Music critic William Ruhlmann describes "Purple Haze" as having "relentlessly driving, if relatively slow-paced underlying music, which provides a good platform for some of Hendrix's inventive guitar playing". Beginning with its dissonant opening and heavy use of distortion, Hendrix's techniques "all contributed to the dirty, raw, metallic, angular sounds" heard in the song, according to Shapiro. The intro consists of the melodic interval of a tritone or diminished (sometimes called flattened) fifth. Historically, this dissonant interval has been referred to as "diabolus in musica" (literally "Devil in music"). It is sounded during the first two measures by Hendrix playing a B on guitar against an E played by Redding on bass, followed by the respective octaves. Mitchell on drums comes in for the third measure, when Hendrix introduces the riff that piqued Chandler's interest, and Redding continues playing the octaves in E.