About Acoustics

Understanding Impact (Footfall) Noise

Impact noise is increasingly becoming the most common noise complaint around the world. Typically this would be in the form of footfall noise between floors in apartments. Although one of the most difficult to deal with Impact Noise can be effectively treated if the correct techniques are used. This type of noise problem is always best treated at source and is much easier to deal with if the floor has a carpet finish. By looking at the pictures below you can see how treating and not treating the floor effects the level of sound which passes through the construction.

Before Sound Proofing Treatment

After Sound Proofing Treatment

Floating Floors

The term ‘floating floor’ is widely used for many types of products and systems. Usually these all have the same common effect, separating the sub floor and the final floor finish via an impact absorbing layer. The impact absorbing layer cushions the impact so that much less energy is delivered to the floor and into the structure. Floating floors can be created on concrete or timber constructions and can be finished with tiles, hardwood, laminate flooring, carpet, etc. Look at the list below to see which products can be used as a resilient layer to create floating floors

  • Milford Supplies RLOS
  • Milford Supplies Acoustic Batten
  • Milford Supplies
  • Acoustic Deck

Effect of floating floors

Resilient layers used to create floating floors keep energy from reaching the sub floor below. The impact is cushioned so that less energy is delivered into the floor and into the structure. High frequencies are reduced much more effectively but the effect decreases as the frequency declines. The main benefit from resilient layers is that they help reduce the energy of sound in all directions.

Using resilient mounts

Resilient mounts or Resilient Bars can be very effective in helping reduce impact noise passing through a ceiling be creating mechanical isolation and reducing the possibility for conduction. Resilient Bars are limited to only reducing the noise going directly through the floor but when used in conjunction with a resilient mount, such as Milford Supplies Iso Mat, the results can be very positive. To get the best from resilient mounts always make sure you have dealt with any flanking paths. A construction can only perform as good as the level of Flanking Noise. In some cases this may require the treatment of the walls in the receiving room.

Damping or Viscoelastic Damping

Damping is a very effective and cheap method for reducing impact noise. It works by lowering the amount of noise generated by an impact by dissipating vibration quickly as it moves through the structure, thus lowering impact noise. Damping is quite unique in that it is effective at reducing noise levels across the entire frequency range with no noticeable weakness at low frequency. By dissipating the energy it mitigates flanking noise and minimizes the level of structural noise going through the construction. The use of damping should only really be reserve for floor constructions. Although damping techniques can be used for ceilings, like Resilient Bars, damping materials can’t reduce the amount of noise created at source or help reduce flanking paths when not in the floor.