How a Piano Is Tuned: String by String
How do you tune a piano with about 230 strings, each one pulled tight with great force? Tuning is precision work, string after string, until every note sits in its place and every chord sounds whole.
In this guide we'll explain what happens inside the piano during a tuning, why the sound drifts over time, and what else a visit includes besides the strings.
Strings and pins
Open the lid of an upright piano and you'll see long rows of shiny strings. In the middle of the keyboard and in the treble, each key sets off three strings, and in the low notes, where the strings are thick and heavy, two strings or a single one. Each string is wound around a metal pin set deep into a wooden block, and when the pin is turned, the string's tension changes and the pitch goes up or down. The tool that turns the pins is called a tuning lever. The pins sit tightly in the wooden block, and that is how they hold the tension the string was given during tuning. You can follow the path from the key to the string up close in How a Piano Works.
The starting point
A tuning is built around one note from which all the others are derived, usually the A above middle C, at 440 Hz. From there one octave is tuned in the middle of the keyboard, and then the tuning is spread octave by octave, upward and downward, checking each note against the ones already tuned. That way each new note rests on a foundation that is already in place, and the whole keyboard is built around the same center.
The 440 Hz standard was adopted in the early 20th century, after a long period in which every place tuned to its own pitch. Since then it has been the most common reference in the world, which is how a piano, a violin and a flute can play together at the same pitch.
Harmony between the strings
When two strings of the same note are tuned slightly differently, a beat forms between them, a small wave that rises and falls in the sound. During tuning, the neighboring strings are briefly muted with mutes, one string is tuned, and then the other strings of that note are brought to it until the beat disappears and they sound as one voice.
There is also harmony between the notes themselves. Pianos use a system called equal temperament, in which every interval is adjusted slightly so that all keys sound good. In the upper range the octaves are stretched a little to match the strings' overtones, so the sound stays bright and balanced along the whole keyboard.
More than tuning: the action and the hammers
Under the keys, the action is at work, and it too is regulated at regular intervals. Regulating the action adjusts the distances and movement of its parts, so every key answers the fingers with the same feel. There is also care for the hammers: their felt becomes more compressed over the years, and adjusting it brings back the tone of the sound.
Why the sound drifts
The strings rest on the soundboard, a thin wooden panel with a gentle arch. In humid air the wood absorbs moisture, the crown grows and the pitch climbs slightly. In dry air the opposite happens, and the pitch drops. In a new piano the strings themselves also stretch gradually over the first months, which is why a new piano benefits from a few tunings in its first year. Steady humidity of 45%-50% helps the tuning hold, and there's more on that in Maintenance and Humidity. In most homes, tuning once a year is enough.
Tuning at your home
Zohar Pianos tuners come to your home, anywhere in the country, and each visit takes two to three and a half hours, depending on the piano. Our tuners are the most professional, experienced and skilled in the country, at the most fair and affordable prices, so you can be completely at ease. After a move, the piano gets one to two weeks to settle in, and then it is tuned. All our piano moves are fully insured from start to finish with the most comprehensive coverage, at no extra cost. What the move itself looks like: How to Move a Piano, and what the quote includes: How Much Does Piano Tuning Cost · How Much Does Piano Moving Cost.
If you bought your piano from Zohar Pianos, you can join Zohar Pianos Plus, a yearly membership with reminders from us throughout the year, designed for pianos bought from Zohar Pianos. And what else the person who comes to you does, in What Does a Piano Tuner Do. Whatever your question about your piano, we're here for you.
Links: Book a Piano Tuning · Piano Tuning · How Much Does Piano Tuning Cost · What Does a Piano Tuner Do · How to Move a Piano · How Much Does Piano Moving Cost
Frequently asked questions
How long does a piano tuning take?
A tuning visit takes two to three and a half hours, depending on the piano.
How often should a piano be tuned?
In most homes, tuning once a year is enough.
Why does a piano go out of tune even when no one plays it?
The soundboard wood reacts to the seasons. As it swells or shrinks, the tension on the strings changes slightly, and the pitch rises or falls with it.
What is action regulation?
Adjusting the distances and movement of the action's parts, so every key answers the fingers with the same feel.
Do you tune at home?
Yes. Our tuners come to your home, from the north to the south. After a move, the piano is tuned one to two weeks after it arrives.