandolin tuning different from anything else on this site.

Two strings tuned to almost the same note produce beating — a pulsing wobble in the sound as the two waves drift in and out of phase. The closer they get, the slower the pulse. When they match exactly, it disappears.

That means a mandolin can be perfectly in tune against a tuner on every string and still sound wrong, because a course that is a hair apart wobbles. It also means you have a very precise tool available: your own ears can hear the beating stop far more accurately than most tuners can resolve.

The practical method is a hybrid. Tune the first string of each course with the tuner, then tune its partner to it by ear, listening for the beating to slow and vanish.

The order that converges fastest

Eight strings at high tension all pull on the same bridge and the same neck. Tighten one and the others go slightly flat. Work in a bad order and you chase yourself for ten minutes.

Do a rough pass on all eight first. Get everything approximately right before trying to get anything exactly right. This is the step most people skip.

Then work from the inner courses outward. D, then A, then G, then E. The middle courses sit near the center of the bridge and disturb the overall balance least.

Then do it again. A second full pass will find that everything has moved slightly. That is normal. A third pass is usually very quick.

Tune up to the note, never down to it. Approaching from below takes up the slack in the tuner gears and along the string. A string tuned downward to pitch drifts flat almost immediately.

Use a clip-on tuner

A Snark clip-on chromatic tuner#ad clips to the headstock and reads vibration through the wood rather than through a microphone, which matters on a mandolin because you are frequently tuning in a room with other instruments in it.

One practical point: mute the partner string while tuning its neighbor. Two strings very close in pitch confuse a tuner badly, and the display jumps around. A finger resting on the string you are not tuning solves it entirely.

The floating bridge

A mandolin bridge is not glued down. It is held in place by string tension alone, exactly like a violin bridge, and it can move.

If it shifts toward the neck or the tailpiece, the instrument will tune perfectly on open strings and be noticeably out of tune everywhere up the neck, because the string length is wrong.

Check it by comparing the twelfth-fret harmonic against the note fretted at the twelfth fret. If the fretted note is sharp, the bridge needs to move slightly away from the neck; if it is flat, slightly toward it. Slacken the strings a little before nudging it, and move it in very small increments.

Never take all eight strings off at once. With no tension, the bridge falls over, and putting it back in exactly the right place is a job you have now created for yourself. Change strings one course at a time.

When a course will not settle

New strings. They stretch for several days. Expect repeated retuning and do not diagnose anything until they have settled.

Untidy winding at the tuner. Coils that stack on top of each other compress under tension, which reads as the instrument going flat. Wind neatly, downward along the post.

A binding nut slot. If a string goes sharp in jumps as you turn the tuner, it is sticking in the nut and then releasing. A tiny amount of pencil graphite in the slot usually frees it.

One string of a pair that will not hold. Frequently a string that is about to break, particularly on the thin E course. Keep spares.

How long this should take

For a beginner, five minutes with the tuner and two or three passes. That is normal and not a sign of anything wrong — eight strings at high tension simply take longer to settle than four.

Experienced players get it down to a minute, mostly by doing the rough pass quickly and trusting their ears for the unisons.

Which mandolin to buy in the first place is in best beginner mandolins, and if you are still choosing between small fretted instruments, see mandolin or ukulele.