A pedal harp, also called a concert harp, is a stringed instrument of the plucked psaltery family. They are the most technologically advanced of the various types of harps. For this reason, it is the pedal harp that most often is used in professional concert settings, although some musicians specialize in performing on other harp types.
The most basic forms of harps are comprised of strings that stretch across the instrument, attaching to pegs. The size of the harp generally determines the number of strings. A problem with these harps is that there often isn't a good way to prepare the instrument to play in multiple keys. To do this, players have to manually re-tune at least one string by turning the peg to which it attaches. A solution was to add a lever mechanism to the strings that could let players change the length of the string very quickly and thereby change the tone of the string by one half step.
Although professional lever harps can adjust every pitch, they have limitations. The lever harp works by shortening the length of the string when the lever is open. The player can move from flat to natural and back or natural to sharp and back, but cannot achieve all three notes of a pitch class, such as Gb, G and G#.
A second difficulty of the lever harp is that, in order to adjust the lever, the player has to move at least one hand off the strings while playing. If a player has some rests before the change must occur, this is not a huge problem. If there are no rests, however, it is not always practical.
In recognition of the problems posed by basic and lever harps, people developed pedal harps at the very end of the 1600s. This type of harp has a set of pedals on the base of the harp. The pedals connect to an intricate mechanism inside the harp that essentially replaces the manual levers in lever harps. The player can adjust the pedals either up or down, which means that it is possible to get both sharps and flats. While performing, the harpist controls the pedals with his feet, leaving his hands free to continue playing.
In music, pitches fall into one of seven classes, designated by the letters C, D, E, F, G, A, and B. By raising or lowering one or more of the classes by one half step, it is possible to play in different keys. Thus, a pedal harp has seven pedals, one for each pitch class; three pedals are on the left and four are on the right. Players are able to play in any key as a result. The pedals control each pitch class at all octaves, so it would not, for example, be possible to play a C and C# at the same time.
The fact that a pedal harp moves adjustment of the strings to the feet of the player means that the harp cannot sit on the lap of the player the way other harps can. Subsequently, a pedal harp can be larger than other harps, have more strings — most modern pedal harps have a total of 47 strings — and enjoys a greater range of playable music. The larger size of the pedal harp does mean that the instrument is heavier, however, which makes it less portable.
Pedal harps have a sweet, almost bell-like tone, but the sound varies slightly based on the material from which the strings are made. Gut strings generally are mellower than nylon ones. Pedal harps blend well with other instruments and thus are used in small and large ensembles in addition to acting as a solo instrument. Despite the angelic nature of the harp's sound, the instrument is capable of surprising volume.