Background noise is arguably the biggest single problem affecting music on the move. One can simply try to block it, of course, but active electronic noise cancelling looks the most attractive option. So we were more than a little intrigued when Sennheiser offered us a pair of its newest noise-cancellers. There are several reasons for this.

First, we've had some excellent results from Sennheiser's conventional (passive) headphones and second, with a strong background in aviation headsets, the company has proved its capability to deal with high noise-level environments.

Sennheiser sensibly relies on a combination of noise blocking and noise cancelling to achieve good results. The literature for the PXC450 headphones claims up to 32dB blocking and up to 23dB cancelling, but what it doesn't say is that while these certainly don't add up (55dB at any frequency would be impressive indeed) they do complement each other.

There's plenty to recommend this model ergonomically, too. First, it works perfectly well as a passive headphone. Simply slide a little switch and the electronics are bypassed, useful when the battery runs out (a single AAA battery lasts for up to 25 hours) or you're in a quiet environment. And a 'talkthrough' button, easily located by feel on the right earcup, allows comfortable conversation over the (semi-muted) music, with low-frequency noise still blocked, while volume is adjustable on adjacent buttons.

Sound quality

We've yet to hear a closed-back headphone that can match the best open models for neutrality, but this one is certainly one of the closest. It's a little coloured in the midrange, but to such a small extent that one can pretty quickly adapt. The drive units also have a very high level of resolution which makes the sound all the more appealing.

In fact, we have to agree with Sennheiser that this is a model which, in passive mode, works superbly when connected to a hi-fi system. Bass is excellent and high treble on a par with models such as Sennheiser's excellent HD650. Detail is a little behind such exalted transducers, but good enough to embarrass loudspeakers up to a few thousand pounds in price.

In the acid test, competing with buses, trains and general 'hubbub' this model really scores. Not only is outside noise reduced, the overall effect is astonishingly natural and you'll be genuinely surprised on removing the PXC450's at just how loud the surroundings are.

Taking into consideration these headphones' intrinsic high quality, as well as all other aspects of their performance, then the PXC450s would definitely be our choice for music on the move.