Sporting a slim, purple aesthetic like their last few NW series Walkmans, Sony's latest digital music player, the NW-S705F, claims an interesting niche in the MP3 player market. Its bass-heavy sound is driven by a pair of IEM (in-ear monitor) headphones, complete with active noise cancelling, making this device a great choice for easy listening in noisy environments.

The included headphones provide excellent sound - better than that produced by the vast majority of stock headphones. They are extremely bass heavy, but that matches the overall sound of the player (which we also tested with third party earbuds). The low registers have a lot of power and the bass is quite slow, reverberating for a long time before dissipating. The mid and treble ranges are somewhat overshadowed, but they still have good clarity and a reasonable amount of detail. We didn't find the NW-S705F's sound suitable for all types of music, but bass fans will love it.

The other main feature of the IEMs is their dual noise-cancelling technologies. The first technology is the headphones themselves which, when inserted properly, form a seal around the ear canal effectively blocking out unwanted noise. The second technology is active noise-cancelling. The outer casing of the headphones has vents to allow the internal microphones to pick up ambient noise and cancel it by creating an opposing sound wave. We found this noise-cancelling combination extremely effective, and we'd highly recommend this unit if background noise irritates you.

The actual IEMs themselves are rubber tipped and quite comfortable. The unit comes with two different sized tips but unfortunately does not come with any foam alternatives which we usually find better at creating a seal. Thankfully, the stock ones were more than adequate in this regard and were comfortable for long listening sessions.

The active noise-cancelling function can be turned on and off in the menu - turning it off had no negative effects on the sound quality. Other menu options include the standard array of shuffle and repeat modes, as well as playlists and a five-band equaliser with both preset and custom modes. The equaliser settings have a reasonable impact, and are a good way to help compensate for the dominant bass.

Aesthetically the unit is attractive. It follows a very similar theme to Sony's previous Walkman efforts, with a slim, purple design and a hidden screen. The display is hidden behind the mirrored facade only appearing on the face of the unit when displaying information. This adds a sleek, minimalist touch to the design, and complements the style of the unit.

Another cool feature of the display is the fact that, despite being rather tiny, it can display album cover art, as long as it is uploaded with your music. Being a Sony product, NW-S705F users are once again relegated to using SonicStage to upload music onto the device. This is one of the key problems with the unit, as SonicStage can be a nightmare to use. It isn't as intuitive as something like iTunes (which can be annoying itself), and is a lot more hassle than a simple drag and drop interface.

Continuing the minimalist aesthetic, the controls are well disguised. On the front there are play/pause and volume controls, while track skip and menu navigation are handled by a jog dial on the end of the unit. There are also several other buttons, including a menu key on the side, and both a hold switch and mode button on the back of the unit. The interface is a little confusing at times, because of the somewhat haphazard placement of controls, but with a little practice it becomes easier to use.

The unit supports a variety of formats, including MP3, WMA, AAC and Sony's proprietary ATRAC. It also has an FM radio, which worked well throughout our testing.