Relinquishing control can be one of an artist's greatest challenges, but it can yield the greatest rewards. For Merrill Garbus, the Oakland singer-songwriter better known as Tune-Yards, that process was pivotal in the creation of her sophomore album, w h o k i l l, released in April on 4AD. Unlike her first full-length, 2009’s BiRd-BrAiNs, which a solo Garbus assembled piecemeal on a voice recorder, this latest effort was made in a traditional studio environment, in collaboration with bassist Nate Brenner, who cowrote several songs. Free from the occasionally encumbering lo-fi trademarks, w h o k i l l is a standout folk-pop experiment, spanning musical traditions while demonstrating Garbus’s dexterous voice and fiercely concocted arrangements. Sharing the bill is the Suite Unraveling, an artful jazz-rock combo led by guitarist Lily Maase.