How to Tune a Piano Unison: The Skill Every Tuner Learns First

If you want to learn how to tune a piano, there’s one skill you must master before everything else: tuning a unison.

Every piano note — except the lowest bass notes — is produced by two or three strings vibrating together. When those strings are not in tune with each other, they create a pulsing, wavering sound called beating. When they are perfectly in sync, the beating disappears and the strings merge into one pure, stable tone.

Learning to hear that difference, and to eliminate it, is the first real skill a piano tuner acquires. Everything else — equal temperament, pitch raises, octave tuning — comes after.

What Is a Piano Unison?

A unison is two or more strings tuned to the same pitch. In most of a piano’s range, each note has either two or three strings assigned to it. These are called unison strings, and they must vibrate at exactly the same frequency to sound clean and full.

Here’s the thing: even when a piano is “in tune” overall, individual unisons can be slightly off. One string might be a hair sharp or flat relative to its partners. When that happens, the note sounds wobbly — a telltale sign of a tuning that’s starting to slip.

Why Unisons Are the Ideal Starting Point

Unison tuning is the ideal introduction to tuning for several reasons:

1. The feedback is immediate. When you turn the tuning pin, you hear the beating change in real time. Speed up the beat, slow it down, eliminate it. The piano talks back to you.

2. The target is clear. Unlike interval tuning — where you’re trying to achieve a specific, acceptable level of beating — unison tuning has one goal: zero beats. Clean, still, stable.

3. It builds the ear-hand connection. The tuning hammer is a precise tool, but controlling it takes feel. Unisons let you develop that control before the task gets more complex.

Understanding Beating

Beating is a natural acoustic phenomenon. When two frequencies are close but not identical, they interfere with each other in a regular pattern. You hear this as a periodic fluctuation in loudness — the sound pulses or “wah-wah-wahs.”

The closer the two strings are to the same pitch, the slower the beating. When they reach exact unison, the beating completely stops.

Here’s how to think about it:

Fast beating = the strings are far apart in pitch
Slow beating = the strings are close but not quite there
No beating = perfect unison

The tuner’s job is to listen carefully enough to hear that progression and stop precisely at zero.

How to Practice Hearing Unisons

You don’t need a tuning hammer to start training your ears. Here are practical exercises:

Exercise 1: The Detuned Note Drill

If you have access to a piano and a tuning hammer (or even a professional-grade tuning fork setup), deliberately detune one string of a three-string unison. Now play the note slowly and listen.

Can you hear the beating? Try to count the beats per second. Now bring the string back toward pitch and notice how the beating slows. The moment it vanishes, you’ve found the unison.

Exercise 2: Muting for Isolation

Piano tuners use felt muting strips and rubber mutes to isolate individual strings. By muting all but two strings, you can hear the unison relationship between just those two.

This is standard technique. Learn to mute effectively and you gain precise control over what you’re listening to.

Exercise 3: Singing Along

Some ear training students find it helpful to hum or sing the pitch of one string while listening to the other. Your voice acts as a reference tone, and you can feel the physical sensation of beating in your throat when frequencies are close.

Common Mistakes When Learning Unisons

Listening for tone quality instead of beating. A fresh student often tries to make the note “sound good” rather than eliminating beating. Unison tuning is about precision, not preference. Develop the discipline to listen specifically for beating.

Moving the hammer too fast. A hair’s worth of movement on a tuning pin can change pitch dramatically. Slow down. Learn to control the hammer with tiny, deliberate turns.

Not settling the pin. A string might sound clean right after you adjust it, but then drift because the pin hasn’t been properly seated. Professional tuners learn a technique called pin setting — applying torque to stabilize the pin in its hole — to prevent this.

Tuning one string against the wrong reference. In a three-string note, you tune the middle string against the outer one that you’ve already verified. Then you tune the remaining string against the established pair. Sequence matters.

The Muting Sequence for Three-String Notes

Here’s the standard approach a professional tuner uses for a three-string note:

Mute strings 2 and 3. Tune string 1 to pitch using your reference (tuning fork or temperament octave).
Move mute to string 3. Now string 1 and string 2 are sounding. Tune string 2 to match string 1 — listen for beating between them, eliminate it.
Remove mute entirely. All three strings sounding. Now tune string 3 to match the pair — listen, eliminate beating.

Some tuners do this in a slightly different order based on preference and piano layout, but the principle is the same: tune each string against a known reference, one at a time.

Two-String Notes: The Bass Section

In the lowest bass register, piano notes often have only one string each. But in the mid-bass, you’ll find two-string notes (called bichords). These are tuned the same way as three-string notes, just simpler: mute one, tune the other, then release and check.

Unisons vs. Intervals: The Key Distinction

Once you can reliably tune unisons, you’ll start working on intervals — the relationships between different notes (octaves, fifths, thirds, etc.). This is where equal temperament tuning comes in, and where the complexity increases significantly.

But here’s the important thing: interval tuning still depends on unison accuracy. If a single string within a unison is slightly off, your interval checks will be compromised. Clean unisons are the foundation everything else sits on.

How 88 Lessons Teaches Unison Tuning

In our daily podcast series, we build toward unison tuning systematically. Before you ever touch a tuning hammer, we spend time developing your hearing — learning to detect beating, distinguishing fast and slow beats, developing the patience to listen carefully.

Then, when we introduce the actual technique, your ears are already ready.

We believe that most beginner tuners struggle not because they lack technical knowledge, but because their ears haven’t been trained yet. We fix that first.

Your First Real Goal as a Tuning Student

By the time you’ve completed the early lessons in 88 Lessons, you should be able to:

Detect beating between two strings
Describe it (fast, slow, none)
Use a tuning hammer to eliminate it
Settle the pin so the unison holds

That’s a concrete, achievable goal. And it’s the gateway to everything else.

Ready to Start?

88 Lessons is a free daily podcast teaching complete beginners how to tune a piano by ear in 90 days. New episodes release every day — start at Lesson 1 and follow along, one lesson at a time.

Your ears are more capable than you know. Let’s find out what they can do.