Open G minor tuner: D G D G Bb D, free, with your mic

This is a free online guitar tuner, already set to Open G minor. The strings become D G D G Bb D, and the open strings ring out a G minor chord. If you are already in Open G, only one string moves. Press Start, tap the button of the string you are tuning, play it, and turn the peg until the reading sits at 0 cents. Open G and standard are in the menu above the tuner. No account, no download. It sits alongside the rest of our free guitar tools.

What Open G minor tuning is

An open tuning is one where the open strings already form a chord. Open G minor is built on G minor: G is the root, Bb the minor third, D the fifth. Count the strings and you find three Ds, two Gs and one Bb, a complete chord with its fifth doubled. The lowest string is one of those Ds rather than the root, exactly as in Open G.

From standard tuning, four strings go down and two stay where they are. Three of the four drop a whole step; the second string drops only a half step. Nothing goes up, so the guitar ends up under less tension than it started with.

The tuner writes the second string Bb, never A#: this preset names notes with flats, which is how they are spelled in G minor. The reference pitch menu offers A at 432, 440 and 442 Hz, and opens on 440, which is what the frequencies above assume.

One string away from Open G

Open G minor is Open G with a single change. In Open G, D G D G B D, the second string is B, the major third of the chord. Lower it a half step to Bb and the third turns minor. The other five strings do not move, which is why players who already live in Open G can switch in a few seconds and back again.

1. Get the guitar in Open G first. The Open G tuner walks you through it from standard.
2. Press Start here. The tuner is on Open G minor, so the second string's target is Bb3, 233.08 Hz.
3. Play the second string. A B sits a half step above Bb, close enough for the tuner to recognize it on its own: it reads about 100 cents sharp and tells you to loosen.
4. Loosen slowly until the reading sits at 0 cents.

How to tune to Open G minor from standard

Starting from standard tuning, there are four strings to lower, and they do not all behave the same way on the tuner.

1. Press Start and allow the microphone. The tuner is already on Open G minor.
2. Tap the button for the sixth string, D2, before you turn its peg. In automatic mode the tuner only locks onto a string within a little less than a whole step, so a low E that has not moved yet is read as an E, and an E in tune looks like good news. With the button tapped, the tuner aims at D2 and tells you to loosen.
3. Do the same for the fifth string, G2, and the first, D4. Both drop a whole step, so tap each button first.
4. The second string needs no button. It only drops a half step, from B to Bb, and the tuner locks onto it by itself.
5. Go round all six strings a second time. Four strings losing tension lets the neck relax a little, and the others drift while you work.

There is an ear check for each step, useful when you have no tuner at hand. In Open G minor the gaps between strings are 5, 7, 5, 3 and 4 frets, reading upwards. The fifth fret of the sixth string gives the open fifth, the seventh fret of the fifth gives the open fourth, the fifth fret of the fourth gives the open third, the third fret of the third gives the open second, and the fourth fret of the second gives the open first.

Chords in Open G minor: one finger across the neck

Because the open strings are a G minor chord, laying one finger flat across the strings at any fret gives you another minor chord, in tune, with no shape to learn. The chord moves up one half step per fret.

As in Open G, the sixth string carries the fifth of the chord, not the root. Strum all six for the wide, droning sound; start from the fifth string when you want the chord planted on its root.

Major chords need one adjustment. The third of the chord sits on the second string, so fret that string one fret above the barre and the minor third becomes a major third. In the open position, the first fret of the second string turns Bb back into B and gives you G major.

A capo works normally and changes the key without retuning. At the third fret, the open strings sound Bb minor.

These diagrams are drawn for Open G minor, not for standard tuning. Read the open strings as D G D G Bb D: the same shapes in standard would give different chords.

A minor blues in Open G minor

A minor blues in G turns on three chords, and this tuning hands you all three with one finger: G minor at the open strings, C minor at the fifth fret, D minor at the seventh. Here is a common twelve bar form.

Many minor blues play the ninth bar as D major rather than D minor, for more pull back home. Barre the seventh fret and press the second string one fret higher, at the eighth: Bb becomes F#, and the chord turns major.

• With a slide, sit it directly over the fifth or seventh fret, not between frets, and rest it on the strings with almost no pressure.
• Mute behind the slide with the trailing fingers, or the strings between the slide and the nut ring along.
• Fingerpicking, let the open strings carry on as a drone and bring the Bb out in the melody: it is the note that makes the tuning minor.
• Start slow. Set a metronome at a tempo where every chord change lands cleanly, and only then speed up.

Open D has a minor version too, one string away from it in the same way: Open D minor, D A D F A D. For every other preset, go to the online guitar tuner, and if tuning by ear is new to you, how to tune a guitar is the place to start.