Ghosts of Glaciers make some noise at Mouth House on Friday, July 20

Post-rock has enjoyed a certain popularity of late — and it’s easy to see why music that loosely fits that designation often gets put under of the umbrella of instrumental rock. Ghosts of Glaciers — due this Friday, July 20, at Mouth House (2858 California Street) — doesn’t bother to observe the distinction, either. Unlike certain lesser post-rock artists who basically learned to make streaming sounds with a delay pedal and a guitar of choice, there are real chops being displayed by this band’s members. Ben Brandhorst is the outfit’s secret weapon, with the dynamism to do polyrhythms — and not just the standard sort; he’ll throw in a tasteful blast beat in just the right place and render the song  especially visceral. Steven Jackson and Michael Rouse play off each other in intertwining circles, putting out introspective melodies and driving, intricate passages. Ghosts of Glaciers’ full-length debut, available at this show, is a vital fusion of post-rock and metal’s edge.