Bass Tuner
A bass tuner that opens on the four strings E1 A1 D2 G2, listens through your microphone, and shows how far each string is from pitch. Press a string to hear its reference tone and tune by ear instead. The detector reaches down to the low E at 41 Hz, and to a five-string's low B, and measures pitch from the raw samples in the page: nothing is recorded, nothing is uploaded, and the microphone is released the moment you stop. Switch the Tuning control to Standard, Drop D or Half step and the same page tunes a guitar.
Tune with your microphone
Your browser asks for permission first, because no page may listen without it. The samples are read in the page and dropped: nothing is recorded and nothing is uploaded.
The microphone is closed. Press Start to tune with it, or Play to hear a reference tone.
Strings in each tuning
Every frequency here is at A = 440, the reference chosen above, and is the exact pitch the Play button sounds. Any string is tuned the same way: play it, watch the bar, and turn the peg until the needle sits in the green. Sharp means the string is too tight, so tune down; flat means too loose, so tune up.
| Tuning | Strings, low to high | Frequencies |
|---|---|---|
| Standard | E2 A2 D3 G3 B3 E4 | 82.4 Hz, 110.0 Hz, 146.8 Hz, 196.0 Hz, 246.9 Hz, 329.6 Hz |
| Drop D | D2 A2 D3 G3 B3 E4 | 73.4 Hz, 110.0 Hz, 146.8 Hz, 196.0 Hz, 246.9 Hz, 329.6 Hz |
| Half step down | Eb2 Ab2 Db3 Gb3 Bb3 Eb4 | 77.8 Hz, 103.8 Hz, 138.6 Hz, 185.0 Hz, 233.1 Hz, 311.1 Hz |
| Bass | E1 A1 D2 G2 | 41.2 Hz, 55.0 Hz, 73.4 Hz, 98.0 Hz |
Common questions
- Why does a bass string take a moment to settle on the tuner?
- A low string repeats slowly: the open E on a bass is 41 Hz, so each frame the detector looks at holds under four cycles of it, against more than twenty for a guitar's top string. Fewer cycles means room noise moves the reading more, and the first instant after the pluck, while the string is still settling, reads unsteadily on any tuner. Pluck firmly, let the string ring on its own, and read the needle a second in. Above about 80 Hz the reading resolves to around a cent; on the E and A strings allow it a few cents of wander and trust where it settles.
- Should I tune a bass with the harmonic at the 12th fret?
- It helps on the lowest strings, because the harmonic is an octave up, cleaner and steadier than the open string, and a tuner reads it more sharply. Touch the string lightly over the 12th fret wire, pluck, and lift your finger: the note name will show one octave higher, E2 for the E string. The bar is measured against the nearest of the four open strings, and E2 is nearer to the D string than to the E an octave below it, so on a harmonic read the note name and the frequency under it rather than the bar: at A = 440 the harmonics are E2 at 82.4 Hz, A2 at 110.0, D3 at 146.8 and G3 at 196.0. In tune on the harmonic is in tune on the open string.
- Does it handle a five-string bass with a low B?
- The four chips are E A D G, so the bar and the sentence are measured against those four. The low B is 30.9 Hz at A = 440, right at the bottom of what the detector hears, and it will name the note as B0 when it locks on, but the cents bar will be showing the distance to the E string rather than to B. Tune the B by its 12th fret harmonic instead: that is B1 at 61.7 Hz, which the detector reads steadily, and use the note name and the frequency readout under the note rather than the bar.
- Does it work with a bass plugged straight in, without a microphone?
- Yes, if the bass reaches the browser as an input. A USB audio interface, or a USB cable from an amplifier or pedal that presents itself as a sound device, appears in the Input list once the microphone has been allowed, and choosing it reopens the stream on that input. A direct signal is cleaner than a microphone in front of an amp and reads faster. What cannot work is a plain instrument cable into a laptop's microphone socket, which expects a microphone level and usually a different plug.
- Which way do I turn the peg when the tuner says sharp?
- Sharp means the string is sounding higher than it should, so it is too tight: loosen it, which the tool calls tune down. Flat means too loose: tighten it, tune up. On a bass the pegs are large and each turn moves the pitch a long way, so move in small steps and let the string ring after each. If a string is a long way out, the line under the note switches from a touch to the number of cents and the direction, so a string a whole tone flat is called 200 cents flat of E1, tune up, rather than a touch.
Pitch is measured from the raw microphone samples with autocorrelation, which resolves to about one cent for notes above 80 Hz in a quiet room; background noise and a decaying string widen that. Reference tones are exact. No audio is recorded or sent anywhere.