Heavy metal music styles in its early years, but by 1969 vocalist Ian Gillan and guitarist Ritchie Blackmore had led the band toward the developing heavy metal style. In 1970, Black Sabbath and Deep Purple scored major UK chart hits with "Paranoid" and "Black Night", respectively. That same year, two other British bands released debut albums in a heavy metal mode: Uriah Heep with "...Very 'Eavy ...Very 'Umble" and UFO with "UFO 1". Bloodrock released their self-titled debut album, containing a collection of heavy guitar riffs, gruff style vocals and sadistic and macabre lyrics. The influential Budgie brought the new metal sound into
Heavy metal music tone, typically in the bass range, during which at least one foreign (i.e., dissonant) harmony is sounded in the other parts. According to Robert Walser, heavy metal harmonic relationships are "often quite complex" and the harmonic analysis done by metal players and teachers is "often very sophisticated". In the study of heavy metal chord structures, it has been concluded that "heavy metal music has proved to be far more complicated" than other music researchers had realized. Robert Walser stated that, alongside blues and R&B, the "assemblage of disparate musical styles known ... as 'classical music has been a major influence