Online Double Bass Tuner

Fourths, not fifths — and geared tuners, not pegs

A double bass is tuned E1–A1–D2–G2, in perfect fourths rather than the fifths a violin, viola or cello uses — and those are the identical pitches as a standard 4-string electric bass. That’s deliberate history, not coincidence: the electric bass was built to stand in for the double bass and kept its open-string tuning on purpose. What’s genuinely different is how pitch gets set. A bass under full string tension at a 42-inch-plus scale length is impractical to hold with a friction peg the way a cello does — so basses were an early adopter, among the orchestral string family, of geared machine heads: worm-gear tuners, more like a guitar’s than a cello’s, giving up speed for precision.

How pitch is physically set

Each string winds onto a worm-gear machine head— a worm screw driving a toothed gear, the same principle as a guitar tuner rather than a cello peg. A worm drive gears down heavily and, by its nature, resists being back-driven by the string’s pull, which is what lets a bass hold pitch under this much tension without any friction fit at all. The practical result is that the pitch change per turn is small and predictable, so overshooting is hard. It's also why bass tuning is slower and more deliberate than tuning a violin-family instrument — there's no equivalent of a fast peg sweep followed by a fine tuner, because the gearing itself already does the fine-tuner's job. Some players still add an individual string adjuster at the tailpiece, most often on the E string alone, for pieces that call for retuning a string mid-performance without reaching up to the pegbox.

Tuning routine, step by step

1. Tune the A string first, at A1 = 55 Hz, matching the rest of the string section's reference pitch — orchestras commonly tune to 442 or 443 Hz rather than 440, so set concert A in the tuner settings before you start.
2. Move to E, then D, then G, turning the machine head slowly — the gearing means small turns produce small pitch changes, so there's no need to sneak up on a target the way a friction peg forces you to.
3. Give the low E real time to settle. It's the thickest string under real tension on the largest common orchestral instrument; bow or pluck it for a few seconds before trusting the reading, not the first attack.
4. Check the endpin before re-tuning anything that reads flat mid-piece. A double bass stands on a floor spike exactly like a cello, and a slipping or rocking endpin under bow pressure reads as flat pitch that has nothing to do with the tuning itself.
5. Re-check the A after the other three settle, since four strings under heavy tension over a floating bridge shift each other measurably as each one seats in.

Extending the range: C extension, 5-string basses and solo tuning

Orchestral repertoire occasionally asks for notes below the open E, and there are two standard ways to reach them. A C extension bolts onto the top of the fingerboard and mechanically lengthens the E string itself down to C1, a fourth below open E — modern versions use machined "stops" that clamp the string at D1, C♯1 and C1 so those notes are reliably reachable without hand-stopping the string behind the scroll. The alternative is a genuine 5-string bass with a low B0 string added below the E — heavier and pricier than adding an extension, but avoiding the extension's own upkeep and the slight added string length it puts above the nut. In practice B0 is needed rarely enough in the standard repertoire — Richard Strauss's Also sprach Zarathustra is close to the only standard orchestral piece that actually asks for it — that the choice between the two usually comes down to which mechanism a player prefers to live with, not which range they need more often.

Solo tuning — every string raised a whole step, F♯1–B1–E2–A2 — is a different kind of range extension: not lower notes, but a brighter, more penetrating tone for concerto and solo repertoire, a practice that traces back to 19th-century virtuosi like Giovanni Bottesini. It requires its own dedicated string set, not a standard set cranked up; see the warning above for why.

Equal temperament vs. tuning by ear

A pure fourth and an equal-tempered fourth differ by about 2 cents — roughly the same small gap that separates a pure fifth from an equal-tempered one, the reason violin, viola and cello players commonly fine-tune their open strings by ear against each other rather than against a fixed grid. Double bass hasn't developed that same by-ear tradition to the same degree; in practice, most players — like electric bassists — tune each string directly against an equal-tempered reference and treat that as correct, since a 2-cent gap is smaller than the pitch variation that comes from technique, temperature or a settling string on an instrument this size. Our guide to cents covers where that 2-cent gap actually comes from.

Frequently asked questions