O Saala Sakraal is a Dutch collective that combines dark ambient and post-industrial leanings into a unique union of sounds and textures. Heven, an EP-length effort and second from the group, centers around a four-piece choir that chants both with lyrics and wordlessly. The voices are combined with deep drones that, unlike some uses of that technique, evoke a sense of movement and urgency. Atop this is percussion that is kit-based and also employs found objects, ultimately sounding more than a little like F.M. Einheit from Einstürzende Neubauten. These recordings drip with tension even when the tempo decelerates to a slow burn. The spoken-word passages are somewhat less initially compelling than the choral and percussion-oriented sections, but add to the psychologically haunting atmosphere of the pieces. Overall, this is a very well-done, weird, and disturbing short album.