Noise frequency: Octave bands

Define Octave band

An octave band is a frequency band where the highest frequency is twice the lowest frequency. When more detail about the source of sound is required, a common approach is to look at the sound level at various different frequencies, that are making up the overall level. 

In the example below, 1:1 octave bands provide a breakdown of the sound level in dB, across 10 frequencies, highlighting that the dominant frequency is at 250Hz. 

Whereas 1:3 octave bands provide a more granular breakdown, with 30 frequency bands as opposed to 10. 

As part of some development applications, environmental management plans and/or operational licenses, noise levels are set at specific frequency bands, most commonly setting specific thresholds for low frequency noise.