The Archtop Guitar is an acoustic or electro-acoustic guitar with steel strings and a peculiar curved shape in its top; its sound is highly popular in the Jazz and Blues world.
Its origin is usually attributed to Orville Gibson, being later perfected by Lloyd Loar, who transferred ideas from classical instruments such as violin to a new design that was called archtop.
Most commonly, spruce wood is used for the top, which is usually carved by hand, although some manufacturers use plywood tops even on high-end instruments. The sides and backs are usually made of maple, in the style of classical stringed instruments.
Although originally all Archtops were acoustic, electric models began to be sold from the middle of the 20th century.
Tonally, it has a mellow and warm sound.
In addition to the curvature, another detail that makes the Archtop different are the harmonic holes, similar to the instrument of the violin family.