Bass Guitar Tuner
Tune a four, five or six-string bass. Built for low fundamentals - a low B at 31 Hz is detected as the note it is, not its octave.
Let the note ring. A low B takes far longer to analyse than a guitar string — its wave is over ten metres long and the tuner needs a couple of full cycles before it can answer. Pluck gently over the neck rather than hard by the bridge: a hard pluck near the bridge is mostly harmonics, which is exactly what makes a lesser tuner report the octave above.
Press start, then play a note.
The microphone is used only while you are tuning. Nothing is recorded and no audio leaves your device.
Tap a string to tune it on its own, or tap it again to hear its reference note. Leave none selected and the tuner will work out which string you played.
A4 = 440 Hz is the international standard and the right default. Some ensembles tune slightly differently by convention; no reference pitch is acoustically or scientifically superior to another.
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Microphone not working? Check it with the microphone test. Hearing nothing from the reference tones? Try the sound test.
Why bass tuners get the octave wrong
A plucked bass string is not loudest at its fundamental. The second harmonic - exactly an octave up - is very often louder, and on a low B through a small speaker the fundamental can be the quietest thing present. A tuner that reports the loudest frequency it finds therefore tells you that your low E is an E, one octave too high, and you tune confidently to the wrong note.
This tuner measures the period of the waveform rather than looking for the loudest partial, and it deliberately takes the longest true period rather than the strongest peak. That is what makes a 31 Hz low B read as a low B.
Let it ring, and pluck gently
Low notes take genuinely longer to measure. A 31 Hz wave is over ten metres long, and the tuner needs a couple of complete cycles before it can say anything - roughly a fifth of a second, against a fraction of that for a guitar's top E. Give it a moment.
Pluck softly and over the neck rather than hard by the bridge. A hard bridge pluck is mostly harmonics with very little fundamental, which is precisely the signal that confuses pitch detection. A soft neck pluck is the opposite.
Five and six string
The low B on a five-string sits at 30.87 Hz, below the bottom of most speakers and many microphones. If your phone struggles with it, tune the B string using the reference tone and your ear, or tune it at the twelfth fret harmonic where the frequency is doubled and far easier for everything involved to hear.
Drop tunings
Drop D takes the low E down a whole tone; drop C takes the whole instrument down a tone and then the low string down another. Both are here, and both retarget the detector so the lowest string is not compared against the wrong note.
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Quick answer
Choose your string count and tuning, press start and play a string. Let low notes ring - a low B needs a couple of full cycles before the tuner can answer. Pluck gently over the neck rather than hard by the bridge.
Key facts
- 4, 5 and 6-string standard plus drop D, drop C and half step down
- Detects a 31 Hz low B correctly
- Larger analysis window than the guitar tuner, for low fundamentals
- Picks the true period rather than the loudest harmonic
- Reference tone for every string