Flanking Paths in Home Cinema Installations - November 20th, 2008
Flanking paths, which are the main limitation to sound isolation in home cinema installations, arise when there are other paths that the sound can travel through, in order to get round the sound isolating structure. Typical paths for flanking in a home cinema installation are the building structure, heating pipes, and most commonly ventilation systems or air leaks.
Home cinema designers can reduce the effect of the building structure by building a ‘floating room,’ which removes the effect of the building structure by floating the room on springs away from it. In practice, ensuring that no part of the building is touching the dedicated home cinema room by any means (plumbing pipes and electrical wiring conduits are popular offenders in this respect) is extremely difficult.
The effect of ventilation systems and air leaks are also a major source of flanking in many home cinema installation cases. In fact in the domestic situation the sound isolation is almost entirely dominated by air leaks and draught paths, and it is the removal of these that allow double glazing salesmen to advertise a dramatic improvement in sound isolation, despite having two 4 mm panes of glass in the double glazing.
So in order to have good sound isolation in home cinema installations, one needs good partitions and an air-tight, draught-free structure. Achieving this in practice, while still allowing the occupants in the home cinema to breathe is a challenge.