Why do pianos have three pedals, and what do they do?

3 December 2024, 13:56

Most pianos have three pedals, but what do they do? We take a look at what is actually going on.

Pianos can be found almost everywhere these days. From hotel lobbies to town halls, cocktail bars and even railway stations, you are never that far away from a piano. They are depicted being played in hit TV shows such as Bridgerton and Channel 4’s The Piano and are the most obvious symbol of music-making in all forms.

And whether an upright, grand or electric piano, they usually have one thing in common: three pedals, that the pianist will operate with their feet.

The development of piano pedals began from the very earliest days of the piano and continued through the late 19th century. Beethoven was a huge pioneer of the piano, writing increasingly experimental pieces that pushed the technical limits of the instrument.

Throughout the instrument’s evolution, there have been pianos with as many as six or more pedals! But over many years of development, and a little trial and error, piano makers have arrived at the present configuration of three pedals.

Read more: Why are piano keys black and white? And when did they change?

This piano doesn't have any black keys

Each pedal does a different and unique job, which changes the effect of the sounds produced. Modern pianos usually have three pedals, from left to right: the soft pedal (or una corda), the ’sostenuto‘ pedal, and the sustaining pedal (or damper pedal). Some pianos omit the sostenuto pedal or have a middle pedal with a different purpose such as a muting function, also known as silent piano.

Let’s dive into the detail...

1. What does the ‘Sustain’ pedal do?

   The sustain pedal is the most used of all the pedals. Located on the furthest right, it raises all the bits of felt material – or dampers – off the strings so that they keep vibrating, meaning the sound continues even after the player has released the key.

   The effect is a rich tonal quality, less percussive with more ring in the sound, which has been described as “the soul of the piano.” The sustain pedal also allows the player to connect notes in a far more smooth or legato way than could be achieved without it.

   

   Lang Lang — Chopin, “Raindrop” Prelude on the Steinway & Sons Spirio | r

2. What does the ‘Sostenuto’ pedal do?

   The last pedal added to the modern grand was the middle pedal, the sostenuto, which was pioneered by French piano builders Alexandre François Debain and Claude Montal in 1860 and 1862, respectively. These innovative efforts did not immediately catch on with other piano builders, as two pedals had become standard on most pianos at this time.

   It was Albert Steinway – whose name is now synonymous with one of the world’s leading piano brands – who perfected the sostenuto piano, advertising it publicly in 1876. This ultimately led to three pedals being the standard on all modern pianos.

   The sostenuto pedal makes it possible to sustain certain notes on the piano, without affecting any others.

   When the pianist holds down a note or chord and then depresses the pedal, the felt dampers on those notes will remain held up even after the keys are released.

   The result is that note or chord continues to ring until the pedal is released, while all other notes on the piano can be played normally. Have a look at the video below for a demonstration:

   

   Sostenuto Pedal Demonstration

3. What does the ‘Soft’ pedal do?

   The soft pedal, or una corda pedal, is the leftmost of the three pedals. It was invented by Bartolomeo Cristofori, an Italian instrument maker who is credited with the invention of the piano. The name “Una Corda” means “one string” in Italian and gives us a clue as to what the pedal does to the sound.

   The una corda primarily modifies the timbre, or tone quality, of the piano, not just the volume. When the una corda is activated, the entire action shifts to the right so that the hammers hit one string. The effect is a soft and otherworldly tone.

   Beethoven was one of the first composers to take advantage of this newfound effect, writing specifically in his ‘Hammerklavier’ Sonata for sections of the music to be played on one string.

   

   Beethoven - Sonata op. 106 "Hammerklavier" - III: Adagio sostenuto (score)

So there you have it! The three pedals of the piano are not just there to look pretty, but each adds a special extra colour to the music.