Led Zeppelin II was recorded fast during Led Zeppelin’s initial American tours, and it served as a pattern for all heavy metal bands that followed. Because the band could only spend a limited amount of time in the studio, the majority of the songs that make up II are modified blues and rock & roll standards that the band was performing live at the time. Not only did the lack of unique content result from the limited amount of time, but it also made the sound more direct. Although Jimmy Page contributed layers of guitar overdubs, the album’s overall sound is heavy and aggressive, brutal and direct. “Whole Lotta Love,” “The Lemon Song,” and “Bring It on Home” are all based on classic blues tunes, but with simpler and louder riffs and prolonged sections for instrumental solos. Two of the remaining six songs have mild acoustic influences (“Thank You,” “Ramble On”), while the remaining four are straight-ahead strong rock that follow the formula of the revised blues songs. While Led Zeppelin II lacks the group’s debut’s eclecticism, it is perhaps more influential. After all, with its lack of dynamics and pummelling riffs, practically every one of the hundreds of Zeppelin imitators took this album as a model.