Though Curved Air never broke through to the level of fame attained by the likes of Yes or Genesis, the band caused quite a stir on the British prog-rock scene when it emerged in the early ‘70s. A major factor in the U.K. success of its 1970 debut album was the charismatic presence of Sonja Kristina, one of the first female prog vocalists. Curved Air was also among the first rock bands to prominently feature a violinist; Darryl Way’s work here is a crucial element, whether he’s going toe-to-toe with Francis Monkman’s lead guitar lines on the hard-edged “Stretch” or laying down elegant, classical-influenced melodies on the winningly understated “Blind Man,” which veers closer to Left Banke–style baroque pop than prog. Speaking of classical influences, Way’s near-maniacal sawing on “Vivaldi,” an instrumental homage to the Italian composer, remains one of progressive rock’s most gloriously unhinged moments. It also hints at the rawness and visceral quality running through Air Conditioning that help it stand apart from the contemporaneous proggy pack.