Black Sabbath

Black Sabbath formed in Birmingham in 1968, and with their self-titled 1970 debut essentially invented heavy metal. Tony Iommi's guitar tone — the foundation of the entire genre — was shaped by physical necessity as much as creative choice. After losing the tips of two fingers on his right hand in a factory accident, Iommi tuned his strings down (first a half step, eventually to C# on later records) and used ultra-light strings with banjo strings on the high end, allowing him to bend notes with his prosthetic fingertips. His primary guitar was a Gibson SG Special — later a signature model — played through Laney Supergroup LA100BL heads, an amplifier specifically designed for Iommi by Laney engineer Lyndon Laney in the late 1960s. The Laney's aggressive midrange and natural compression under distortion gave songs like "Iron Man" and "War Pigs" their crushing, grinding character. For the first two albums (Black Sabbath and Paranoid, both 1970), Iommi also used a Dallas Rangemaster treble booster — the same germanium boost pedal used by Brian May and Rory Gallagher — to push the Laney into heavier saturation. On Master of Reality (1971), Iommi detuned to C# standard for the first time, creating the sludgy, bottom-heavy sound on "Into the Void" and "Sweet Leaf" that became the blueprint for doom metal. He also used a Tycobrahe Octavia and a modified Rangemaster on selected tracks. Geezer Butler's bass rig — a Fender Precision Bass through a Laney head, later switching to Dan Armstrong and Ampeg basses — provided the low-end weight, with Butler's wah-influenced playing style on tracks like "N.I.B." adding a lead-bass dimension decades before it became common. By Sabbath Bloody Sabbath (1973), Iommi had begun incorporating a Marshall JMP and experimenting with synthesizer guitar effects, though the Laney remained his primary amp. Bill Ward's jazz-influenced drumming on a Ludwig kit — looser and more swinging than his successors in metal — gave Sabbath a rhythmic flexibility that most metal bands lost when they adopted the genre's conventions.