After Iceland’s Sigur Ros announced their official indefinite hiatus at the beginning of this year, the void was palpable. Known for the pageantry of their performances and a steady release of sweeping, orchestral albums, Sigur Ros set the bar for post-rock outfits touring with a theme in mind. So it made sense when the band’s founder and front man, Jonsi Birgisson, struck out on his own, that little of the spellbinding beauty that characterizes Sigur Ros’ best known work would be sacrificed. When Jonsi came through D.C. to the 9:30 Club for a two-night stand this week, longtime fans of Sigur Ros and newcomers to Jonsi’s sound could not have been disappointed.