Clavichord

What it means

On a clavichord, a small upright brass blade called a tangent is fixed to the back of each key. Pressing the key drives the tangent up against the string, slightly raising its pitch and remaining in contact with it for as long as the note sounds; the tangent also fixes the vibrating length of the string and therefore the pitch.

Because the tangent stays in contact with the string, the player can still shape the tone after the initial attack by varying finger pressure, producing a gentle wavering called Bebung. No other historical keyboard instrument allows this kind of after-touch.

Musical use

From the late Middle Ages into the 18th century, the clavichord served mainly as a practice and household instrument, valued for its intimate, touch-sensitive response but too quiet for large rooms. Carl Philipp Emanuel Bach, in his Essay on the True Art of Playing Keyboard Instruments (1753/62), described it as the instrument on which expression and fingering could be learned most precisely.

The clavichord should be distinguished from the harpsichord: on a harpsichord the strings are plucked by a quill, so volume stays essentially constant regardless of touch, whereas the clavichord, like the later fortepiano, responds to how hard a key is struck, though it always remains very quiet and cannot produce a sudden accent. It is therefore often seen as a tonal forerunner of the hammer-action piano, even though the two mechanisms work quite differently.

Performance practice

When you play a clavichord, keep your touch even and calm: because the tangent keeps shaping the tone after the key is depressed, any unsteadiness in the hand becomes audible in the sound. Practice Bebung by letting a held note waver gently through light, rhythmic finger pressure without fully releasing the key.