Barbara Kinzle and Birch Cooper, the Portland, Oregon duo, The Slaves, only have a handful of releases under their belt so far, but they have learnt how to fit real well within each other’s movements, piling on in all the right places and knowing when to pull back. Their formula is simple: guitar, synth, voice. The Slaves debut “River” off forthcoming Spirits of the Sun LP out on Digitalis this July.