In the late 1750s a number of German piano builders emigrated to Britain, and one, Johann Christoph Zumpe, invented an extremely simple action for the square pianos he began building in the mid-1760s. Zumpe’s action goes back to the Cristofori-Silbermann system in which the hammers point away from the player and are hinged to a rail over the keys. A metal rod tipped with a padded button is driven into the back of the key. When the key is depressed, the rod pushes the hammer upward; the key is stopped by a padded rail over its back end, and the hammer then flies freely. Despite the lack of an escapement, Zumpe’s square pianos were an enormous commercial success and were copied in France, the Low Countries, and Scandinavia.

Zumpe had worked for the harpsichord builder Burkat Shudi when he first came to England, and around 1770 three other workmen in Shudi’s shop, John Broadwood, Robert Stodart, and Americus Backers, devised for grand pianos an adaptation of Zumpe’s action that included an escapement. This important development made London a major centre of piano building and created a characteristic English piano of fuller and louder sound than the Viennese piano but with a heavier, deeper touch and a consequent inability to play repeated notes as rapidly. In the English grand-piano action, the fixed rod of Zumpe’s square-piano action was replaced by a pivoted jack, similar to that in Cristofori’s action. The upper end of the jack fits into a notch at the base of the hammer shank, slipping out of the notch as the back of the key reaches its highest point; the hammer then flies free, strikes the string, and falls back to be caught by a hammer check even when the front of the key is still held down. The tone of a typical 18th-century English grand piano is surprisingly reminiscent of the tone of an English harpsichord, suggesting that the English piano makers were, like Cristofori, seeking to make an expressive harpsichord, unlike the German builders who, in effect, appear to have been trying to build a louder clavichord.

Unlike their Austrian and German counterparts, English pianos had two or, at most, three pedals. One of the two ordinary pedals shifted the keyboard sideways so that the hammers struck two or only one of the three strings provided for each note. The second pedal raised all the dampers. It was sometimes replaced by two pedals—one for the treble dampers, the other for the bass dampers—or, occasionally, by a single damper pedal divided into two parts that could be depressed separately or together with one foot, as on the piano presented by Broadwood to Beethoven in 1817.

Although the pianos of the late 18th and early 19th centuries were perfected instruments ideally suited to the music of their period, the increasing popularity of public concerts in large halls and concerti with large orchestras stimulated attempts by piano builders to produce an instrument of greater brilliance and loudness. Their efforts gradually created today’s vastly different piano. In recent years, the special merits of the earlier instruments (sometimes called “fortepianos” to distinguish them from modern pianos) have come to be appreciated, and several builders have begun to make replicas of them.

Other early forms

As previously mentioned, many 18th-century pianos were “squares,” built in a form resembling the clavichord. More compact and less expensive than wing-shaped grands, the square piano continued through much of the 19th century to be the most common form of piano in the home. But as square pianos became larger and larger, these advantages diminished, and the square piano was eventually replaced by the upright. In the 18th and early 19th centuries, upright pianos (i.e., pianos with vertical strings and soundboard) took three different forms. In the “pyramid piano” the strings slanted upward from left to right, and the case above the keyboard took the form of a tall isosceles triangle. Or a grand piano was essentially set on end with its pointed tail in the air, producing the asymmetrical “giraffe piano.” Placing shelves in the upper part of the case to the right of the strings yielded the tall rectangular “cabinet piano.” Because the lower end of the strings, which ran nearly vertically, was about at the level of the keyboard, all such instruments were very tall. Although there were attempts to construct lower instruments by, in effect, positioning a square piano on its side, the American builder John Isaac Hawkins made the first truly successful low uprights in 1800 by placing the lower end of the strings near floor level. Robert Wornum in England built similar small uprights in 1811, and in 1842 he devised for them his “tape check” action, the direct forerunner of the modern upright action.

Bracing and frame

Like 18th-century harpsichords, the pianos of the 18th and early 19th centuries were constructed entirely of wood, with the case (supported by a structure of internal wooden braces) sustaining the entire stress exerted by the strings. The only metal bracing in such instruments appears in the form of flat or arched pieces bridging the gap through which the hammers rise to strike the strings. These braces eventually proved insufficient when the walls of the case itself and the pinblock (the long piece of wood into which all the tuning pins were driven) were incapable of withstanding the increasing tensions placed upon them. For this reason, ever-increasing quantities of metal bracing came into use, first in the form of individual bars running parallel to the strings from the side of the case to the pinblock but finally in the form of a single massive casting that took the entire tension of the strings upon itself. The one-piece cast-iron frame was first applied to square pianos by Alpheus Babcock of Boston in 1825, and in 1843 another Bostonian, Jonas Chickering, patented a one-piece frame for grands. With the adoption of such frames, the tension exerted by each string (about 24 pounds [11 kilograms] for an English piano of 1800) rose to an average of approximately 170 pounds (77 kilograms) in modern instruments, the frame bearing a total tension of 18 tons.