Sony says that its new MDR-NC500D headphones are the world's first digital noise-cancelling headphones.
They have a built-in processor that activates a special 'artificial intelligence' mode that can modify the sound-cancelling features to cope with the varying levels of background noise found in different environments, such as planes, trains or just an ordinary office. If you need to listen in on whatever is happening around you there's a monitor switch that can let in sound once more. The headphones have a rechargeable battery that lasts for 15 hours, but if they do run down on a long journey they can also run off two AA batteries.
The bad news is that they're going to cost about £269 (US$538). Fortunately, Sony is also releasing a cheaper set of noise-cancelling phones, called the MDR-NC40. Priced at around £79, these are lightweight headphones that can be folded flat and easily slipped into a bag or case.