Bass Tuner
← All toolsA four string bass sits at E1 41.20 Hz, A1 55.00 Hz, D2 73.42 Hz and G2 98.00 Hz; a five string adds a low B0 at 30.87 Hz underneath all of it. Tap a string to hear its pitch played back and tune by ear, or allow the microphone for live detection. The analysis window lengthens automatically down there, which is what makes a 31 Hz fundamental readable at all.
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Bass — 4-string (EADG)
| String | Note | Frequency | Reference tone |
|---|---|---|---|
| 4th | E1 | 41.20 Hz | |
| 3rd | A1 | 55.00 Hz | |
| 2nd | D2 | 73.42 Hz | |
| 1st | G2 | 98.00 Hz |
Tap Tone to hear a string and tune to it by ear — no microphone needed. Auto is on, so the needle below follows whichever string you are nearest.
Live pitch — microphone
Microphone audio is processed on-device and never leaves your browser — and the chart and reference tones above never need it at all.
How to use the Bass Tuner
- Select four or five string, then tap any string in the chart to hear its target pitch through your speakers or headphones.
- Allow microphone access if you want live readings, and play one string at a time with the others damped under your palm.
- Pluck gently over the neck pickup rather than hard at the bridge, because a soft pluck puts more energy into the fundamental and less into the harmonics that confuse a reading.
- Give the low strings a moment to settle, since the tuner needs several complete cycles of a slow wave before it can report a stable number.
Why low strings need a long analysis window
Autocorrelation works by sliding a copy of the incoming waveform against itself and finding the lag at which it best matches. That lag is the period, and the period inverted is the frequency. The method needs several complete cycles inside the buffer before it can call a match with confidence.
At the top of the bass that is trivial. G2 98.00 Hz repeats every 10 milliseconds, so even a short window already holds dozens of repetitions. At the bottom it is not. B0 30.87 Hz repeats roughly every 32 milliseconds and E1 41.20 Hz every 24, so the buffer has to grow to hold the same evidence. That is the tradeoff you feel as a slightly slower reading on the low strings — a longer window is the price of resolving a slow wave, not a fault.
Making the low B sound like a note
The B string is the one most likely to feel dead, and the cause is usually mechanical rather than a tuning error. B0 30.87 Hz on a 34 inch scale is a long, slack string; the same pitch on a 35 inch scale carries more tension at the same gauge, which is the entire reason longer scale five strings exist. Before blaming the tuner, check the following.
- Break angle over the nut and saddle. A B string that does not sit down firmly will rattle, and a rattling string reads as unstable pitch.
- Pluck strength. Hit it hard and it starts sharp, so wait for the note to settle before you judge the number.
- Order. Tune B first, work up to G2 98.00 Hz, then come back to B once the neck is carrying the full set of tension.
4-string and 5-string bass
The 5-string adds a low B a fourth below the E, at 30.87 Hz — low enough that most laptop and phone speakers cannot reproduce its fundamental at all, and low enough that it is the one note a short-window tuner gets wrong. Switch between the two in the picker above.
| Tuning | Strings, low to high | Frequency (Hz, A4 = 440) |
|---|---|---|
| Bass — 4-string (EADG) | E1 A1 D2 G2 | 41.20 55.00 73.42 98.00 |
| Bass — 5-string (BEADG) | B0 E1 A1 D2 G2 | 30.87 41.20 55.00 73.42 98.00 |
FAQ
- Will it detect the low B on a five string?
- Yes. B0 is 30.87 Hz, and the analysis window lengthens automatically when the tuner is looking that low. One cycle of a 30.87 Hz wave lasts about 32 milliseconds, so half a dozen cycles take roughly a fifth of a second of continuous audio — the window has to be long enough to contain them or there is nothing periodic to measure. Let the note ring rather than stabbing at it.
- Why does the reading jump to a note an octave up?
- Because a bass string's fundamental is weak next to its harmonics. Pluck hard near the bridge and the second or third partial can dominate the waveform, and a naive detector locks onto that instead. Autocorrelation on the normalized square difference function measures the repeat period of the whole wave rather than the loudest partial, which is why it holds the octave — but plucking softly over the neck pickup with the tone rolled back makes its job much easier.
- Should I tune through the amp or acoustically?
- Either, but keep the amp quiet. The microphone hears the room, so a cabinet pointed straight at the machine will overload the input and can start feeding back. Tuning acoustically works because the string itself is what the mic is reading, not the pickup. If your bass is very quiet unplugged, move it closer to the microphone rather than digging in harder, since a hard pluck bends the pitch sharp for the first moments.
- Do I need the microphone at all?
- No. Every string in the chart plays its own reference tone, so the whole instrument can be tuned by ear with the mic denied. One caution about playback: E1 41.20 Hz and B0 30.87 Hz are below what most laptop speakers can reproduce, so use headphones or a real speaker. Otherwise you will be matching a harmonic of the reference rather than the reference, and land an octave high.
