Pedal harp

The pedal harp (also known as the concert harp) is a large and technologically modern harp, designed primarily for use in art music. It may be played solo, as part of a chamber ensemble, or in an orchestra. It typically has 47 strings with seven strings per octave, giving a range of six and a half octaves.

In this type of harp the pedals alter the pitch of the strings, so that the pedal harp can easily play works written in any key. This is particularly important in the harmonically complex music of the Romantic period and later 20th-century classical music.

A pedal harp typically stands about 1.8 m (6 ft) high, is 1.2 m (4 ft) deep, and 55 cm (21+1⁄2 in) wide at the bass end of the soundboard. It weighs about 36 kg (80 lb).

The body of the harp consists of a straight upright pillar, sometimes adorned with a crown at the top; a soundboard, which in most harps is pear-shaped with additional width at the bottom, although some older instruments have soundboards that are straight-sided but widening toward the bottom; a harmonically curved neck containing the mechanical action made up of over 1,400 parts; and a base with seven pedals.

The D, E, G, A, and B strings are normally colored white, while the C strings are colored red and the F strings either black or blue. The lowest strings are made of copper or steel-wound nylon, the middle-lower of catgut, and the middle to highest of nylon, although more or all of the strings may be gut. The total tension of the strings on the soundboard is roughly a ton (10 kilonewtons).

Pedals for harp tuning were first introduced in 1697. The mechanical action of the pedals changes the pitches of the strings. The seven pedals each affect the tuning of all strings of one pitch-class. The pedals, from left to right, are D, C, B on the left side and E, F, G, A on the right. Each pedal attaches to a rod or cable in the column of the harp, which connects to a mechanism in the neck. When the player presses a pedal, small discs at the top of the harp rotate. The discs are studded with two pegs that pinch the string as they turn, shortening its vibrating length. In each position the pedal can be secured in a notch so the foot does not have to continuously hold it in position (unlike piano pedals).

Pedal harps are essentially diatonic instruments with the double-action pedal mechanism providing chromatic alterations and key changes. No matter how the pedals are set, the pedal harp still has only seven strings per octave and therefore can play seven notes per octave. Smaller harps, often called folk, lever or Celtic harps, also have only seven strings per octave, and use a mechanical lever on each string that the player must move manually for chromatic alterations. The only completely chromatic harps are the double (arpa doppia) and triple (Welsh) harps and cross-strung harp.

The double-action pedal system was first patented in London by Sebastien Erard in 1801 (patent number 2502) and 1802 (patent number 2595). In 1807 Charles Groll was the first to register a patent (patent number 3059) where the harp mechanism was doubled with two lines of fourchettes (forks). Earlier pedal harps had a single-action mechanism that provided only sharped notes, the first of which was made in 1720 by Jacob Hochbrucker in Bavaria.