Sony is introducing what it's claiming are the world's first digital noise-cancelling headphones, the MDR-NC500D.

The bold boast from Sony is that the new MDR-NC500D cuts out an amazing 99% of ambient noise - although this claim is asterisked and the footnote reads "based on Sony measurement standards".

Apparently, unlike conventional noise cancelling headphones, the MDR-NC500D are the first ever headphones to use digital technology with "Artificial Intelligence".

A processor inside the MDR-NC500D automatically adapts the cancellation profile to suit the characteristics of ambient noise.

In normal use, pushing the "AI Mode" button makes the headphones select automatically from three cancellation modes to suit the surroundings – whether on an aircraft, a bus or train, or in the office, although this can also be manually selected.

A monitor switch is provided for temporary listening to external sounds like cabin announcements and the headphones offer 15 hours operation between charges of the lithium ion battery.

Also new from Sony, the MDR-NC40 offers noise cancelling performance but in a light, space-saving folding design ideal for travellers and commuters.

Complete with protective travel case, apparently the headphones are available to order now, although a product number search on the Sony Style site did not locate either model.