Harp - Structure and Mechanism

Structure and Mechanism

Harps are essentially triangular and are made primarily of wood. Modern harp strings are often nylon or, less often, metal; tuning pins are also metal components. The bottom ends of each string is fed through a small metal eyelet and tied in a knot on the inside of the sounding-board, which is the upward-facing surface of the resonating cavity (the sound box or body). The body is hollow and when a taut string is plucked, the body resonates, projecting sound both inward towards the harp player through a series of usually oval openings (whose principal purpose is to allow access to the strings and only secondarily to enhance resonance) and, much more importantly and powerfully, outward through the flexible and taut-strung sounding board. The crossbar, or neck, contains the mechanism or levers which determine the pitch alteration (sharps and flats) for each string. The upper ends of the strings are attached to pins in holes drilled through the neck at specific intervals and at specific distances from the soundboard.

The longest side of the harp is called the column or pillar. In those harps which have pedals, this side is a hollow column and encloses the rods which control the pedal mechanisms. At the base of a pedal harp are seven pedals, which activate the rods when the pedals are downwardly pressed. The modern sophisticated instrument spanning 6½ octaves in virtually all keys was perfected by the 19th-century French maker Sébastien Érard and because of its pedal-driven ability to play all sharps and flats of all notes within its range, it continues today as the standard style of most large professional concert harps.

Lever harps, however, do not have pedals or rods, and the pillar's only purpose in these instruments is to hold up the neck against the great strain of the strings. Lever harps use a shortening lever (usually shaped like a capital letter L) on the neck next to each individual string which is to be activated (i.e., turned) manually to shorten the string and raise the tone a half step. A string tuned to natural may be played in sharp, but not flat. A string tuned to flat may be played in natural, but not sharp. Also, in order to change a string from one tone to another during a performance, a harp player must take one entire hand off the harp for a moment and switch the lever—this may cause an acoustic gap in a performance, as for a brief moment only one hand will be in use. Lever harps are considerably lighter in weight than pedal harps and are smaller in size and number of strings. They are also much easier to manufacture, less easily damaged, easier to repair, and far less expensive to produce and maintain.

Finally, many harps are built without either pedals or levers. These harps can only play in a single key during any given performance, though any string on a harp can be tuned to a corresponding sharp or flat before a performance and then be returned to its regular tension (key) afterwards with little effort.