A lap harp is a stringed instrument of the plucked psaltery family. It is so named because the player positions the harp on his lap to play. Due to the positioning of the instrument, lap harps are smaller than their larger cousin, the pedal harp, which sits on the floor. People have played various versions of lap harps around the world for thousands of years.
Lap harps fall into two basic categories: non-levered and levered. A non-levered lap harp is very simple in that the strings stretch across the instrument and attach to tuning pegs. If the player wants to play in a key different than the one to which the harp is tuned, he must use a separate tuning tool to turn the tuning peg and adjust the pitch of at least one string. This isn't usually very practical to do quickly or often, so most non-levered harps are tuned to C or G, which allows tuning to a handful of other keys by adjusting only one or two strings.
A levered lap harp attempts to eliminate the cumbersome task of adjusting the harp's tuning pegs to change keys. This type of harp has a lever mechanism that connects to the string. When the player activates the lever, the lever pulls on or releases the string, thereby changing its pitch up or down one half step. The lever mechanism moves only in one direction, however, meaning that it can do sharps or flats but not both.
Lap harps further can be categorized based on the exact playing position. Some lap harps sit entirely flat on the lap, which places the strings in a horizontal position and requires players to have their hands palm down while playing. The melody harp, a very simple, non-levered lap harp with a trapezoidal shape and only 15 or 16 strings, is probably the best and most common example of a "flat-sitting" harp; it closely resembles a dulcimer. Most lap harps are "edge-sitting" harps, meaning the harp sits on end with the strings in a vertical position and that the palms face inward to play. Edge-sitting harps may be non-levered or levered, but a high-end edge-sitting harp usually has a full lever system allowing the player to address all seven keys possible.
Flat-sitting harps such as the melody harp are restricted in size to accommodate the length and width of the player's lap. With an edge-sitting harp, size is more variable because there is nothing preventing the strings from rising to different vertical heights. A small edge-sitting harp can be under 2 feet (61 cm) and weigh 5 pounds (2.27 kg) or less, but a height of 32 to 36 inches (81.28 cm - .9 m) is more common. Larger versions can have up to 25 strings and weigh 10 to 12 pounds (4.5 - 5.4 kg).
The range of a concert or pedal harp extends about five and a half octaves, as this type of harp has an average of 45 strings. The largest lap harps, by contrast, usually have a range of about three octaves. Translated into practical performance, this means that lap harp players are more limited with the music they can play and the effects they can achieve. The limited range and small size of lap harps, however, makes them much more portable and lighter than larger harps, which is advantageous for individuals such as music therapists who must take their instrument to different locations frequently.
Although a high-end lap harp can play in every key and is easy to transport, it still has one major problem: to shift a lever during performance, the player has to stop playing with one hand. Around the end of the 1600s, harp makers solved this problem by creating harps with pedal mechanisms. The pedals, which a player operates with her feet, connect to a mechanism that, similar to the lever, manipulate the length — and therefore the pitch — of the harp strings. Levered lap harps thus represent the mid-point in harp technology, with modern pedal harps being able to adjust pitches to achieve both sharps and flats.