The Science of Sound Part VII: Beating Flanking Paths


In dealing with sound transmission, there’s no substitute for quality construction materials: simple mass is what stops sound waves. Naturally, stud and drywall construction is going to have a higher STC than 1/4″ hardboard paneling. Extra attention to quality techniques will pay off in sound control and ensure a good fit for the partitions.

Above all, the best defense against flanking paths is careful planning in the early stages of the project. An excellent guide to recommended installation instructions is ASTM Recommended Practice E557* which includes such issues as:

  1. Flat, level floors
  2. Level track, suspended from a non-sagging structure
  3. Sealed, insulated plenum barrier
  4. Plumb end walls or adjustable jambs
  5. Indirect HVAC ducts

Using a screed when pouring a ballroom floor, for example, keeps the floor even and level for the seals. Building a barrier in the plenum above the partition track with a construction as good as the partition itself will prevent the sound from leaking over the top. The permanent walls in which the movable partitions intersect must be vertical and braced so that the horizontal pressure does not force the partition to become uneven.

Although wall insulation (glass or mineral wool) is not an effective barrier, adding it in the cavity of wall greatly improves its performance. It is also useful above the suspended ceiling to reduce reverberation.

Both the supply and return air ducts should branch from main lines outside the rooms containing movable partitions, rather than running directly from one side to the other. If this is not possible, using lined ducts with a zig-zag pattern will help somewhat.

Who Needs Floor Tracks?

Because of the way our interior movable wall systems are designed and engineered, we don't have the need for floor tracks. Just like you don't have the need to trip and fall, we don't have the need for floor tracks. One of our Hufcor Marketing Product Managers, Rick Woods explains why.

The Science of Sound Part VII: Beating Flanking Paths

The first step to beating flanking paths is to look at how all of the elements work together from floor to roof-the partition, the space between the ceiling and the roof, the floor, even HVAC ductwork can help or hinder flanking paths.

The Science of Sound Part VI: Flanking Paths

Shoddy construction, customary construction practices, or poor installation of the partition can all contribute to the leaks, known as flanking paths.