On a recent camping trip in the UK, in our motorcamper, Joy, my wife and I experienced two disturbing night time noises, one on each camp site, which disturbed first Joy on Campsite one but not myself .This was the mid frquency noise of traffic on the nearby motorway
Whilst on campsite two I was disturbed while Joy was only mildly affected. In this case the noise was a low frequency hum which I eventually traced as coming from an electric motor on the campsite sewage plant.The plant was about 200m from our caravan and the low frquency hum was not audible outside our van but was quite distinctive within it. This phenomen of inaudiblity outside a dwelling but audibility within it is due to resonances with in the structure being excited by and "amplifying" the noise. It can can result in the noise being particularly disturbing to those sensitive to such a low frquency noise especially when it is not obvious what is causing the noise or where it may be coming from.
The situation for the two sites and our responses is summarised in the table below.
|
Camping noise source |
Campsite one Motorway traffic |
Campsite two sewage system |
|
|
noise type
|
mid frequency drone
|
low frequency hum
|
|
|
Reaction |
"Intrusive" |
"Annoying" |
Mike
|
|
Action
|
Turn over & sleep
|
Find source & then sleep
|
Mike
|
|
Reaction
|
"Annoying"
|
"Quiet"
|
Joy
|
|
Action
|
wear earplugs to sleep
|
sleep
|
Joy
|
Why should there be this real and marked difference between people in their reaction to different types of noise?
|
Feature
|
Mid frequency noise |
Low frequency noise |
|
Sources
|
Traffic, aircraft, people , music, animals etc
|
Often unknown Domestic Fridge/freezer,ssewage, air conditioning systems, oil fired boilers |
|
Noise quality
|
various
|
hum. rumble, throb
|
|
Noise levell
|
30-85dBA
|
<20dBA
|
|
Most sensitivie personality type
|
Gut/Heart*
|
Not known
|
|
Least Sensitive personality type
|
Head*
|
Not known
|
|
Important factors in determining annoyance
|
Noise level, personality type, Sensitisation |
Room resonance, unknown origin, personality type, Sensitisation, Not easily masked |