Noise Cancelling Headphones
One of the problems that headphones should in theory solve is that of excessive noise. If you are listening to music in a busy room or outside in your car for example, your music has to compete with lots of other background noises before it makes it to your eardrum. Headphones place the music right next to your ears, meaning that most of the noise should be blocked out. However this is rarely the case, and background noise can really spoil good music from even a good pair of headphones. Which is where noise cancelling headphones come in.
Most all headphones cancel out noise in their own way simply down to their shape and positioning around the ear. By their very nature, they make it hard for other noises to penetrate the eardrum effectively. This is known as 'passive' noise cancelling, as the headphone is stopping noise naturally without actually 'doing' anything. However, more expensive, specialist noise cancelling headphones are active in their methods to remove external noise. They do this in a very understated, but actually quite technically advanced method. Noise cancelling headphones have a tiny microphone built in that the user is unlikely to ever know about. This microphone listens to external noise, analyses it, and then uses a speaker in the headphones to transmit it's own noise that will cancel out the incoming noise. This external noise is out of phase with the incoming noise by 180 degrees, meaning it perfectly cancels out most all external noise. It makes them great for car, bus or plane journeys of for people who spend a lot of time in city hotels or commuting; anywhere where you are likely to come up against a lot of background noise when you try to listen to music. Noise cancelling headphones also make you less tired, as over exposure to dull, low level noise can give you a feeling of fatigue or drowsiness.
Your noise cancelling headphones should ideally be from a well known brand, as quality will be proportionate to how much you are willing to spend in a similar way to wireless headphones. The technology has been around for a few years now and is becoming much more widespread but it would still be recommended that you test and trial any headphones before you buy them, including wireless headphones.