Some bands curate an intentionally old-school sound, while others take that sound and make it fit right in with today’s world. Indie rockers Gringo Star describe themselves as “insouciant explorers,” and their sound bears that out, digging through the past for inspiration. That tendency continues, the Atlanta outfit fusing classic rock touchstones with modern indie and garage rock on their latest, The Sides and in Between. The roots of Gringo Star’s sound come from brothers Peter and Nick Furgiuele’s conversations with their grandfather, who was playing R&B on the radio back in the days of segregation in the ’40s and ’50s. They got a slight update in the studio from Grammy award-winning producer Ben Allen, the producer behind their first two albums, 2008 debut All Y’all and 2011’s Count Yer Lucky Stars. On Floating Out To See, the Furgiuele brothers went out on their own and experimented further with a garage rock twist. For The Sides and In Between, Gringo Star try to have a little bit of both: a throwback to early rock ‘n’ roll and a kick of grunge. Despite the push-and-pull of those diverging elements, their songs wrap up in brief, three-minute packages. This works in Gringo Star’s favor, allowing them to focus on simple ideas rather than drawing it out any further than it needs to.