Air leaks and ventilation paths defeat sound isolation more than walls do

Evidence

Flanking paths, which are the main limitation to sound-isolating structures, arise when there are other paths that the sound can travel through in order to get around, that is, flank, the sound isolating structure, as shown in Figure 6.57. Typical paths for flanking are the building structure, heating pipes, and, most commonly, ventilation systems or air leaks. The effect of the building structure can be reduced by building a “floating room,” as shown in Figure 6.58, which removes the effect of the building structure by floating the room on springs away from it. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2124

Categorization

• DEFINE: Defines ‘flanking paths’ — the core concept for why sound isolation fails — and gives the floating-room countermeasure.
• XREF: Connects to the reader’s interest in why silence is hard to achieve; physical leakage, not wall mass, dominates real-world isolation. — connects to: Sound isolation depends on flanking paths more than the barrier itself — David Howard, Jamie Angus, coustics and Psychoacoustics, 2169; In homes, air leaks dominate sound isolation more than the glazing itself — David Howard, Jamie Angus, coustics and Psychoacoustics, 2173; Flanking transmission paths, not the partition itself, limit sound isolation — David Howard, Jamie Angus, coustics and Psychoacoustics, 2170