The Naim HDX is a hard disk player. It's not a hard disk server.

That distinction isn't mere semantics; it's Naim encouraging potential customers to view this new-generation machine as a stand-alone, high-class hi-fi component, which is what it's primarily designed to be.

The HDX is intended to sit alongside the other sources in your hi-fi system rather than skulk under the stairs or hide in a cupboard with the rest of the gadgetry in a distributed audio set-up. And it's quite capable of handling all that custom-installation malarkey, but if that's what you're after, there's a range of NaimNet HD servers specifically designed for that purpose.

Audiophile's paradise

No, the HDX is aimed squarely at the audiophile – it's even performance-upgradeable through the addition of external power supplies.

We tried it solo and with the £2,750 XPS2; if you've been financially blessed, the £4,750 555PS is doubtless the top option, although that's just an educated guess, as we weren't fortunate enough to have one to try.

Don't fret if you can't afford a power supply straight away, though – the HDX starts life more than adequately powered, as do most Naim electronics. That said, the sonic and musical differences the XPS2 makes are instantly appreciable and once you've heard them, you won't feel inclined to do without!

Effective CD-ripping

In addition to offering thoroughly modern convenience features, the HDX is a no-holds-barred example of Naim's traditional, 'God is in the detail' audiophilia.

The prime manifestation of this is the CD-ripping 'engine', the mix of mechanics and software used to create bit-perfect copies of the CDs fed into the front-panel drawer.

Rather than rely on the widespread 'burst mode' ripping technology, which is prone to introducing and perpetuating errors, the Naim ripper works more methodically, reads discs multiple times and uses no caching to ensure you get replay that's free from inaccuracies or time offsets.

Easy to operate

There are several ultra-convenient ways to operate this hard-core player. You can control it via its front-panel touchscreen, or using the supplied remote control with the display's output appearing on a TV.

You can just as easily access it through a PC on the same network, or with a device such as a Nokia N800 Web tablet. Those with 20/20 vision could even use a Flash-enabled Web browser on a suitably flash mobile phone.

Music ripped onto the HDX winds up on a specially selected Seagate hard disk and every night it's automatically backed up to a similar internal drive.

If you need more storage than the 400GB provided it's possible to add external disks in the form of USB drives or NAS (Network Attached Storage, which should also be frequently backed up for security) and, of course, the player can read shared files on any computer that's attached to the same network.

Although the HDX will play a variety of file types, including WAV, FLAC and MP3, it only rips in uncompressed WAV format. As a result, its drive will accommodate about 600 CDs.

Transferring your files

Feeding the HDX with new material is about the only boring aspect of using it; you could say the same, however, of any player or server with similar capacity.

We used an NAS (network-attached storage) device from Linksys and USB drives from Western Digital and Seagate. While the HDX is near silent in operation, that wasn't always true of the Linksys, which we parked in our listening room, but could, of course, be situated anywhere within reach of your network cabling.

One word of warning here, though: don't scrimp on the drives you use in your NAS or USB boxes. Many data drives that function well in a normal PC environment perform poorly when asked to stream data, so, where possible, buy drives recommended for their streaming capabilities, such as the Seagate DB35 models. Naim will shortly release a list of recommended devices that have been proven to work well with the player.

We listened to the HDX mostly with an XPS2 power supply through a Naim NAP 250 tri-amp system driving active Naim DBL speakers, with the player and the CDS CD player connected to the NAC52 preamplifier with identical Chord Company Indigo DIN-to-DIN cables.

We also used a smaller passive system featuring a Naim Supernait and Neat Petite speakers on Partington Super Dreadnought stands.

Sound quality

The first thing you notice with the HDX is the ease with which you can listen to it. The sound has none of the ragged edge or fragility you occasionally still experience even with high-quality CD players.

This isn't to say the HDX sounds overly smooth or too polished. In fact, it does a fine job of sympathetically handling music that has a genuine raw edge. Its sound simply exhibits a sense of composure and unflappability, even when the music becomes utterly frantic.

