Broner, N. A Simple Outdoor Criterion for Assessment of LFN Emission
N. Broner, Sinclair Knight Merz
Acoustics Australia, April 2011
“Complaints about the effect of higher level Low Frequency Noise (LFN) in the form of rumble, a “feeling of pressure” and resultant headaches and nausea have been known for decades [1,2]. Human hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive LFN, that is, to perceive frequencies below 100 Hz, the sound pressure level must be relatively high when compared to that for mid frequency noise, e.g. 500–3000 Hz.
As the frequency decreases toward the infrasonic range (frequencies less than 20 Hz and a subset of LFN), the sensation of hearing changes to one of a feeling of ear pressure and envelopment for those noises which exceed the hearing threshold.
It can be said that the effects of LFN are broadly similar to those of high frequency noise in the sense that any unwanted sound is potentially annoying. However, LFN exhibits itself in the form of “rumble” and “pressure” and while not at all loud in the normal sense of the word, LFN can exacerbate the annoyance reaction when compared to higher frequency noise, especially when the noise is perceived to be “fluctuating” or “throbbing”.”