Unlike Piano, Harpsichord’s Pluck the Strings with the Quills of Bird Feathers. The volume of a Harpsichord does not change, hitting the keys harder or softer has no effect on the volume of the note.
Both Clavichords and Harpsichords were generally too quiet to be used for performance. Trumpets and Violins were much louder. They also lacked touch sensitivity, hitting the key harder or softer had little or no effect on the volume of the note.
Despite their lack of volume a popular German Composer, Johann Sebastian Bach, wrote Concertos for Harpsichord in the early 1700’s