Wednesday, January 07, 2009

Sony Digital Noise Canceling Headphones

Sony  MDR-NC500D Digital Noise Cancelling HeadphonesThe Sony MDR-NC500D Digital Noise Canceling Headphones use digital signal processing chips to identify the type of noise and then attempt to cancel it out. Reviews are mixed, with Dan Warne saying "The difference was remarkable" (Review: Sony MDR-NC500D, SMH, January 5, 2009) while The Travel Insider said they're not appreciably better than the less expensive Bose Quiet Comfort 2 headphones (Sony MDR-NC500D Digital Noise Canceling Headphones part 1, 26 Dec 2008).

One place where advanced noise reduction is needed is the Emirates A380 crew rest quarters. The engines on the new aircraft are so quiet that the crew have difficulty getting to sleep. Previously the sound of the engines would mask cabin noises, but the Airbus has such quiet engines the crew can hear the passengers outside. Regular electronic headphones would only cancel out the regular drone of the engines making the problem worse.

See also other Noise Cancelling Headphones available from
It should be noted that these headphones are not safety devices and are not designed to protect from dangerous noise levels. There is a separate category of product for that: Electronic Hearing Protection.

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Friday, August 31, 2007

Noise cancelling headphones

Noise cancelling headphonesChoice magazine tested Noise Canceling Headphones, in their August 2007 edition. Surprisingly the more expensive Bose units did not top the list of those recommended. Top was the Jabra C820s, followed by a discontinued Logitech model and then the Bose QuietComfort 2 and Bose QuietComfort 3.

Some years ago I bought a
Panasonic set of Noise Canceling Headphones for using on aircraft. These are very effective for reducing noise, but are uncomfortable on a long flight (such as Sydney to London). These units use active noise reduction, with electronics powered by a AAA battery to create anti-noise. The ear-cups are too small to completely cover my ears. Also the headphones fold into a ball, which is compact, but makes a lump which does not fit in my briefcase. The Jabra and Bose QuietComfort 2 units have larger earcups and fold flat.

Other units are made by companies including: Sennheiser , Philips, IRhythms, Sony, Koss. These include smaller units which designed to sit on the ears and ear buds in the ears, but the larger units which cover the ears completely provide passive, as well as active, noise reduction.

There are also much more expensive units designed for use by the military and pilots, with more sophisticated electronics. In addition there are Electronic Hearing Protection units, designed for protecting against noise which could damage the ears. These units are used by builders and work by blocking sound using passive material and then a microphone to carry sounds at a safe level.

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