Episode 3: The Unison — Two Strings, One Sound

88 Lessons: Learn to Tune a Piano by Ear in 90 Days Hosted by Eathan Janney, PhD — Piano Technician & Neuroscientist

“A unison is not two strings sounding like one. It is two strings becoming one. That moment — when the beating finally stops and the sound locks into stillness — is the first thing you will ever truly tune. Everything in this craft begins here.” — Eathan Janney

Listen to Episode 3

Episode 3 is now available on all major podcast platforms. Search “88 Lessons” on Spotify, Apple Podcasts, or wherever you listen — or subscribe at 88-lessons.bywillo.ai/podcast to get every new episode delivered automatically.

Episode Overview

Runtime: ~15 minutes Series: 88 Lessons — Lesson 3 of 88 Topic: Piano Tuning Unisons — Two Strings, One Sound Target listener: Beginners who have completed Episodes 1 and 2 (or anyone who wants to understand what a piano tuning unison is and why it’s the foundation of all aural tuning)

Episodes 1 and 2 built the perceptual foundation: you understand what beats are, you’ve held a tuning fork, you’ve done your first live beat-detection drill. Now, in Episode 3, the real tuning work begins. Most piano notes are produced not by a single string but by two or three strings vibrating together — and they must all vibrate at exactly the same frequency. When they don’t, they beat. When they do, they lock into a single, still sound. Tuning a unison is the first genuine act of piano tuning, and this episode is where you experience it for the first time.

Timestamps

0:00 — Recap of Episodes 1 and 2: beats, stillness, and the tuning fork
1:30 — What is a unison? How most piano notes are constructed
3:00 — Why unison beats sound different from other beating intervals
5:15 — The experience of “locking” — what it feels like when a unison becomes still
7:00 — The three-string challenge: why the middle string is always last
9:30 — Your first unison listening drill (with or without a piano)
11:45 — Why unisons are the foundation of everything that follows
13:30 — What’s coming in Episode 4 and this week’s daily practice

Full Episode Summary

Why Every Piano Note Is a Chord You Can’t See

Most people think of a piano note as a single string vibrating when a key is struck. The reality is more complex — and more beautiful. In the middle and upper register of nearly every piano, each key triggers not one but two or three strings simultaneously. These strings, called unison strings, are designed to vibrate at exactly the same frequency, blending into a single, unified tone that is richer and more resonant than any single string could produce alone.

The word unison means “one sound.” When the strings are perfectly in agreement, that description is literally accurate: two or three separate strings become acoustically indistinguishable, fusing into a single voice. That fusion is the goal of unison tuning — and it is the first real precision goal an aural tuner learns to achieve.

The critical phrase here is “exactly the same frequency.” Not approximately. Not close enough. Exactly. Because even a tiny deviation — a fraction of a Hz — produces audible beating that any listener will perceive as instability or muddiness in the note. The piano technician’s ear is trained to detect and eliminate that deviation, consistently, across every note on the keyboard.

What Unison Beats Sound Like — and Why They’re Unmistakable

When two strings are slightly out of tune with each other, their sound waves interact in a way that produces a rhythmic pulsing — a “wah-wah-wah” — that varies in speed depending on how far apart the pitches are. You were introduced to this phenomenon as the concept of beats in Episode 1. Now, in Episode 3, you hear it applied to the most important context in piano tuning: the unison.

Unison beats have a distinctive character. Because the two strings are supposed to be at the same pitch — not a fifth apart, not an octave apart, not a third — the beating feels wrong in a particular way. It has an urgency to it, a restlessness, that even untrained listeners can sense as “something off” with the note. In aural tuning, learning to hear this restlessness clearly — and to track it as you adjust the tuning pin — is the skill at the center of Episode 3.

Eathan walks through the perceptual experience in detail: what a slowly beating unison sounds like at 1 beat per second, what a fast unison sounds like at 5 beats per second, and — most importantly — what zero beats sounds like. Silence. Lock. Stillness.

The Moment the Sound Locks

There is a moment in every unison adjustment that experienced piano technicians describe the same way: the sound “locks.” The beating, which was present and measurable, suddenly disappears. The two strings cease to fight each other and merge into a single, sustained tone that seems to expand and settle into the room.

This is not a subtle phenomenon. Once you’ve heard it, you know it instantly. It is one of the most satisfying sounds in all of acoustic craft — the moment a physical system reaches equilibrium, expressed entirely in sound.

Episode 3 is designed to give you this experience, or to begin developing the sensitivity to recognize it. Eathan guides you through the perceptual landmarks: what “almost locked” sounds like, what “just past locked” sounds like (because you can overshoot in either direction), and how to find the center with increasing reliability.

The Three-String Problem

In most of the piano’s middle and upper range, notes have three strings — not two. This creates a specific technical and perceptual challenge: you cannot tune all three simultaneously. Standard technique requires muting one string at a time, tuning the others in pairs, and then bringing in the final string last. The order matters, and Episode 3 explains why the middle string is almost always the last one set.

Understanding this process also reveals something deeper about aural tuning: it is always a sequential, iterative process. You are not placing all the pieces at once. You are listening, adjusting, listening again, adjusting again — each iteration refining the previous one — until the system reaches the quiet equilibrium you’re after.

