Din of the Damned

Level III Rituals
Description: This ritual is similar to the Level One Ritual Call of the Hungry Dead in that it makes the sounds of the underworld audible in the physical realm. However, Din of the Damned is an area-effect ritual used to ward a room against eavesdropping. Over the course of half an hour, the necromancer draws an unbroken line of ash from a crematorium along the room's walls (this line may pass over door-frames to allow entrance and egress). For the rest of the night, any attempt to listen in on events inside the room, be it simple (a glass to the wall), electronic (a laser microphone), or mystic (Heightened Senses), requires the eavesdropper to score more successes in a Perception + Occult roll (difficulty 7) than the caster of the ritual scored. Failure to beat this mark gives the listener an earful of ghostly wailing and moaning and the sound of howling winds; a botch deafens him for the rest of the night.
Reference: Guide to the Sabbat