Glasgow’s Richard Youngs has never been afraid of challenging his listeners. For Amplifying Hosts, the prolific songwriter works with Galaxie 500’s Damon Krukowski on a deliberately slow-paced set where harmonies hang in the air like smog. “Tessellations” begins with discordant folk, voices echoing off wandering guitar lines and aching horns. “Holding Onto the Sea” kicks up the pace ever so slightly. “Too Strong for the Power” manages a sublime hypnosis broken up by an errant trumpet. Casual folk or ambient fans are likely to be jarred awake by the daring textures and aggressive notes. However, if one can accept the unusual tonal clusters, there is an odd beauty in the restless cadence of “This is the Music” and “A Hole in the Earth.” After the relative “pop” of his previous album, 2010’s Beyond the Valley of Ultrahits. Amplifying Hosts is a return to dark ground.