A melody harp is a plucked psaltery instrument. It belongs to the folk and lap categories of harps and is inexpensive compared to other types of harps. It is one of the simplest versions of a harp available and thus is very easy to learn. Due to the limitations of the melody harp, however, most players use the instrument for fun and don't use it in professional musical settings.
The melody harp has two major distinguishing characteristics compared to other instruments in the harp family. The first is its overall shape. The instrument is usually trapezoidal, whereas most other harps are more triangular. Shorter strings are strung across the smaller end, or top, of the trapezoidal shape, so the lowest pitches are at the bottom of the harp. The higher-pitched strings usually are placed furthest away from the performer's body while playing.
The second distinguishing characteristic of a melody harp is that the entire melody harp sits flat on the lap or on a table, meaning the strings are positioned horizontally while playing. This is the opposite of other types of harps, which sit on end with the strings in a vertical position. The way the melody harp sits requires the hand to be positioned palm down for plucking or strumming the strings. The need for the melody harp to fit in the lap in this way also is largely what has dictated the general size of the instrument.
The range of a melody harp, due to the instrument's small size, is relatively limited. Most "standard" melody harps have 15 strings, although some have 16. A single octave in music spans eight pitches from start to finish, such as C, D, E, F, G, A, B and C. Melody harps, therefore, usually span only about two octaves. Some people see this as a major disadvantage because it severely limits the music a person can play. Others see it as a major advantage, as the simplicity of the instrument makes it easy for even young children to learn quickly.
Melody harps are concert or non-transposing instruments, meaning that the note played is the same on paper as it sounds. This is the opposite of transposing instruments, which produce a different pitch than the written one the player sees on the page. Melody harps may be tuned to different keys, however, the most common of which are C and G.
Some members of the harp family have levers that connect to the strings. The levers let the player alter the length of the string and thereby change the pitch by one half step, which makes it possible to shift very quickly from one key to another, even in the same piece of music. Melody harps usually do not have levers, so if the player wants to play in more than one key, he has to re-tune at least one string on the harp manually with a tuning lever that fits over the peg to which the string is attached. This is not practical to do while playing, so melody harps cannot perform music where the key shifts as the music progresses.