What Is Piano Tuning? A Plain-English Explanation

Piano tuning is the adjustment of the tension of each of a piano's strings so that every note sounds at its correct pitch — and in correct relationship to every other note. A piano has about 230 strings for its 88 keys; each wraps around a tuning pin, and turning that pin a fraction of a degree raises or lowers the string's pitch. A technician works through all of them, by ear, until the instrument agrees with itself and with the international standard (A above middle C at 440 vibrations per second — "A440"). That's the whole idea. Here's the slightly longer version, including what tuning is not.

Why a piano needs it

Strings don't hold their pitch forever. The main reason isn't playing — it's humidity. A piano's soundboard is a large sheet of spruce under the strings; it swells when the air is damp and shrinks when it's dry, and every swell and shrink changes the tension on the strings above it. In a Canadian year, with humid summers and furnace-dry winters, that cycle pulls a piano out of tune on its own, whether or not anyone touches it. Playing adds a little; moving the piano adds more; new strings stretch for a year. How often this means tuning — for most home pianos, once a year.

What "out of tune" sounds like

Two things. Pitch drift — the whole piano has sagged below A440, so it sounds flat against a recording or another instrument (most people can't hear this alone; it's relative). And internal disagreement — notes no longer match each other: a single key sounds like two slightly different pitches (its two or three strings have separated — a "sour unison"), octaves don't ring cleanly, chords sound muddy. That second kind is what everyone hears, and it's the one that makes a piano unpleasant to play.

What a tuner actually does

Sits at the piano for about ninety minutes with a tuning lever and some felt mutes. Sets a reference octave in the middle of the keyboard (the "temperament"), then works outward string by string, listening to the interaction between notes and nudging pins until the beats disappear. Strikes keys firmly to make sure each pin has truly settled, because a pin left "visiting" slips within weeks. Plays music at the end to check the whole. The full visit, narrated.

A piano that's gone years untuned sags too far to correct in one pass and needs a pitch raise — a quick first pass to bring everything close, then a fine tuning on top. That's why a first visit on a neglected piano costs more and takes longer.

What tuning is not

Three other services get confused with it:

• Regulation adjusts the mechanism — the thousands of moving parts between key and hammer — so the touch is even and responsive. Tuning changes what you hear; regulation changes what you feel.
• Voicing adjusts the hammers — reshaping and softening or hardening the felt — to change the tone from harsh to warm or dull to clear. A piano can be perfectly in tune and still sound harsh; that's voicing.
• Repair fixes things that have broken or worn: strings, keys, pedals, felts.

A good tuner notices all of these during a tuning visit, handles the small ones on the spot, and tells you plainly about the larger ones.

What it costs and how long it lasts

In the GTA, a standard tuning runs roughly $150–$240 — ours is $160 ($140 at the current intro rate) — with a pitch raise priced higher for the first visit on a neglected piano (the full cost picture). In a stable room, a tuning holds six to twelve months; beside a radiator or in a swinging-humidity room, far less. The room decides more than the tuner does.

That's piano tuning: not mysterious, not quick, and the single most important thing a piano needs every year. Book one.

Common questions

What does it mean to tune a piano?
To adjust the tension of each string so every note sounds at its correct pitch and in tune with every other note — done by turning the tuning pins, by ear, across all ~230 strings.

Why do pianos go out of tune?
Mainly humidity: the wooden soundboard swells and shrinks with the seasons, changing string tension. Playing, moving, and new strings stretching add to it.

Is tuning the same as fixing a piano?
No. Tuning sets pitch. Regulation fixes touch, voicing fixes tone, and repair fixes broken or worn parts. A tuning visit usually includes small fixes, but they're different jobs.