"Noise canceling" is simple: Measure a noise frequency,generate noise at the same frequency and with volume timed so that the ups of the generated tone coincide with the downs of the original noise, and you can greatly reduce the net acoustic energy (noise). Canceling white noise in an airplane is easy with earphones-that noise is continuous and predictable, and the canceling speakers are right next to your ears. Lawrence Jerome Fogel obtained five patents for noise-canceling aviation headsets between 1958 and 1961. Bose entered the aviation headset business in 1989 and introduced its first Engine Harmonic Cancellation solution in 2010. Now the company's acoustic experts turn their attention to quelling suspension noise, with an aim toward weight and cost reduction and improved handling dynamics.
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