John Paul Young broke through on the strength of his boy-next-door earnestness, which was already firmly in place on his 1972 debut, “Pasadena.” Helmed by the songwriting and production team Harry Vanda and George Young, it was the first in a string of gems Young cut with that savvy duo. His vocals turned more ragged and growling on 1975’s “Yesterday’s Hero” and 1976’s “I Hate the Music,” evoking pub-rock swagger. Young found a home in disco with 1977’s “Standing in the Rain,” which rides a jittery, mechanical rhythm for more than a full minute before his vocals enter. The same year’s “Love Is in the Air” became a hit at home and abroad in 1978, pairing Young’s grounded delivery with itchy percolations and bright melodic flights. The song has remained his signature ever since, especially after a dance-friendly new mix was prominently used in the 1992 Australian movie Strictly Ballroom.