Free online bass tuner

A bass plays the lowest notes in the band, and its low strings sit right at the edge of what small microphones and many tuners can hear. This tuner listens for notes down to the low B of a five-string bass, about 31 Hz, so it reads the whole instrument. Below is what each string should read, how to tune a four-string and a five-string bass, drop D, and what to check when the reading jumps around.

Standard bass tuning: E A D G

A four-string bass is tuned E A D G, from the thickest string to the thinnest. Those are the same note names as the four lowest strings of a guitar, an octave lower, so a guitarist already knows the layout. At the standard reference pitch, A = 440 Hz, the frequencies are:

Each string is a perfect fourth, five frets, above the one below it. That even spacing is what makes bass shapes movable: a pattern you learn starting on the E string works the same starting on the A string.

Why low notes are hard to tune

The low E of a bass vibrates 41 times a second. To measure a pitch, a tuner needs to hear a few complete cycles of it, which at 41 Hz takes a long stretch of sound. Many tuners built for guitar stop at around 60 or 70 Hz and see only the overtones of a bass string. This one switches to a longer listening window for the bass presets, so it measures the string itself.

The microphone is the other limit. Laptop and phone microphones are small and pick up very little below about 80 Hz, so most of what they hear from a bass is its overtones. The tuner works out the pitch from the pattern those overtones repeat in, and it still reads the right note. It helps to hold the bass close, pluck firmly and let each note ring for a second or two. A bass plugged into an amplifier gives a stronger signal than an unplugged one.

Tuning step by step

1. Sit or stand as you play, so the neck is at playing tension, and keep the room quiet.
2. Start with the E string. Pluck it firmly with your finger near the end of the neck and watch the reading.
3. If the reading is flat, tighten the machine head. If it is sharp, loosen it below the note and come back up.
4. Tune the A, D and G strings the same way.
5. Check all four once more. Large changes on one string move the others slightly through the neck.

If a string is far out, the tuner can mistake it for its neighbour in Auto mode. Tap the string’s button to switch to Manual and aim at that string only, bring it close, then tap again to return to Auto.

5-string bass: adding a low B

A five-string bass adds a low B below the E: B0, E1, A1, D2, G2. The B string is 30.87 Hz, five notes below the E, and the other four strings are tuned exactly as on a four-string bass. Choose 5-string in the Tuning menu so the tuner expects the extra string. The low B is the hardest string to tune by microphone, so play it firmly and give the reading a moment to settle.

Drop D on bass

Drop D lowers only the E string, a whole step, to D1 at 36.71 Hz. It gives a four-string bass one more low note and matches a guitarist playing in drop D. Choose Drop D in the Tuning menu, tune the E string down until it reads D, and leave the other three strings where they are. To check it by ear, the open D string should sound exactly one octave above the new low D.

Tuning by ear: the fifth-fret method

A bass can also be tuned to itself. With the E string in tune, press it at the fifth fret: that note is A, and it should match the open A string. Press the A string at the fifth fret to tune the D string, and the D string at the fifth fret to tune the G string. On a five-string, press the B string at the fifth fret to match the open E. When two notes are close but not equal, the sound wobbles slowly; turn the machine head until the wobble stops. A steady reference note such as the E tuning drone sets the first string.

When the reading jumps around

• Old strings. Worn bass strings lose their overtones and sound dull, which makes the pitch hard to read and hard to hear. If the note dies within a second, the strings are due.
• Fret buzz or a muted string. A string that buzzes against a fret gives a noisy, unsteady reading. Pluck closer to the neck and let the string ring freely.
• Background noise. A drum kit, an amp hum or a fridge can sit close to bass frequencies. Tune in a quiet room or close to the microphone.
• Intonation. If the open strings are in tune but notes higher up the neck sound off, the saddles need adjusting. Compare the twelfth-fret note with the open string an octave below; they should agree.

After tuning

With the bass in tune, the list of bass songs for beginners has the first bass lines to learn, each linked to its sheet music on MuseScore. The online metronome keeps them in time while you practice.