Tangent

What it means

The tangent is a small metal plate at the rear end of the clavichord key. When the player presses the key, the tangent strikes the string from below and remains resting there. It thus fulfils two tasks at once: it excites the string and at the same time limits its vibrating portion, thus determining the pitch. Only when the key is released does it fall back, and a strip of felt damps the string. From this construction follows the peculiarity of the clavichord: the contact between finger and string remains in place while it sounds.

Musical use

No other keyboard instrument allows such a direct connection to the note. Because the tangent lies on the string, a change of pressure by the finger changes the string tension and thereby the pitch: this is how Bebung arises, a vibrato possible only on this instrument. The force of attack determines the volume, though within a very quiet range — the clavichord is an instrument for the small room and for practising, not for the hall. In the seventeenth and eighteenth centuries it was widespread and valued for its expressive possibilities.

Performance practice

Play from the fingertip with a controlled, not too fast attack; a hard stroke drives the pitch upward and sounds impure. Keep the weight constant after the attack, for every fluctuation is audible as a change of pitch. The Bebung arises from a very small, even yielding of the finger and is used sparingly. Watch for absolute silence in the room, because the instrument is quiet. Tune yourself regularly and check the height of the tangents, since even small deviations change the response.

Bear in mind that many clavichords are fretted: several keys then act on the same string, so that certain pairs of notes cannot sound at the same time. Check this before choosing a work, because some movements cannot be executed on such an instrument. The room must be very quiet, and even quiet extraneous noises cover the instrument.