From early keyboards to the modern piano

The piano is only three centuries old. Before it, and long alongside it, other keyboard instruments shaped the music we play today. Knowing them explains a lot: why Bach writes almost no dynamics, why Mozart calls for such a light touch, why Liszt can make the instrument thunder.

The organ

The oldest keyboard (the hydraulis of ancient Greece is its ancestor). Sound comes from pipes fed with air: it lasts as long as the key is held, without fading, but the organist can't shade it by touch. Colour is changed by pulling stops (registers).

The clavichord

An intimate instrument: a small metal blade (the tangent) strikes the string and stays pressed against it. The sound is very soft but touch-sensitive: you can shade it and even add a slight vibrato (the Bebung). It was a favourite practice instrument of Bach and his son Carl Philipp Emanuel.

The harpsichord

Here the string is plucked by a small plectrum (quill, nowadays plastic). The sound is bright and rich, but how hard you press barely changes the volume. Harpsichordists shape the music differently: through articulation, timing, ornamentation, registration and switching between manuals (on two-manual instruments). Couperin, Rameau, Scarlatti, Bach and Handel wrote for it.

The fortepiano

Around 1700 in Florence, Bartolomeo Cristofori invented a “harpsichord that plays soft and loud” (gravicembalo col piano e forte): hammers strike the strings and immediately rebound. For the first time, finger force directly controls volume. The fortepiano of Mozart and the young Beethoven is light, with a nimble Viennese action and a clear sound that decays quickly; its range is about five octaves.

The modern piano

In the 19th century the instrument transformed to fill ever larger concert halls:

• 1821: Sébastien Érard patents the double escapement, allowing very fast repetition of the same note;
• a one-piece cast-iron frame (1850s–60s), higher string tension, a more powerful and sustained sound;
• the range extended to 88 keys (just over 7 octaves);
• three pedals: sustain (damper), una corda (soft pedal) and later the sostenuto, which sustains only notes already held.

Chopin, Liszt, Brahms, then Debussy and Ravel wrote for this new instrument, able both to sing and to thunder.