Online Reference Pitch

What this is — and what it is not

• A digital tuning fork plus an ear-training bench: it emits reference pitches, and it can play a second tone against them so you can practise hearing and killing a detuning.
• This widget does not listen to your instrument. There is no microphone, no pitch detection, no analysis of anything you play. Every number on the page is computed from the pitch it is generating. Your ear does the comparison.

Hero readout

• Big number = the exact frequency of the selected pitch at the current A4 reference. It changes the instant you move the calibration.
• The line underneath shows the reference in use and how far the sounding pitch sits from its A440-standard value, in cents.
• Play tone / Stop tone starts and stops the sustained reference. The dot pulses while sound is going out.
• − semitone / + semitone steps one half step and crosses octave boundaries automatically.

A4 calibration — and what it costs

• Slider or number box, 415–466 Hz in 0.5 Hz steps, plus one-tap chips for the common conventions. While a tone is sounding the pitch glides smoothly as you drag, so you hear the calibration move.
• The little meter marks where you are between 415 and 466, with a tick at 440. Under it, the live cents line shows the difference between your A4 and the A440 standard: 442 is +7.9 ¢, 432 is −31.8 ¢, 415 is −101.3 ¢ — a whisker over a full semitone flat. That offset applies to every pitch on the page equally.
• Convention used: twelve-tone equal temperament, MIDI note 69 = A4 = the reference you set. Every frequency here is f = A4ref × 2^((n − 69) / 12). At A4 = 440 that gives C4 = 261.63 Hz.

Same note, three references

• Three live cells show the selected note at baroque 415, modern 440 and orchestral 442 Hz, each with its cent offset from the 440 value. Tap a cell to switch the whole widget to that reference and hear the difference.

Pitch ladder

• Octave row (0–8): tap a number to move the whole ladder up or down an octave.
• Twelve pitch buttons (C → B): tap one to select and immediately sound it. Each button prints its own live frequency, so you can watch every pitch shift when the calibration moves.
• Octave numbering is scientific pitch notation and rolls over at C: B3 is the note directly below C4, and C4 is middle C.

Instrument & strings

• Pick an instrument in the top row; the row underneath becomes that instrument's open strings or tuning notes, each with its live frequency. Tap a string to select and sound it.
• Tunings used (shown at A4 = 440; they all move with the calibration):
  • Violin G3 196.00 · D4 293.66 · A4 440.00 · E5 659.26
  • Viola C3 130.81 · G3 196.00 · D4 293.66 · A4 440.00
  • Cello C2 65.41 · G2 98.00 · D3 146.83 · A3 220.00
  • Double bass (fourths) E1 41.20 · A1 55.00 · D2 73.42 · G2 98.00
  • Guitar (standard, 6th→1st) E2 82.41 · A2 110.00 · D3 146.83 · G3 196.00 · B3 246.94 · E4 329.63
  • Bass guitar (4-string, 4th→1st) E1 41.20 · A1 55.00 · D2 73.42 · G2 98.00
  • Ukulele (soprano/concert, GCEA) G4 392.00 · C4 261.63 · E4 329.63 · A4 440.00. This is re-entrant tuning: the 4th string G4 is higher in pitch than the 3rd string C4, so the strings do not run low-to-high across the neck.
  • Mandolin (same as violin) G3 196.00 · D4 293.66 · A4 440.00 · E5 659.26
  • Banjo (5-string open G, gDGBD) g4 392.00 · D3 146.83 · G3 196.00 · B3 246.94 · D4 293.66 — also re-entrant: the short 5th string g4 is the highest of the five.
  • Winds & brass concert tuning notes: A4 440.00 (oboe A) · B♭3 233.08 (B♭ trumpet/clarinet written C) · B♭4 466.16 · F4 349.23 (horn) · C4 261.63 · E♭4 311.13 (E♭ instruments' written C).
  • Pitch standards set the A4 calibration as well as the note: piano 440, flute 442, orchestra 443, baroque 415.
  • Octave A's A1 55.00 · A2 110.00 · A3 220.00 · A4 440.00 · A5 880.00 — handy for checking octaves.

