Since the string vibrates from the bridge only as far as the tangent, multiple keys with multiple tangents can be assigned to the same string.
This is called fretting.
Early clavichords frequently had many notes played on each string, even going so far as the keyed monochord—an instrument with only one string—though most clavichords were triple- or double-fretted.
Since only one note can be played at a time on each string, the fretting pattern is generally chosen so that notes rarely heard together (such as C and C♯) share a string pair.
The advantages of this system compared with unfretted instruments (see below) include relative ease of tuning (with around half as many strings to keep in tune), greater volume (though still not really enough for use in chamber music), and a clearer, more direct sound.
Among the disadvantages: temperament could not be re-set without bending the tangents; and playing required a further refinement of touch, since notes sharing a single string played in quick succession had to be slightly separated to avoid a disagreeable deadening of the sound, potentially disturbing a legato line.

Some clavichords have been built with a single pair of strings for each note.
The first known reference to one was by Johann Speth in 1693 and the earliest such extant signed and dated clavichord was built in 1716 by Johann Michael Heinitz.
Such instruments are referred to as unfretted whereas instruments using the same strings for several notes are called fretted.
Among the advantages to unfretted instruments are flexibility in tuning (the temperament can be easily altered) and the ability to play any music exactly as written without concern for "bad" notes.
Disadvantages include a smaller volume, even though many or most unfretted instruments tend to be significantly larger than fretted instruments; and many more strings to keep in tune.
Unfretted instruments tend to have a sweeter, less incisive tone due to the greater load on the bridge resulting from the greater number of strings, though the large, late (early 19th century) Swedish clavichords tend to be the loudest of any of the historic clavichords.
Since the string vibrates from the bridge only as far as the tangent, multiple keys with multiple tangents can be assigned to the same string. This is called fretting. Early clavichords frequently had many notes played on each string, even going so far as the keyed monochord—an instrument with only one string—though most clavichords were triple- or double-fretted. Since only one note can be played at a time on each string, the fretting pattern is generally chosen so that notes rarely heard together (such as C and C♯) share a string pair. The advantages of this system compared with unfretted instruments (see below) include relative ease of tuning (with around half as many strings to keep in tune), greater volume (though still not really enough for use in chamber music), and a clearer, more direct sound. Among the disadvantages: temperament could not be re-set without bending the tangents; and playing required a further refinement of touch, since notes sharing a single string played in quick succession had to be slightly separated to avoid a disagreeable deadening of the sound, potentially disturbing a legato line.
Some clavichords have been built with a single pair of strings for each note. The first known reference to one was by Johann Speth in 1693 and the earliest such extant signed and dated clavichord was built in 1716 by Johann Michael Heinitz. Such instruments are referred to as unfretted whereas instruments using the same strings for several notes are called fretted. Among the advantages to unfretted instruments are flexibility in tuning (the temperament can be easily altered) and the ability to play any music exactly as written without concern for "bad" notes. Disadvantages include a smaller volume, even though many or most unfretted instruments tend to be significantly larger than fretted instruments; and many more strings to keep in tune. Unfretted instruments tend to have a sweeter, less incisive tone due to the greater load on the bridge resulting from the greater number of strings, though the large, late (early 19th century) Swedish clavichords tend to be the loudest of any of the historic clavichords.
Clavichord