Here at Hush City soundproofing, we are always hunting down new information about acoustics and soundproofing, both for our own research, and to share with you. Along the way we’ve come across some pretty interesting stuff. See our favourites and let us know if there are any sound facts we’ve missed
1. Sound is the term to describe what is heard when sound waves pass through a medium to the ear. All sounds are made by vibrations of molecules through which the sound travels. For instance, when a drum or a cymbal is struck, the object vibrates. These vibrations make air molecules move.
2. Noise can be defined as unwanted sound which produces discomfort on the ears. Noise-induced hearing loss (NIHL) is the only type of hearing loss that is completely preventable. The maximum safe threshold for humans is 80 decibels. For those who work above the limit, in the long run will have a hearing loss. The most common and easiest ways to prevent NIHL in your own home is to sound proof your space, keep noisy machines away from living areas and limit your time spent with prolonged use of noise.
3. Hearing loss caused by noise is due to damage to tiny hair cells in the inner ear. It is irreversible – hence, why you need good soundproofing!
4. Q – Why do our recorded voices sound so weird?
A – Two pathways exist that we hear our voice through when we are talking, he explains. One is the way that we perceive most other sounds, involving waves that travel through the chain of hearing systems to inner, middle and outer ear. But because our vocal chords vibrate when we speak, the second path is internal, conducting sound vibrations through our bones directly to our ears.
5. The Big Bang was noiseless. Everything in the universe expanded uniformly, so nothing came into contact with anything else. No contact, no sound waves.
6. For a really big bang, you should have heard Krakatoa in 1883. On Aug. 27, the volcanic island in Indonesia erupted with the explosive power of 200 megatons of TNT. The eruption could be heard nearly 3,000 miles away, making it the loudest noise in recorded history.
7. Loud airguns used to locate gas and oil under the ocean floor are causing animals to leave their natural habitats.
8. This year, Environment Minister Anil Madhav Dave said that noise pollution exceeds allowable limits in seven cities in India, including Mumbai and Delhi.
9. Electric vehicles are so quiet they’re a danger to pedestrians; such cars are now required to have devices that artificially generate sound to indicate their approach.
10. White Noise has long been thought to help sleep, but scientists recently discovered that ‘Pink Noise’, a mix of high & low frequency sounds, is more effective.
11. Psychoacoustics is the study of how sound is perceived and how it affects the body and mind.
12. Sounds louder than 85 dB can damage your hearing. Again, why quality soundproofing is important!
13. Dogs can hear sound at a higher frequency than humans, allowing them to hear noises that we can’t. Just imagine the soundproofing they would need!
14. Blue whales are the loudest animals – their whale calls are a whopping 188 decibels (dB)! Jets, by comparison are 140 dB.
15. Jets get a bad rap. According to psychoacoustician Hugo Fastl, people perceive airplane noise as if it were 10 dB greater than the equivalent noise made by a train. Since the decibel scale is logarithmic, growing exponentially, that means a jet sounds twice as loud as a train when the noise levels of both vehicles are objectively the same.
16. Poor acoustics and long reverberation times can cause glass rooms to become unusable due to speech unintelligibly.
17. The noise you create by cracking a whip occurs because the tip is moving so fast it breaks the speed of sound!
18. Sound travels faster through hard materials like wood than it does through air – 8,859 miles per hour (mph) versus 767 mph. Vibrational noise through a building structure – not airborne – is what causes many soundproofing issues.
19. A Sound level meter, or decibel meter is used to take a reading of the noise level at any given moment. A Noise Dosimeter is used to measure the average noise exposure during a given period of time, such as an eight-hour workday. This helps determine whether the cumulative amount of noise that a person is exposed to is hazardous. An Audiometer is used to test a person’s hearing, to identify and quantify any hearing loss. It can be a precision instrument, as used in clinics and occupational settings, or a home audiometer device or PC software program for basic screening. Results of audiometric testing are plotted on a chart called an audiogram.
20. The first known noise ordinance was passed by the Greek province of Sybaris in the sixth century B.C. Tinsmiths and roosters were required to live outside the town limits.
21. Recognizing noise exposure as an occupational safety hazard took longer. The first scientific study was initiated in 1886 by Glasgow surgeon Thomas Barr. After he tested the hearing of 100 boilermakers, he determined that incessant pounding of hammers against metal boilers caused severe hearing loss.
22. You can fight noise with noise. The first patent on “active noise cancellation” dates to 1933, when German physicist Paul Lueg proposed to silence sound waves by simultaneously generating waves of the exact opposite orientation. The principle is now used in noise-canceling headphones.
23. And people are only getting louder. According to the World Forum for Acoustic Ecology, the volume of an animated conversation between Americans increased by 10 dB during the ’90s.
24. Back in the ’60s, Bell Labs astronomers Arno Penzias and Robert Wilson kept picking up static with their radio telescope. They eventually realized that the noise was the sound of the universe itself, a remnant of a dense, hot plasma that pervaded the early cosmos.
25. At least 15% of adults have permanent hearing damage due to noise exposure. In 2005-2006, 20% of US adolescents 12 to 19 years old had some degree of hearing loss. This is up from 15% as measured in 1988-1994.
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Stats and figures courtesy of Wikipedia and various websites