Rodrigo y Gabriela's guitar playing on their self-titled album serves to demonstrate the superb control of the HDX alongside its musicality; it drags every scrap of detail and nuance from the recording, and replays it with a beautiful sense of flow, fluency and dynamics. And those dynamics are impressive for their precise gradation.

Dynamic performance

Too many listeners imagine dynamics as a one-way street, wherein quiet sounds suddenly become louder. The HDX capably shows that they function just as effectively in the opposite direction, with louder sounds diminishing in volume.

The dynamic gradation effectively differentiates the two guitars here, along with the two players and their different but complementary styles.

Furthermore, this dynamic acuity, along with the player's faithful recreation of note shape, adds chiaroscuro and genuine texture to the music. This is particularly noticeable when Gabriela slaps the soundboard of her guitar and the full woody resonance – rather than just a dull, anonymous thud – emerges.

The sheer vibrancy of the sound of the two instruments lends real excitement to the music – even to the duo's recreation of that stodgy old warhorse Stairway to Heaven.

Extra power

Earlier we mentioned the benefits of adding an external power supply to the HDX. It's important to recognise that this doesn't bring about rudimentary improvements: it isn't a case of the player not doing something or doing anything wrongly without the power supply.

The addition of the XPS2 or, we expect, the 555PS, simply enhances what's already present – instruments and vocalists gain a greater sense of body and presence and the most minute nuances surface readily from the depths of a mix to garnish the proceedings.

Alongside such hi-fi considerations, the HDX turns in an equally remarkable musical performance, which we assessed by simultaneously listening to a Dr Feelgood CD and a rip of the same disc that we'd stored on the player's hard drive.

Refined sound

The CD player used, a Naim CDS, is no slouch, and its performance, while spirited, is certainly not edgy – so it came as a surprise that the HDX/XPS2 managed to surpass it in several important respects. In comparison with the CDS, its dynamic contrast – in particular the way notes finish – lends its timing a sharper edge and provides a keener sense of space around the notes.

At the same time, its sound has a more refined quality that's especially noticeable with hi-hat, which sounds, well, more like a hi-hat – you can hear the rush of air escaping as the hi-hat closes and the change in timbre when the two cymbal elements come together.

Hi-hats can often sound disappointingly insubstantial, but that isn't the case here. It might only be a small consideration, but the difference in presentation is distinct and greatly increases the realism of the performance.

Intoxicating experience

The greater sense of space also means that fast guitar lines are rendered with greater flow and clarity. Instead of them merging into a blurred flurry of notes, you can hear a clear melodic progression even on the speediest of arpeggios or sweep-picked phrases.

Perhaps, though, the composure and expressive abilities of the HDX – particularly when powered by the XPS2 – are most forcibly demonstrated with classical music, which is frequently rendered in such a captivating manner that even avid rock-music devotees will be keen to listen to it.

We played both high-definition (96kHz/24-bit) and standard (44.1kHz/16-bit) recordings and each of them was portrayed with palpable instrumental timbre and within a credible acoustic environment. You can not only sense the reverberant qualities of the surroundings, but virtually pinpoint the position of the recording microphones.

Ultimately, however, what emerges isn't just more detail or more timbre, but more music. The voices of the choir and soloists on Berlioz's oratorio L'Enfance du Christ exhibit a naturalness and fluency that's completely intoxicating, while the orchestra and leader on Dvorák's Violin Concerto, particularly in the Allegro ma non troppo, mix awe-inspiring weight with a delicacy of touch that delights as it reveals ever more about the performance quality.

Naim impresses

We would argue, however, that the true measure of any hi-fi component's worth is whether you can read, write or truly concentrate on anything else while that component is playing. With the HDX, the answer to that question is a resounding no.

We didn't expect to be won over by a computerised box of tricks, but we have. Now, it would seem, our rooms need no longer be littered with CDs. After all, who, apart perhaps from CD555 owners, really needs a CD player any more?