Key Concepts from This Episode

Concept	Plain-Language Definition
Unison	Two or more strings tuned to exactly the same pitch — each piano note in the middle/upper range has 2 or 3
Unison beats	The rhythmic pulsing produced when unison strings are slightly out of tune with each other
Beat rate	The speed of the pulsing, measured in beats per second — a unison’s target beat rate is zero
Locking	The moment unison beats disappear and the strings fuse into a single, still tone
Muting	Temporarily silencing one or two strings with felt or a rubber mute so you can hear individual strings clearly
Inharmonicity	The subtle way real strings deviate from ideal physics — affects how precisely a unison can be set

What You’ll Practice: The Unison Beat-Tracking Drill

This week’s ear training exercise develops your ability to follow beats as they change — the core perceptual skill of unison tuning.

What you’re training: Tracking a beating sound as it slows, stops, and locks — and learning to recognize the moment of stillness without overshooting it.

What you need: A piano (upright or grand) and ideally an A440 tuning fork. If you don’t have access to a piano, you can do a modified version with two simultaneous audio tones from a free tone generator app, adjusting one slightly while the other holds steady.

How to do it:

Strike A4 on the piano (the A above middle C — the same string you used in Episode 2). Listen to the full sound of the note. Notice whether it feels perfectly still or slightly wavery.
If you have a tuning fork, strike A440 and hold it near the string while the note sustains. Listen to the combined sound. Do you hear any beating between the fork and the string?
Now strike the A4 key and let the note ring for its full sustain. Do not adjust anything. Simply listen, and try to hear whether one string is subtly fighting another. In a slightly out-of-tune piano, you may hear a slow beat — a gentle wavering that was invisible to you before this course and may now be beginning to emerge as a separate thing you can track.
Alternate between listening with focused attention (trying to isolate the beat) and listening with relaxed attention (taking in the whole sound). Notice how your perception shifts between the two modes.
Practice for 2 minutes per day. You are training the auditory attention that makes unison tuning possible.

Why this works: Unison tuning is entirely a perceptual skill — the lever work is simple once the ear is developed. The ear develops through exactly this: structured, repeated listening, with gradually increasing sensitivity to small differences in a sound you are actively pursuing.

Premium Track: What’s in the Extended Episode

In the Episode 3 premium track, Eathan goes deep on unison technique and provides the hands-on tools that free listeners will develop more gradually:

Full muting technique walkthrough — exactly how to use rubber and felt mutes to isolate individual strings, with audio demonstrations of each step
Downloadable worksheet: “Your First Unison Tuning Observation Log” — a structured form to record what you hear as you work through your first unison adjustments
Extended audio drill: 20 minutes of guided unison beat-tracking practice — starting from a very fast beat and slowing gradually to zero, with Eathan narrating what you should be hearing at each stage
The three-string method, in full detail — with specific instructions for sequence, muting order, and how to check your work
Q&A from Eathan: “What should I do if the beating never seems to go away completely?”

Premium membership unlocks all 88 extended episodes, downloadable exercises, ear training audio drills, quizzes, and access to the 88 Lessons community.

What’s Coming in Episode 4

Episode 4: Equal Temperament — The Map Your Ear Is Building

With unisons established as your first precision target, Episode 4 steps back to reveal the larger system you’re building toward. Equal temperament is the tuning framework that governs every modern piano — the 12-note system in which specific intervals beat at specific, predictable rates. Lesson 4 explains what equal temperament is, why it was adopted, and how it becomes the “map” your ear will learn to navigate across the full 88 keys.

Subscribe now so Episode 4 arrives automatically when it’s released.

Continue Your Learning

Start from the beginning:

Episode 1: What Is Aural Piano Tuning? — The foundational episode: what aural tuning is, what beats are, and why this skill is learnable
Episode 2: The Tuning Fork — Your Only Reference — How to use an A440 tuning fork and your first real beat-detection drill

Related reading on this site:

How to Tune a Piano Unison: The Skill Every Tuner Learns First — A complete guide to piano tuning unisons for beginners
Can You Learn to Tune a Piano by Ear? The Honest Answer — Everything to know before committing to aural tuning
How to Tune a Piano by Ear: A Step-by-Step Guide for Beginners — The big-picture method, from first note to complete tuning

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Subscribe below to get Episode 4 the moment it drops — plus Eathan’s notes on what the first week of ear training should feel like as the beats begin to come into focus.

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The free podcast gives you the framework, the concepts, and a daily ear training exercise. The premium track is where deep skill development happens — the extended lessons, the hands-on drills, and the structured observation work that moves you from “I can hear beats” to “I can tune a piano.”

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Extended 30–45 minute deep-dive episodes for every lesson
Downloadable worksheets and structured observation logs
Narrated ear training audio drills with reference tones
Full episode transcripts and comprehension quizzes
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88 Lessons is hosted by Eathan Janney — PhD in Neuroscience, professional piano technician, and founder of Piano Technician Masterclasses. The series is designed to be the world’s most complete, progressive, and accessible introduction to aural piano tuning.

New episodes drop daily. Begin with Episode 1 and follow the progression — each lesson builds directly on the last.