The loudest sound ever …
What’s the question that’s often asked at dinner parties? Something along the lines of – if an animal makes a sound in a remote forest, and no-one’s there to here it, did it in fact make a sound?
Well, of course the scientists would presumably say “yes” – a sound wave (see our last blog) was generated, and travelled through the forest, irrespective of whether anyone was there or not. Then again the philosophers might argue that, by its very definition, a sound needs to be heard! Here’s what the Dictionary says:
Sound: (noun): something that you can hear or that can be heard
So who’s right? The scientists would argue that the sound could have been heard – it just wasn’t, while the philosophers would contend that since it wasn’t heard by anyone, it wasn’t a sound.
Either way, it doesn’t really get us terribly far, but it does link into the topic of the loudness of a sound, and how it’s measured, which is behind the very concept of acoustic or sound proof doors.
The unit of measurement is the Decibel, originally named in honour of Alexander Graham Bell.
So what was the loudest sound ever …
Before we come to the loudest sound in recorded history – any guesses? – we’ll take a quick look at the scale again.
The Decibel is a logarithmic unit which expresses the ratio between two values of a physical quantity, commonly being power and intensity. Sound intensity follows an inverse square law from the source i.e. doubling the distance from a noise source reduces its intensity by a factor of four. On the scale, the smallest audible sound (near total silence) is set at 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence, however, is 20 dB, and a sound 1,000 times more powerful than near total silence is 30 dB.
To put things into perspective, let’s now look at some examples of common sounds and how many dB they are:
- Near total silence (threshold of normal hearing) – 0 dB
- A whisper at 2 meters – 15 dB
- A normal conversation at 1 meter – 60 dB
- City traffic, from inside the vehicle – 85 dB
- A lawnmower – 90 dB
- A jack-hammer at 20 meters – 95 dB
- A car horn – 110 dB
- A rock concert or a jet engine – 120 dB
- A gunshot or firecracker – 140 dB
- Death of hearing tissue – 180 dB
Any sound above 85 dB can cause hearing loss. Any sound above 140 dB causes immediate damage, and actual pain! No more than 15 minutes at 100 dB without protection is recommended, and NO exposure without protection of more than 110 dB is advised.
If you would like some further information, here are three useful links:
Decibel comparison loudness chart (and other useful links)
Heath and Safety Executive on Noise
The Control of noise at work regulations
In our next article we’ll cover recommended noise levels, how we measure noise reduction, and the soundproofing properties of acoustic doors. But for now we take you back in time to 27th August 1883 and the island of Krakatoa. A volcanic eruption took place that allegedly “caused shock waves 100,000 times more powerful than a hydrogen bomb”. The sound was apparently heard nearly 5,000 km away (to put things into perspective, that’s the distance from London to, say, Lagos in Nigeria). That’s an awfully loud sound – and one example that the philosophers wouldn’t use!
Contact the experts
We can’t promise that our doors will protect you from volcanic eruptions, but we can promise you expert advice.
Please click visit the home page or sound proof doors for more information.Alternatively, call us any time on 020 3199 5845 and we’ll be delighted to pass on our expertise.
