290 Triple Layer Acoustic and Fire Speaker Hood

It is a legal requirement for all in-ceiling speakers that fire hoods are installed below any habitable rooms or means of access or escape. A standard two storey house will require all the ground floor speaker locations to have hoods fitted. If a house has three storeys, you will need hoods on all ground floor speaker and first floor speaker locations to correctly comply with the regulations.

The majority of ceiling speakers have a cut-out diameter ranging from 200-250mm. The Lithe Audio acoustic hood has an aperture of 200mm but can be enlarged by simply cutting the fabric. A guide is marked on the flange which is the typical diameter of an 8-inch driver speaker. There is a sewn seam to keep the fabric neat. It is preferable to avoid cutting this seam.

Firstly, it makes the hood easier to fit but, more importantly, it performs significantly better because it is possible to create a much more effective seal. An effective seal means that way the fire protection performance is maximised, as is the acoustic performance. Even a small gap under the flange weakens both of these aspects considerably. Dust ingress is also minimised thus protecting the speaker better too.

The Lithe Audio acoustic hood is compressible without affecting its performance. Providing your speaker itself has sufficient clearance, you only need 2-3mm additional clearance to accommodate the fabric of the hood. Although the extended height of the hood can accommodate speakers with a depth of up to 200mm, it can be compressed to comfortably accommodate speakers with a smaller depth requirement. In short, the hood will fit almost any depth of speaker typically used in ceilings.

In an ideal world all speakers would be central to the joists. If this isn’t possible, then there are two options you can do. The first is simply to scrunch the fabric of the hood against the joist so that the speaker will fit. This will not affect the performance of the hood or speaker. If the aperture is too close to the joist to allow this then the second approach is to cut the fabric of the hood to create an offset (elliptical) aperture. Again, this will not affect the performance of the hood. In this case it may be necessary cut through the sewn seam on the flange and this will expose some of the foam. You may need to then glue this back in place.

We estimate the typical sound reduction to be of the order of -9dB following the addition of our hood. This will vary from installation to installation and so this is a guide only.