Train your ear to sing in perfect tune
Pianos are tuned to a compromise. Voices don't have to be. Intonation Lab teaches your ear to hear and produce the pure intervals that make chords ring — using real-time pitch detection, just intonation targets, and visual feedback you can see and feel.
Intonation Lab is a browser-based ear training tool for singers, created by Ted Chamberlain. It uses real-time pitch detection to help singers develop precise intonation using just intonation — the pure tuning system based on natural harmonic ratios. Features include 13 intervals, 7 chord types, 13 timbres, a beat frequency visualization, cymatics display, pitch tracker, and a 52-exercise guided curriculum. Pricing starts at $99 for individuals, with group licenses up to $999 for choruses.
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Pianos are out of tune. On purpose.
Every piano in the world uses equal temperament — a tuning system that slightly detunes every interval so all 12 keys sound equally acceptable. It's a practical compromise, and for keyboards it works well enough.
But singers aren't keyboards. When you sing a major third that matches a piano, you're actually 14 cents sharp of the pure, resonant interval. When a barbershop quartet or choir locks into a chord that rings with an almost physical buzz, they're singing in just intonation — pure ratios that equal temperament can only approximate.
When a chord locks in, you can feel it. That's just intonation.
The challenge is training your ear to hear and produce these pure intervals reliably. That's what Intonation Lab is built to do.
What's inside
Six core capabilities that work together to build your intonation skills — from hearing the difference to singing it consistently.
13 Intervals + 7 Chord Types
Practice any interval from unison through octave, or choose from major and minor triads, dominant 7th, major 7th, minor 7th, diminished, and augmented chords. Each target is calculated using just intonation ratios.
Beat Frequency Circle
A pulsing ring that wobbles at the actual beat rate between your voice and the target. Still and green when you're in tune, wobbling red when you're off. Learning to see and hear these beats is one of the most powerful ways to develop intonation.
Cymatics Visualization
A mandala-like geometric pattern that stays stable and symmetric when you're in tune, then rotates and distorts as you drift. A beautiful way to visualize acoustic consonance in real time.
13 Timbres
Hear your reference pitch as sine wave, oboe, violin, piano, organ, trumpet, flute, or six vocal timbres (male and female "oo," "ah," and "ee"). Each with a unique harmonic profile to train against.
Pitch Tracker
A scrolling line chart that records your pitch over time, showing your trajectory toward the target. See whether you approach from above or below, and how stable your pitch is once you find it.
52-Exercise Curriculum
A guided training system that progresses from easy intervals to hard ones, at increasing accuracy requirements. Four difficulty levels from beginner (±25 cents) to expert (±5 cents). Progress tracking and diagnostic feedback after each exercise.
How it works
Choose your interval or chord
Select any of 13 intervals (unison through octave) or 7 chord types. The app calculates the exact just intonation target frequency.
Enable your microphone
Grant microphone access and Intonation Lab starts analyzing your pitch in real time using autocorrelation-based detection.
Sing and watch the feedback
The beat frequency circle, cents gauge, cymatics pattern, and pitch tracker all respond instantly. Color shifts from red to amber to green as you approach the target.
Train with the guided curriculum
Follow 52 structured exercises that progressively challenge your ear. Track your progress across all intervals and difficulty levels.
Choose your license
Individual access or group licenses for quartets, ensembles, and choruses. All access codes are delivered instantly by email.
Single
1 access code
Full access for one singer. Works across all your devices with the same code and email.
Get AccessQuartet
4 access codes
One code per member. Train individually between rehearsals and build ensemble intonation skills together.
Get AccessEnsemble
12 access codes
For small ensembles and a cappella groups. Distribute codes to your members and track collective progress.
Get AccessChorus
40 access codes
For full choruses and large vocal ensembles. Give every section access to systematic ear training.
Get AccessCommon Questions
What is just intonation and why does it matter for singers?
Just intonation is a tuning system based on pure harmonic ratios — the natural relationships between frequencies. When singers tune to these pure ratios rather than piano tuning (equal temperament), chords ring with clarity and resonance. It's the difference between a chord that sounds good and one that locks in with a physical buzz you can feel.
Do I need special equipment?
Just a device with a microphone and a modern web browser. Intonation Lab works on desktop, tablet, and phone. No downloads or installation needed. A USB microphone or headset can improve accuracy, but built-in microphones work fine for most users.
What's the difference between the license tiers?
Single ($99) gives one person access. Quartet ($299) includes 4 access codes — one per member. Ensemble ($499) includes 12 codes for small groups. Chorus ($999) includes 40 codes for large ensembles. All access codes are delivered instantly by email after purchase.
Can I use it on my phone?
Yes. Intonation Lab runs in any modern browser on desktop, tablet, or phone. The responsive layout adapts automatically. Your settings and training progress are saved in your browser.
Is Intonation Lab only for advanced singers?
Intonation Lab is designed for all levels. Beginners can start in Basic mode with a generous accuracy window of ±25 cents. The guided curriculum progresses gradually from easy intervals to harder ones. Advanced and expert sensitivity levels challenge even professional singers.
How is this different from a regular tuner?
Standard tuners tell you if a single note is sharp or flat relative to equal temperament. Intonation Lab understands musical context — it knows what interval or chord tone you're aiming for, calculates the exact just intonation target, and shows you through multiple visualizations how close you are. It trains your ear, not just your eyes.
Ready to train your ear?
Intonation Lab gives you the tools to hear, see, and develop the precise pitch skills that make voices and ensembles ring. Pair it with private coaching for even faster results.
Get AccessQuestions? Email ted@tedsvoiceacademy.com · Browse all products