The PXC 250 NoiseGards are noise-cancelling headphones that cut away steady, low-frequency background noise. We tried them in a variety of challenging test sites, the most dramatic of which was standing next to a whining extractor fan in a busy kitchen. With a flick of the NoiseGard's On switch, the fan's whirring was cut to near zero.

Back in the office, equipment like photocopiers and annoying air-conditioners were silenced, too. When random noises happen, such as talking, the sound still comes through, but the general orchestra of humming machinery dies away.

For long haul travellers these headphones could really come in handy. Imagine being able to sleep in silence without the droning sound of the turbines. Sennheiser is gunning for this type of business traveller. The PXC 250s are lightweight enough to make good travelling companions, and foldable, while a 3.5mm double mono jack (of the type needed in a plane) comes in the box.

Closed ear cups can be bulky to wear compared to their in-ears cousins, but after six hours of near continual use we experienced no noticeable ear fatigue. That said, you wouldn't want to go jogging with them; the soft, silky ear cushions aren't exactly sweat friendly, and the NoiseGard box embedded into the cabling is bulky. But the size and weight of the tube-shaped NoiseGard box, especially when loaded with its two AAA-sized batteries (not included), is the only major drawback of the PXC 250s. Knocks to it can be heard through the ear cups as feedback, so movement is out.

When stationary, these problems cease to be an issue; the cabling is 1.8 m long, which is easily enough to let the box sit still on a table or in a pocket.

Aside from the noise cancelling, the sound quality is excellent with clear warm bass and mid-range, and detailed but not overly bright treble. We had muffled sound when we hooked up the input jack to an old record player, but doubt that will be an issue for most people. James Ellerbeck