What Noise Cancelling Actually Cancels

It is built for steady, low droning sound, and that is where it is close to miraculous. Aircraft cabin noise, a train, a bus engine, the hum of air conditioning in an office — these are constant low-frequency sounds, and cancellation works by generating the opposite waveform, which only works reliably when the sound is predictable. For a long flight it transforms the journey.

It is far weaker against voices, and that is worth knowing before you buy. Speech is irregular and higher in pitch, so a colleague talking or a child crying comes through much more than the marketing implies. Anyone buying this to escape people rather than engines will be disappointed by cancellation and helped mostly by the physical seal of the earcups.

Transparency mode solves the problem cancellation creates. Sealed headphones make you unable to hear a station announcement, a colleague or traffic; a transparency setting pipes the outside back in without taking them off. For anyone walking near roads it is a genuine safety feature rather than a convenience.

• A brother with a long commute by train, bus or plane
• Someone in an open-plan office or a shared house who needs to concentrate
• A student working in noisy places
• Anyone who flies home regularly — long-haul is where these earn their keep

• Transforms specifically the long journeys people dread
• Over-ear fit stays comfortable for hours in a way earbuds do not
• Used almost daily by anyone who commutes

The things worth checking before you order — this is where gifts like this most often go wrong.

• Battery figures are usually quoted with cancellation switched off. A headline playtime number is the best case; expect meaningfully less with cancellation running, which is how they will actually be used.
• Over-ear is the right choice for long sessions and the wrong one for the gym. They are warm, they are bulky in a bag, and they are not what anyone wants while running — if he trains rather than commutes, this is the wrong shape of product.
• Some people get a pressure sensation from active cancellation, occasionally described as ear discomfort on the first few uses. It is common, it usually passes, and it is worth knowing it is not a fault.
• Check what the case and cable situation is. A folding design without a case gets crushed in a bag, and headphones that cannot also run on a wire are useless on the aircraft entertainment systems that still use a socket.