In the spirit of the holiday season, I was browsing those great Cyber Monday deals the weekend of Black Friday and came across a great looking pair of fancy "noise-cancelling" headphones.
http://www.amazon.com/Bose-QuietComfort-Acoustic-Cancelling-Headphones/dp/B00M1NEUA0/ref=sr_1_1?ie=UTF8&qid=1449696020&sr=8-1-spons&keywords=noise+cancelling+headphones&psc=1
I've tried noise-cancellation before at various stores and can attest to their effectiveness. However, how does this technology work? You can't just swat sound waves out of the air. Turns out, you actually use sound's nature as a wave against them!
Let me ask you a simple question: What is sinΘ - sinΘ ? You don't need to know trigonometry or calculus to know that anything minus itself is zero. When talking about noise cancellation, that zero means a quiet listening experience!
Waves can be mathematically represented using sine or cosine, and when two waves meet, the result is their sum. Say that one wave can be represented with sinΘ and another wave is represented by
-sinΘ. When they meet, the result is sinΘ + (-sinΘ) = 0. This process, called complete destructive interference, results in both waves cancelling each other out and a heightened enjoyment of the sounds you actually want to hear!
Sources:
Harris, William. "How Noise-canceling Headphones Work." HowStuffWorks. N.p., 14 Feb. 2007. Web. 10 Dec. 2015.
Waves can be mathematically represented using sine or cosine, and when two waves meet, the result is their sum. Say that one wave can be represented with sinΘ and another wave is represented by
-sinΘ. When they meet, the result is sinΘ + (-sinΘ) = 0. This process, called complete destructive interference, results in both waves cancelling each other out and a heightened enjoyment of the sounds you actually want to hear!
Sources:
Harris, William. "How Noise-canceling Headphones Work." HowStuffWorks. N.p., 14 Feb. 2007. Web. 10 Dec. 2015.
I've heard of those "noise canceling" headphones but I never thought that they actually worked. Its pretty cool how the waves cancel each other out. I think I'm going to go buy some for myself.
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