Rectangular Absorptive Sound Attenuator



Rectangular Sound Attenuators are used in ventilation systems and are specifically designed to reduce duct born noise. The rectangular shape is especially advantageous concerning the attenuation of low frequency noise, and is effective in reducing noise generated by fans, compressors and gas turbines. By using a series of parallel acoustic baffles which splits the airstream into several passages, the unit allows a larger absorption area. In order to attenuate specific frequencies, different combinations of baffle thicknesses, lengths and passage areas may be changed to obtain desired performance.

Materials and dimensions:

The attenuators can be made in different materials and as a flange or spigot type, making it accessible for installation in a variety of situations and are recommended for use in corrosive conditions as industrial and offshore atmospheres. Special consideration is given to the design of all units which are to be used in environments of high humidity, pollution or high temperatures. Standard sizes are shown in the brochure, but all attenuators are individually designed according to the customers' requirements and non-standard sizes can be delivered upon request.

The insulation material consists of non-toxic and non-combustible mineral wool, and is firmly covered by polyester or glass fibre cloth and a perforated plate to prevent fibre migration from the wool.

Noise data:

Available noise data for the rectangular sound attenuators is based on:

  • ISO 7235- "Acoustic measurement procedure for ducted silencers - insertion loss, flow noise and total pressure loss."

The sound reduction achieved by a sound attenuator is heavily dependent on the sound field inside a duct, and is limited by the duct arrangement. This is why measurements on site will often vary from laboratory measurements, because the attenuator on site will be affected by factors as flanking noise, background noise, vibration etc. In order to get the best possible result, please contact Acoustics for accurate noise calculations for your particular need. For more information on self-generated noise for the rectangular sound attenuator, please contact Acoustics.