The Science of Sound Part VII: Beating Flanking Paths
Sound, like water, follows the path of least resistance. If there are leaks in the surrounding construction, even the best movable partition will not provide a good sound barrier. Shoddy construction, customary construction practices, or poor installation of the partition can all contribute to the leaks, known as flanking paths. The graphic below illustrates how flanking paths can limit even a 56 STC partition’s abilities to block sound. When a path one tenth of one percent of the total area exists, a 56 STC rating can drop all the way down to 30 STC as far as effectiveness of the partition. This is why, when we focus on acoustics, we talk about the entire system; not just the panels. A panel is only as good as the system it is part of.
KEEPING AN EYE ON DETAILS
Flanking paths can be present even when the surrounding construction is of good quality. Direct HVAC ductwork between rooms, common lobbies and corridors, and open plenums above suspended ceilings are all perfect escape routes for sound. The ceiling tiles themselves, whose porous properties help prevent reverberation, allow sound to pass through easily. Uneven floors and out-of-plumb walls also contribute to leaks as do recessed lighting, access panels, projection and lighting booths, and other design details as well.
Next week we’ll discuss how to beat flaking paths.