Acoustics is the generation, manipulation, control, transmission and detection of sound and vibration.
Built-environment acoustics is evolving from passive noise surppression to the active design of positive sound environments which enhance public well being and mental health.
Noise has a significant impact on mental health therefore managing sound is central to the design and construction of domestic and commercial buildings
A frequency of 1 Hz refers to one wave cycle per second, while 20 Hz refers to 20 per second, where the cycles are 20 times shorter and closer together.
A ‘frequency band’ is a continuous range of frequencies between stated upper and lower limits. An ‘octave band’ is a frequency band in which the upper limit of the band is twice the frequency of the lower limit. A ‘one-third octave band’ is a frequency band in which the upper limit of the band is 2 times the frequency of the lower limit.
Sound intensity is measured in Decibels (dB). This is a logarithmic scale in which an increase of 10 dB gives an apparent doubling of loudness.
What is a Dn,e,w sound reduction figure?
A Dn,e,w figure reflects testing at every frequency and it is the only result recommended by the BRE for products such as vents.
As there is no industry standard for presenting acoustic test results, beware of any manufacturer who quotes an unspecified dB figure.
An unspecified figure may simply be the highest dB achieved at an individual frequency and may not bear any relation to your circumstances or to the type of noise you are aiming to reduce.
Only a Dn,e,w figure gives you peace of mind that the result reflects the true performance of the product.
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