LISTENING STATION: Edward Sharpe, Sigur Ros

Is that a Gregorian choir during the intro to “Eg Anda,” or is it a wall of gauzy, reverb-laden guitars? Who knows. It’s hard to make out any definite shapes, and while that’s probably the whole point of a spectral album like “Valtari,” the ambience feels a little hollow at points. Understatement is a fine tool, but these songs minimize the band’s talents to the point of nonexistence, bypassing all the string sections and cinematic arrangements that turned albums like “Ageaetis Byrjun” into minor masterpieces.

Do the guys in Sigur Ros know what sort of impressionistic picture they’re trying to paint, or are they simply splashing pools of muted color onto the canvas, hoping a shape will eventually take hold? It doesn’t, and “Valtari” winds up accepting its role as hip, forward-thinking mood music, ideal for the background but rarely worthy of any heavy observation up close.