Harpsichords are keyboard instruments that make sound by having the strings plucked with a plectrum. They are thought to have originated when a keyboard was attached to a psaltery. This makes them different from a clavichord where the strings are hit. The piano is therefore closer to a clavichord than a harpsichord. On a piano it is possible to play louder or quieter by playing the keys with more or less force. On a harpsichord the volume (playing louder or softer) cannot be controlled by the way it is played. However, some large harpsichords have several "stops", each one giving a different kind of sound. The largest harpsichords have two manuals (keyboards) which gives more variety. It makes it possible for the right hand to play the tune on one manual while the left hand plays an accompaniment more quietly on the other.