Over the last couple of years, Sony has perfected the art of adding in extra features for their users. Features that the Xperia Z line has now become known for, and unlike other manufactures, these extra features are also worked in to the overall experience thoughtfully and there for when users need or want them. With the introduction of the Xperia Z2 and the Xperia Z2 Tablet, Sony introduced a hardware addition to the overall experience, in the form of the MDR-NC31EM earbuds. As always, a lovely name from Sony, but all we really need to know about these guys is that they're a noise cancelling set of earbuds. They were launched to work (to their fullest at least) with the Xperia Z2 and the Xperia Z2 Tablet, but they'll also work just fine with the new Xperia Z3, Z3 Compact and the new Z3 Tablet Compact. While they don't feature any mic or noise cancelling features on anything other than Xperia devices, you still get full stereo from your laptop or other devices though, so it's not too awful
The NC31EM set are available in either black or white and they feature a short left earbud cable and a longer cable for the right earbud, which goes around the back of your neck nice and neatly. This is nice and I really wish more earbud manufactures would do things this way. So, how does the noise cancellation work? Well, it uses the Xperia Z2, Z3 or whichever compatible device to do the magic work that a box powered by a single battery might do and there are microphones on each of the two earbuds that record the noise your phone or tablet cancels out. These microphones also work for calls when used with an Xperia Z device.
As for music listening, these sound really quite nice. They have a slightly warm tone to them, but they're not muddy by any means and they're fairly crisp. They're not quite as crisp or clear as a pair of Bose in-ear 'phones but then they're not priced as such, either. They have a frequency response of 20 Hz to 20,000 Hz and they produced some good bass while I listened to Metallica, some Iggy Azalea and everything in between. For fans of rock music, I can tell you these really do the job and I've been listening to some Electro-Pop lately like CHVRCHES and it all sounds great.
With Sony's software on the Xperia Z devices, you can adjust the environment you're in, which adjusts how severe the noise cancellation is. There are three modes, 'Office', 'Bus/Train' and 'Airplane'. While working away at home, the Office setting cuts out all keyboard noise from the Chromebook and almost silences my Razer Blackwidow Ultimate mechanical keyboard, which is impressive as that thing is loud. I tested these out recently on a train while listening to some Podcasts and I couldn't hear a thing apart from my podcast. As a bonus, the Xperia Z2 and Z3 line feature a nice and simple equalizer that allows you to push these guys to whichever type of music you want to listen to, and I never noticed any extra battery drain compared to 'regular' earphones or headphones.
As far as comfort goes, these are a middling pair of earbuds. They're far from uncomfortable, but after a few hours my ears did start to hurt, but then again this could be because I have the bass slider fairly up there. I would have liked a smaller size of earbuds in the box, but the smallest pair aren't painful, and despite the buds' size they haven't popped out of my ear once. I'm confident that they're built to a pretty decent standard and my only real complaint is that there's no button to play/pause music or answer calls, this is an oversight on Sony's part I feel, but then again I guess Sony did have to compromise on something, at least. Overall, these are an excellent pair of earbuds for the money and the noise cancellation really works to a proficient standard without the need for a box dangling around your neck. They're available from Amazon using the links below and if you're lucky to get these included in your Xperia purchase, then you should definitely pay more attention to these than other throw-ins. My Z2 didn't have these in the box, instead I was given the charging dock, but these are definitely worth the extra purchase in my eyes.