Bass Tuner (4, 5 and 6 String)

Tune a bass guitar three ways: let the live tuner listen through your microphone and show how many cents each string is off, play reference tones and tune by ear, or check a recording of one string. It covers 4-string (E A D G), 5-string with a low B or a high C, 6-string, drop D, half step down and D standard. Bass notes are low, so the tuner measures over windows of about 0.19 s, long enough for the 31 Hz low B. The sound is analysed in your browser and never recorded or uploaded.

How to use this tool

1. Choose your bass and tuning.
2. Live: press Calculate, allow the microphone and pluck one open string at a time, muting the others; turn the peg until the bar is centred and green.
3. By ear: press Calculate and play each reference tone through headphones or a speaker with real bass.
4. Recording: choose "Check a recording", pick the file and press Calculate.

Formula

f = A4 × 2^((n − 69) ÷ 12) · cents = 1200 × log2(f_played ÷ f_string)

n is the MIDI note number. At A4 = 440 Hz the standard bass strings are E1 41.20, A1 55.00, D2 73.42 and G2 98.00 Hz; a low B is B0 30.87 Hz and a high C is C3 130.81 Hz. Pitch is measured with the YIN method from 25 Hz to 1 kHz. A note more than a fifth above the highest string, or more than three semitones below the lowest, is reported as outside the bass range; this usually means the tuner caught an overtone. Within ±3 cents counts as in tune.

Example

Your A string sounds at 54.6 Hz instead of 55.00 Hz. That is 1200 × log2(54.6 ÷ 55) = −12.6 cents: flat, so tighten the string slightly. A low B at 30.87 Hz completes only about 6 cycles in the 0.19 s window, which is why bass tuners need longer windows than guitar tuners.