Like HowStuffWorks on Facebook!

How Noise-canceling Headphones Work


How Noise-canceling Headphones Work: Author's Note

At some point in his or her academic career, a student learns the difference between pure and applied science. Here's the classic definition: Pure science is a method of investigating nature by the experimental method, while applied science is the application of pure science to some practical human purpose. This was an interesting article because it embodied the very essence of applied science. The pure science involves the structure and function of sound waves. The applied science involves how to take that fundamental knowledge and use it to solve a specific problem -- in this case, blocking unwanted noise.

Bose, of course, is a pioneer in developing innovative audio systems. In many ways, Bose could be described as a company dedicated to the pursuit of applied science. Amar Bose, an MIT scientist, founded the company in 1964, taking observational data about sound -- and people's perceptions of sound -- and turning it into useful products. The first of these products was the 901 Direct/Reflecting speaker system, released in 1968. Noise-canceling headphones came later, but they evolved in a similar way, moving from the laboratory bench to the retailer shelf. In fact, as the article explains, Amar Bose first conceived of noise-canceling headphones while on a noisy commercial flight. That image -- of a classically trained scientist trying to solve an everyday problem, scribbling his thoughts on a cocktail napkin at 35,000 feet (10,668 meters) -- stayed with me throughout my work on this article.

Sources

  • Bose Learning Center http://www.bose.com/controller?event=VIEW_STATIC_PAGE_EVENT &url=/learning/index.jsp
  • Dennis, Johnnie T. "The Complete Idiot's Guide to Physics." Indianapolis: Alpha Books, 2003.
  • Gundersen, P. Erik. "The Handy Physics Answer Book". Canton, MI: Visible Ink Press, 2003.
  • Holt, J. Gordon. "Audio basics: A is for ampere," Stereophile. March 1991. http://stereophile.com/reference/62/
  • Encyclopedia Britannica 2005, s.v. "headphone." CD-ROM, 2005.
  • Encyclopedia Britannica 2005, s.v. "noise." CD-ROM, 2005.
  • Fischetti, M. "Reducing a roar," Scientific American. Exclusive online issue. October 2006. http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssuePreview &ARTICLEID_CHAR=4A46FA21-2B35-221B-6561015527D8F570
  • "A quick guide to headphones." HeadWize. http://www.headwize.com/articles/hguide_art.htm
  • Sems, Marty. "How noise-canceling headphones work," Smart Computing. January 2004. Volume 15, Issue 1.

More to Explore