The Evolution Of The Piano Action

As you can see in our last entry, Cristofori’s early "pianoforte" looked more like a haprsichord, with no inner metal frame, only two strings per unison, and only a 4 octave range. But it was definitely a beginning for the first keyboard instrument to strike the strings with a hammer instead of plucked with a quill (harpsichord) or struck with tiny tangents (clavichord.) Cristofori used deer leather to fashion his original hammers.

By the 1720’s Cristofori had made some twenty "gravicembali col piano e forte" ("harpsichord with soft & loud") and had added a padded "backcheck" to catch the hammer on the rebound. A sketch of Cristofori’s early piano action is shown below

 This original design was little changed over the next fifty years, as keyboard players of the day just began to explore the potential of this new "soft-loud" instrument. One of the key limitations (no pun intended) in Cristofori’s early design was the necessity to allow each key to raise all the way back up, before being able to play the key & hammer again for another strike of the note. You had to lift fully off the key because that’s what it took to bring all components back to their ready-to-play positions. This made it impossible to repeat notes quickly, and as new composers for this wonderful instrument entered the field, they demanded faster repetition for their more allegro, presto and vivace compositions. Cristofori began work on the early versions of an extra stick of wood, a "repetition lever," that would hold the hammer aloft only half-way back to rest position, allowing it to  be replayed without allowing the key to raise fully back up.

This repetition action was improved further by the great Parisian piano maker Sebastian Erard, who invented a "double escapement" around 1821 (Erard pianos are still made today!) Indeed, this ability to repeat any note more and more rapidly, with less and less raise of the key, became one of the most dominant quests in piano evolution, as great composers of the baroque, classical and romantic eras wrote more quick & lively passages and trills into their increasingly ornamental pieces. And although many would surmise that we have come as far as we can, and achieved maximum key-repeat velocity in the modern era of piano design, a visit to the Steinway factory in New York (a field trip I highly recommend!) will reveal that their action technicians still work on ways to improve this even further, introducing new experimental action designs every few years.

But increasing the rapid repetition of keys and notes proved to be only one of many problems that would rear their head in the evolution of the modern piano.  A discussion of these issues, and one man who made huge improvements in these areas, John Broadwood, follows next

For more check out these related posts

• The Modern Piano Emerges
• John Broadwood Battles Increasing Tension!
• The Piano: An Amazing Feat Of Engineering
• Music And The Birth Of The Piano