The music of the '60s has been mined so thoroughly it's a wonder that there's anything left to use. That never seems to have occurred to The 1900s, a seven-piece, boy-girl Chicago band that makes psychedelic pop songs that sound pleasingly simple despite the layers of instruments that go into making them. The band's bio alludes to "Fleetwood Mac-style breakups," but any friction behind the scenes translates into sweet harmony on its full-length debut Cold & Kind. The album develops nicely on the promise of last year's Plume Delivery EP, fleshing out the sound, finding new ways to weave the vocals, and slipping unsettling sentiments into its sunny melodies, taking a classic sound and confidently tilting it to a modern angle.