The Harpsichord

Generally longer and narrower than a piano, the harpsichord commonly has a shape similar to a grand piano. The metal strings are sounded by plucking with a small piece of material called a plectrum which is held in a narrow slip of wood called a jack attached to the key mechanism. A downward stroke on the key raises the plectrum on the other end so that it plucks the string and then pivots so that it does not touch the string on the way down. A drawback to the instrument is the fact that the player has no control over the loudness and quality of the tone, since that tone is produced by the single pluck. During the period of about 400 years when it was a major keyboard instrument, variations were made to partially overcome this limitation. Double sets of strings were used with separate jacks for each set. Mechanisms were used to move one set of jacks out of reach of the strings so that variations in volume and quality could be achieved. Some harpsichords had two keyboards with different sets of strings which could be coupled.

Ranks of Organ Pipes

A complete set of organ pipes of the same type is called a rank. In a large modern organ, the keyboard span is typically five octaves from C2 to C7. With 12 semitones per octave, this gives 61 pipes for a rank. Five doublings of length means that the longest pipe in a rank is 32 times the length of the shortest pipe.

Since the idea of a rank is to produce a set of pipes with similar tone quality, it has been found to be necessary to scale the diameters in a different way than the lengths. In order to enhance the higher harmonic content of the longer pipes, it has been found desirable to make their diameters smaller in proportion to their lengths. In a rank, the diameter of the longest pipe will be 12 to 13 times the diameter of the shortest pipe, while the length has increased by a factor of 32.