Top picks: Noise-cancelling headphones

Bringing your music on-the-go with cheap earphones usually means having to live with the ambient sounds around you. If you're in the market today for headphones that cut out external noise, there are those based on noise-cancelling and noise isolation technology. Despite both of them achieving the same results, they operate differently.

In-ear headphones feature noise isolation, which works by sealing up the ear with a variety of foam and silicon ear tips attached to the 'phones. However, for those who are against the thought of putting an object into their ear, there is noise-cancelling technology. It works by producing an audio frequency which cancels out noise.

	1.	Sony MDR-NC500D   Offering a selection of three distinct noise-canceling modes, these can be used in three acoustically different environments: The airplane, bus or inside an office. Sony also claims that the MDC-NC500D is capable of reducing 99 percent of ambient noise with the noise-cancelling feature on. This is also the only headphone in our roundup that features a twin power supply, running on a built-in battery or two AA batteries for up to 28 hours of playback time. % noise reduction: 99 percent Click for larger image
	2.	AKG K 480 NC   The main features on the lightweight AKG offering are its three-dimensional axis-folding ability and detachable single side cable. Having an interchangeable cable also means its compatible with Bluetooth-enabled mobile phones with the optional Bluetooth adapter installed. The downside is that the noise-cancelling circuitry is contained in a separate in-line unit which also houses the AAA batteries. % noise reduction: 70 percent Click for larger image
	3.	Bose QuietComfort 3   The noise cancellation technology works with or without anything played through these head cans. It also features active equalization which adjusts the equalizer according to the type of music played. The unit is powered by a removable rechargeable lithium-ion battery, for up to 25 hours of listening time, and can be made to work with mobile phones with the optional mobile communications kit which includes an in-line mic and adapters to suit different phones. % noise reduction: Not available Click for larger image
	4.	Sennheiser PXC 450   Claiming up to a 90 percent noise reduction, the PXC 450 also features a TalkThrough function which deactivates total noise cancellation and allows the wearer to communicate with other people without hearing background noise. These headphones also feature integrated volume controls and work with or without the noise-cancelling feature on. % noise reduction: 90 percent Click for larger image
	5.	Audio Technica ATH-ANC7b   The ATH-ANC7b offers more comfortable earpads and easier battery access than its predecessor, the ATH-ANC7. Claiming up to 85 percent of noise reduction, it also comes bundled with two choices of cable lengths and will play music regardless of whether the noise-cancelling feature is on or off. Powered by AAA batteries, it provides the listener up to 40 hours of noise-less listening. % noise reduction: 85 percent Click for larger image