Glasgow folksinger Alasdair Roberts has never comfortably settled into the traditionalist role. Formerly with Appendix Out and as an official solo act, he has often punctuated his traditional-sounding folk songs with rock instrumentation or the kinds of conceptual ambitions that would seem more fitting for a progressive rock fan. He’s essentially a musician without an easy genre to settle in. Yet he doesn’t challenge so many conventions as to make his music unlistenable. Not at all: This four-song EP, which follows his ambitious and diverse 2009 album Spoils, is exceptionally stripped down. Yamaha synths are listed among the credits, but mostly it’s acoustic guitars with an occasional harmonium swelling underneath. Drums, electronics, and backing vocal chants poke midway through the seven-minute “The Royal Road at the World’s End,” but the song’s purest soul is the forlorn ageless melody. The remaining three tunes reveal themselves slowly in their solemnity. Roberts doesn’t have an era or a musical movement to belong to, making his loner status that much more appealing and ear-turning.