composers like J.S. Bach and his sons, Haydn, Mozart and Beethoven admired the clavichord because of its sympathetic expressiveness. But it was distinctly a private or domestic instrument, lacking the sonority and ictus for public use. Late examples, however, sometimes had two strings to a note for greater power. Its manufacture ceased before the 19th century, though instruments lingered in use long after 1800.
The harpsichord was simply a keyboard zither or psaltery. For each key of the keyboard there was a corresponding string, past which depressing the key pushed a jack from whose side projected a small quill or spine by which the string was snapped or twanged. When the key was released, the quill, which was jointed, slipped back into its first position and a damper fell upon the string. The strings varied in length according to pitch. Hence the frame tended to be roughly triangular or wingshaped (whence the German name 'flugel'), resembling a modern grand piano. The smaller varieties, known as 'spinets' or 'virginals,' had the strings running from side to side, but in larger ones they stretched away from the keyboard. An upright form, the 'clavicytherium,' was also occasionally made. Large instruments, for the sake of varied qualities, often had two or more keyboards, each provided with a special form of jack and quill. The cases and covers were often highly ornate, and, when the instrument had legs, these, too, were often elaborate.
The harpsichord tone was vigorous and sonorous, especially in the larger varieties, with a peculiar reedy quality. It had a decided ictus from the snap of the quill past the string. But it could not be reduced in power below a certain point without 'blocking' (though variations in power were often secured by some sort of opening and closing shutter or lid, controlled by a foot-lever). Neither could its character be much varied. Until late in the 18th century the harpsichord was the standard instrument for the theatre and concert-room, and for all chamber combinations. For public use it was often made with two or three strings to the note. It was no longer made after 1800, though its use continued later.
The early history of both the clavichord and the harpsichord cannot be traced. It seems likely that both were known as early as the 14th century, but definite data begin with the 16th. Their manufacture was more or less associated with that of the organ till the 17th, when the famous Ruckers family of Antwerp raised harpsichord-making to the grade of a fine art. In the 18th century Paris and London were the leading headquarters of good makers. The excellence of the best instruments lay chiefly in the perfection of their soundboards and the delicacy and precision of the action.
The pianoforte (or 'fortepiano,' as at first called) is essentially a keyboard dulcimer. Each key has its own string, sounded by a blow from a recoiling hammer that has a padded head. Its invention was delayed until the making of clavichords and harpsichords was well advanced, since its success depended on mature experience in constructing frames, soundboards and key-action, as well as in the drawing of heavy wire. In the clavichord and harpsichord the strings needed to have some lightness
