Powerpop is a popular musical sub-genre that draws its inspiration from 60s British and American pop and rock music. With the term defined by Pete Townshend of The Who, it typically incorporates a combination of musical devices such as strong melodies, crisp vocal harmonies, economical arrangements, and prominent guitar riffs. Instrumental solos are usually kept to a minimum, and blues elements are largely downplayed. Recordings tend to display production values that lean toward compression and a forceful drum beat. Instruments usually include one or more electric guitars, an electric bass guitar, a drum kit, and sometimes electric keyboards or synthesizers. While its cultural impact has waxed and waned over the decades, power pop is among rock's most enduring sub-genres. The music often over-laps with other rock sub-genres such as new wave, pop punk, jangle pop, and general pop rock among others.