Quick Start

Sing your first in-tune interval in 60 seconds.

Open the app and enable your microphone

Open Intonation Lab in any modern browser (Chrome, Firefox, Safari, or Edge). Click the green Enable Microphone button in the Singing HUD card. Your browser will ask for microphone permission — click Allow.

Singing HUD card with Enable Microphone button

Headphones recommended. Wearing headphones prevents the reference tone from feeding back into your microphone, which can confuse the pitch detector.

Using a USB mic or audio interface? In Advanced mode, the Settings panel has Input and Output dropdowns. Select your USB mic as input and your headphones as output so the reference tone goes to your ears while the mic picks up only your voice.

First time? An interactive tour will guide you through the key areas of the app on your first visit. Follow along or click Skip tour to jump right in.

Pick an interval to practice

Use the interval dropdown to select which interval you want to sing. Perfect 5th is a great starting point — it's one of the most consonant intervals, so the "in tune" sweet spot is easy to hear.

Header bar with Perfect 5th selected in interval dropdown

The app starts in Basic mode, which shows only intervals. Switch to Advanced mode (the Adv toggle in the header) if you want access to chords, the training curriculum, and all visualizations.

Play the reference tone

Press and hold the Hold to play button to hear the reference tone and your target note together. This gives you a pitch to aim for. You can also switch to Sustain mode so the tone plays continuously while you sing.

Tone playback card with Hold and Sustain buttons

Try different timbres. The timbre dropdown lets you switch between sine wave, instruments, and vocal tones. Hearing the reference in a voice-like timbre (e.g., "Voice M ah") can make it easier to match.

Compare JI vs ET. Press the Compare JI / ET button to hear the same interval in both tuning systems back to back. This makes the difference between pure and tempered intervals immediately obvious.

Sing and watch the beat circle

Sing the target note while watching the beat circle visualization. The circle pulses at the beat rate between your voice and the target pitch:

Fast pulsing (red) — you're far from the target
Slow pulsing (amber) — getting closer, keep adjusting
Still and glowing (green) — you're in tune!

Beat circle pulsing amber at 3.2 beats per second

Focus on the beats, not the numbers. The cents display and gauge are helpful, but the beat circle gives you the most intuitive feedback. When two close pitches sound together, you hear a "wobbling" or "throbbing" — that's beats. Your goal is to make the beats slow down until they stop. This is how singers and instrumentalists have tuned for centuries.

See "In tune!"

When you lock in, the circle goes still and glows green, and the label reads "In tune!". The cents display drops to near zero. Congratulations — you've just sung a pure just intonation interval!

Beat circle glowing green with In tune label

Hold the pitch steady and listen. That pure, beatless sound is what just intonation sounds like. The longer you can hold it, the better your ears and muscles will remember it.

What next?

Try other intervals — Start with Perfect 4th and Octave, then move to Major 3rd (where you'll really hear the difference from piano tuning).
Switch to Advanced mode — Unlock chord types, the cymatics and pitch tracker visualizations, sensitivity controls, and the full settings panel.
Follow the training curriculum — In Advanced mode, click Train to enter guided training. The app walks you through 52 exercises at increasing difficulty.
Read the full documentation — The documentation covers every feature, explains the audio concepts behind just intonation, and includes tips for improving your singing accuracy.
Record and review — Use the Record button in the Singing HUD to capture a practice session, then hit Playback to review your pitch accuracy on the tracker.
Enable the drone — In the Tone card, turn on the Drone (Root or Root+5th) for a continuous reference pitch while you sing.
Try dark mode — Click the sun/moon icon in the header to switch between light and dark themes.
Try it free first — Don't have an access code yet? Click Try Free Demo on the login page to explore with three intervals (Unison, Perfect 5th, Octave) for 3 minutes per day.