I love active noise cancellation
Tablets are perfect for commuting. Compared to a laptop they are much smaller and easier to fit in a cramped seat, and compared to media players they’re more versatile and aren’t limited to media only. One of the few places I’ve actually seen tablets in the wild is on the train, and when I’m on the train to visit family later today my iPad will be with me. And so will my active noise canceling headphones.
To understand how active noise cancellation works, some basic physics courses is a big advantage. At least they covered waves when I had such a course, and that understanding formed the basis for grasping how this technology works. Sound is simply waves, and they behave like other waves- those on water, for instance. Similar waves can be amplified or canceled by other waves, all depending on their phase.
When this theory is applied to audio technology, you get active noise cancellation. Headphones with this technology have microphones on both headphone cup (or IEM) which collects noise from the surrounding area. This sound is then inverted and fed into your ears along with the audio from your device. The outside noise that penetrates the passive noise isolation of your headphones will then be met by an inverted version of itself, and the two cancel each other out. The result is that a significant (but not perfect) amount of outside noise is “magically” removed by putting on a pair of headphones with this technology built in.
The alternative to active noise cancellation is passive noise isolation. IEMs (In-Ear Monitors, earphones that go deep) normally isolate very well on their own and many people prefer this over the much more complicated active NC system. Personal preference is really all it comes down to here, as both system have their pros and cons. Active NC requires batteries, complicated electronics in the headphones (or the device, with special headphones with mics going to it, like some Sony MP3 players) and they’re more expensive. They can also creep people out and cause headaches to some people, as the silence created by active NC can sound a bit unnatural. On the other hand though, active NC has some neat advantages as well. Not everyone likes IEMs, me included. I don’t find them very comfortable, and gives me the feeling of sitting in the corner with my hands over my ears going “nanananana can’t hear you”. It blocks the noise, but the noise is still there, and if you’re wearing them with no audio coming from your device then you get the ocean-effect from blocking your ears. Active NC headphones can even be open, meaning they don’t block any sound by themselves- which means they don’t give you the closed-in feeling. The active NC feature will make up for the lack of noise isolation with noise cancellation, so you can still wear comfortable headphones in noisy places.
The noise cancellation works best with steady background noises, rather than detailed speech etc. I use my Bose Quietcomfort 3 headphones at home a lot because it completely removes all the background noises that are present when living in a city; the fans on your computers, some far away air system going, passing traffic etc. It leaves you with a silence that you can only find in the middle of nowhere, far away from both computers and other people. I also use them a lot with audio actually going through them, normally on the train and bus. They will then remove a lot of the engine noise and more general background noise, though nearby, clear speech (you know, the bozos who think train rides are perfect for taking loud calls) are only reduced a bit.
The active NC headphones have basically become standard issue with my iPad when commuting, because the combo works so well together.It lets me do whatever I’m doing without getting annoyed by everyone else’s personal sounds. Last time I was on the train there was a woman a couple of seats away from me who talked to herself the entire way. I tried to spot a Bluetooth headset, or a very tiny person beside her in what was indeed an empty seat (she was looking at it and waving as if explaining something to an invisible person), but it all became clear when she (alone, there were no other person, on the phone or otherwise) went off the train at the same station as me and immediately started searching the closest garbage can for empty bottles (which you get money for in Norway as part of a recycling effort) while still talking and waving about. That is exactly the sort of people I do not want to overhear on a train!
I wouldn’t really recommend the Bose Quietcomfort 3s themselves though, even though I love mine. They work well, are comfortable and rather small, but they’re very overpriced. Sennheiser has a lot of nice options though that are much cheaper, but I can’t comment on how well the noise cancellation works on those. Again, this type of headphone is best suited for those who don’t really like IEMs, because they do much of the same thing but in a way that doesn’t required plugging up your ears. Since most people who travel with their tablet also brings headphones, it’s well worth to check out this type of headphone if the anti-IEM description fits you.