For many players, the piano’s keys and strings are the instrument.  You press a key, and the piano makes a sound.  If that sound isn’t right, you call the tuner to adjust the strings.

As you know, there’s actually a lot more going on in there… but the strings are certainly central.

Look inside almost any piano, and you will see at least two kinds of strings in three configurations.

Strings can be “wound” or “plain”.  A plain string is just that:  a length of steel wire.  And a wound string is a plain steel string with at least one layer of other string wrapped around it.  Usually, the wrapping string is mostly copper.

Why wrap strings?  Because vibration speed determines pitch.  So the faster a string vibrates, the higher the pitch it produces.  And vice versa.

To create a low bass sound, a string must vibrate slowly.  And vibration speed is controlled by length, stiffness, and mass.  Where’s the longest part of your grand piano?  In the bass!  And why are pianos “cross-strung”?  So the strings can be longer than the piano is tall or long.

But to get a bass vibration speed from a plain steel string, it might have to be thirty feet long….  Therefore, string makers add stiffness and mass with windings, so a shorter string will vibrate at the proper speed.

Those heavier strings make more sound, however, so lighter strings are strung in pairs or triples to help equalize the volume from one end of the piano to the other.

In the low bass, each hammer hits one heavily wrapped string (sometimes wrapped in two layers).  Higher up, the more lightly-wrapped strings are in pairs.  Finally, from the middle up, each hammer hits a trio of plain strings.

Steel strings will rust in humid conditions, and copper windings can develop verdigris (which isn’t necessarily a problem but can indicate that one exists).  Ask your technician about the condition of your piano’s strings.