‘I feel the bones of how we used to be,” sings Sophie Allison on her third album as Soccer Mommy. It’s not a reference to her creative process – it’s the opening line of a song about a failing relationship – but it does feel oddly apropos the music she makes. At 25, Allison is more of an indie traditionalist than most of her US alt-rock peers. Her sound comes unsullied by diversions into glossy 80s synth-pop, faux R&B or knowing pastiches of 70s singer-songwriter soft rock. It has thus far stuck to a template rooted in the early 90s: lazily strummed electric guitar, honeyed vocals and, occasionally, the swirling, echoey atmospherics of shoegazing, sounds that are all present and correct on Sometimes, Forever.