You Keep Me Hanging On

Proto-metal is the late-1960s hard, heavy strain of rock that crystallized the sonic vocabulary later codified as heavy metal. It bridges blues-rock, garage rock, and psychedelic rock with louder amplification, thicker distortion, and riff‑centric songwriting. Musically, proto-metal emphasizes power-trio or organ/guitar lineups, pentatonic/blues-derived riffs, power chords, and aggressive, often fuzz-saturated tones. Vocals can range from soulful shouts to theatrical wails, and rhythms often push straight 4/4 grooves at mid-to-up tempo with a palpable sense of weight and drive. Historically, it includes bands whose heaviest work predated metal as a named genre, as well as early albums by future metal standard-bearers. Its sound laid the groundwork for the timbre, riff language, and attitude of heavy metal and, by extension, numerous metal subgenres.

Acid rock is a heavier, louder, and more improvisation-driven branch of psychedelic rock that emerged in the mid-to-late 1960s. It is characterized by extended guitar solos, distorted and feedback-laden textures, modal or drone-based harmony, and a strong emphasis on trance-inducing grooves. The style was closely tied to the counterculture and LSD-fueled happenings of the era, particularly on the U.S. West Coast. Musically, it blends blues-rock’s grit, garage rock’s raw energy, folk-rock’s modal harmonies, and raga-influenced drones, then amplifies everything—volume, duration, and intensity—into hypnotic, often explosive performances.