Modern Autoharps have 36 or 37 strings, although some examples with as many as 48 strings exist. They are strung in either diatonic (1, 2 or 3 key models) or chromatic scales.
Although the Autoharp is often thought of as a rhythm instrument for playing chordal accompaniment, modern players can play melodies on the instrument. Diatonic players are able to play fiddle tunes by using open-chording techniques, "pumping" the damper buttons while picking individual strings. Skilled chromatic players can perform a range of melodies.
Diatonically strung single key instruments from modern day luthiers such as Orthey, Fladmark, Hollandsworth, D'Aigle, Baker, Daniels and Goose Acres are known for their lush sound. This is accomplished by doubling the strings for individual notes.
Since the strings for notes not in the diatonic scale need not appear in the string bed, the resulting extra space is used for the doubled strings, resulting in fewer damped strings.
Two and three key diatonics compromise the number of doubled strings to gain the ability to play in two or three keys, and to permit tunes containing accidentals which could not otherwise be rendered on a single key harp. A three-key harp in the circle of fifths, such as a GDA, is often called a festival or campfire harp, as the instrument can easily accompany fiddles around a campfire at a festival in their favored keys.