Using the Sony DMRXD400 headphones is like a chaotic ride of sound, the bass thumping against your eardrum with exceptional quality, while the design is an intriguing mixture of practicality and science fiction. A few minor flaws disqualify the headphones from perfection, but we think these are fairly minor and forgivable.

The DMRXD400 handle most sound sources without any problems. One of the first things we noticed was the way the headphones block out exterior noise. These are not noise-canceling headphones but when you put them on the world tends to melt away, which is a contributing factor to their ability to envelope the wearer in the music. Our tests found the headphones delivered clear bass without any distortion, but there were a few problems with the treble in the higher registers. String instruments such as violins tended to sound a little muted and at times were difficult to distinguish from the bass line.

Like many closed headphones, the Sony DMR-XD400 concentrate on getting the bass right first, and they do an amazing job in that department. Even though many people value bass above all else, this isn't a reason to ignore the other end of the spectrum. Mid-tones were no problem, with the headphones delivering clear sound preproduction in the mid-range - it was just those higher registers which didn't quite make the grade.

The Sony DMR-XD400 also come with a separate setting to be employed when watching movies. We tested this feature but couldn't see any clear benefit from using it. If anything, setting the headphones to "Movie mode" reduced the quality of the sound, with the bass becoming muddy.

The ear pieces on the Sony DMRXD400 are supported by two coated flexible wire frames which rise from each speaker, meeting at rounded right angles to form a semi-rectangle which sits above the head. From each of these frames, a soft rubber-like plastic band holds the headset in place on the wearer and this is attached to the frame via four spring-loaded rings. When the headphones are worn, the rings move into position to maximise comfort. The cup that encloses each ear is padded and finished with a thin vinyl layer with a foam insert sitting on each of the speakers. We think Sony DMRXD400 are one of the most comfortable HiFi headphones we have used but the vinyl finish does tend to get hot and sweaty after prolonged use.

The Sony DMR-XD400 are an impressive set of headphones which deliver high quality sound preproduction with pleasing aesthetics. The design may not be everyone's tastes as they are quite large and certainly stand out, but a hardcore commitment to audio quality comes with its price.