Tuning pass (auto-cycle)

• Start tuning pass walks the chosen instrument's strings in order, holding each one for the dwell time you pick (1.5 / 2.5 / 4 / 6 seconds) with a short gap between, then loops back to the first string. Hands stay on the pegs.
• Every note change is scheduled against the audio clock, not a page timer, so the dwell times stay even even if the tab is busy.
• The line under the buttons tells you which string is sounding and its position in the pass. Press the button again, or press Stop tone, to end it.

Beat lab

• Start beat lab sustains the reference (tone A) and adds a second pure sine (tone B) offset from it in hertz.
• When two tones are close but not identical you hear the loudness swell and dip — those are beats, and the beat rate in beats per second is exactly the frequency difference in hertz. 3 Hz apart = 3 wobbles a second. At unison the wobble stops dead. The big number and the pulsing bar both track it live.
• Slide the offset, or use the −1 / −0.1 / Unison / +0.1 / +1 Hz buttons for fine work. The line at the bottom prints tone B's actual frequency and how far off it is in cents, which is different at every pitch: 1 Hz is about 4 cents at A4 but about 42 cents at E1.
• Tone B is always a sine, because beats are clearest between simple tones. Setting tone A to Sine as well makes them cleaner still.

Detune trainer

• New round sounds the reference and adds tone B somewhere from 0 to 40 cents above or below it (occasionally dead in tune).
• Step 1: call it — Flat, In tune, or Sharp. Anything within 2 cents counts as in tune.
• Step 2: null it. Slide tone B, or use the nudge buttons, until the beating stops. The beat readout is deliberately hidden here — you get no numbers, only your ears. Lock it in when the wobble is gone.
• You are then scored on how many cents you were still off, the true offset is revealed, and the direction call is marked. Under 5 cents with the direction right extends your streak; 5 cents is roughly the point where a tuned unison starts to sound clean.
• The five tiles keep Rounds, current Streak, Best streak, Best null (your smallest ever residual) and Avg miss across the session. End session silences tone B; Reset clears the scores.

Timbre, length, volume

• Sine is a single pure partial — the cleanest thing to tune against. Tuning fork adds faint 6th and 7th partials for the shimmer a real fork has. Reed stacks partials 1–8 like an oboe A, which is easier to hear across a room. Drone is organ-like — fundamental, octave, twelfth and fifteenth — warm enough to sit under for a long session. The bar chart shows the actual partial amplitudes in use.
• Hold sustains until you stop it. Blip gives a short tone that fades itself out. Drone sustains too, switches the timbre to the drone wave and adds a very slow breathing swell (about one cycle every 7 seconds) so a long-held reference stays alive rather than going flat and fatiguing. You can still change the timbre while in Drone.
• Volume defaults to 25%. All level changes are ramped, so nothing pops.

Mouse & touch

• Click or tap any pitch, octave, string, reference cell or chip — every one of them sounds as well as selects.
• Drag the calibration, volume, beat-offset and trainer sliders; the number box accepts typed values.

Keyboard

• Space — play / stop the reference tone.
• ← / → — move down / up one semitone (and sound it).
• ↓ / ↑ — move down / up one octave (and sound it).
• Tab to reach any control, then Enter or Space to fire the focused pitch, string, chip or trainer button.
• Arrow keys are left alone while a slider or the number box has focus, so those behave normally.

Tips

• Tune to the pitch your instrument really has, not the concert pitch you read: a B♭ trumpet playing its written C sounds concert B♭3 = 233.08 Hz, which is in the winds group here.
• Listen for beating rather than pitch. Play the reference, play your string, and slow the wobble until it disappears — that is easier and far more accurate than judging "high or low". The beat lab lets you rehearse the sensation without an instrument in your hands.
• Only one of the tuning pass, the beat lab and the trainer runs at a time — starting one ends the others, because they all share the same second voice.