Drenal's Sound Barrier

This spell creates a transparent barrier through which no sound can pass. When this wall is placed so as to block an entire portal, passage, or hole, no sound can pass from one side to the other. The sound barrier must be anchored to four surfaces. The desired effect is possible only when the entire passage is covered, and sounds will not easily travel through the surrounding walls. The barrier can be horizontal or vertical.

The casting of this spell involves sticking small soft clay mounds that have feathers stuck in them, in two corners of the area to be blocked (such as the corners where a door meets the floor), to form a base for the barrier.