In the olden days we had Hafler surround by simply connecting up a pair of 'rear' speakers a bit oddly. Then the Dolby people created a home cinema revolution, courtesy of their licensed surround technologies and a little piece of magic called Pro Logic (hands up who was into AV back then?).

Quite early on in the process, Lucasfilm got involved in creating a book of standards that, if adhered to by license, along with some clever post-processing, would result in a sound and vision experience that Uncle George figured his and everybody's audience truly deserved. THX was its name; a standard for building speakers, amps, and whole professional cinema auditoria - right down to the degree of reflective surfaces and sound-absorbing drapes. In the Empire Cinema at Leicester Square, they used to screen a THX demo sequence involving jumping audio tracks and a laser light show. The audience would burst into spontaneous applause before the movie had even begun!

The rest is history, with Dolby's five surround speakers and single subwoofer supporting the 5.1 format and becoming the de-facto standard for DVD, with DTS as a secondary player.

THX's fortunes have ebbed and flowed, particularly outside its native USA. Not everyone needed the original specification of Home THX and a secondary THX standard evolved. Thus we got Ultra for larger rooms, and Select for smaller ones. Theories and electronics were largely the same, except for overall power and sound pressure ratings.

As the quality and frequency range, or passband, of movies' soundtracks subsequently went through the roof, another, newer set of standards was called for, again in two sets of orderof- magnitude arrays, now to be called THX Ultra 2 and Select 2.

Which brings us to this: the system that was used at the press launch of Revenge of the Sith, as set up by the Jamo importer's Mr THX, Mark Cheffins. What he doesn't know about THX ain't worth knowing.

So what comprises THX speakers these days? Well, you are looking at a 7.2 system: two large 15in equipped subwoofers; five directradiating surround sound satellite speakers for rears and front use; and a brace of superb dipolar side speakers with rakes of drivers in them all.

Speakers corner

Although undeniably large, by usual THX speaker sizes these can claim almost claim to be petite. Some lunatics might even consider wall-mounting the main L/C/Rs, such is their limited depth. In point of fact, that is how they have been designed and it's in that configuration that they earn their THX stripes. But to be honest, stand-mounting them close to a wall boundary is for me the more acceptable option.

The D 7LCR (which stands for left, centre, right) are letterbox rather than tower style and have a pair of jumperconnected sets of binding posts on their rears. They come with rubber stand studs, and a set of wall-bracket mounts that are no more than steel receptacles (with pre-drilled locations) for a wall screw fixing to marry up to. On each side of the box you get a serious looking golfball dimpled 5.5in cone for bass, with a vertical array of small speaker drivers between them. These comprise an annular ring tweeter and two stiff but well-suspended 2.5in mid-range jobs.

The surround enclosure (D 7SUR) has two sets of these sexy small drivers, arranged vertically but at 45º angles to the ends of the boxes, mounted such that when on a wall alongside your seated position, they create a perfect dipolar surround pattern. The central part of the box houses one of the 5.5in bass units.

The D 7SUB subwoofer is a simple gut-bucket of bass. A mighty 15incher lives in the face of each one - you get two with the full-on Ultra 2 specification, each one with a meaty half kilowatt of grunt, which can reach down to 20Hz (required by the specification). Each of the seven surrounding boxes - three across the front, dipolar sides and two regular rears - came with a solid-feeling stand, that adds £300 a pop to the system for each one..

In use, these speakers are a hardcore movie fan's dream. Dynamic, exciting and totally involving. Partner them with a grand's worth of THX-certified amplification and you're away.

So good is the experience, that I wanted to revisit my entire DVD collection. A great test disc for these babies turned out to be the THXremastered Aliens.

Early on, Ripley asks how long she was in stasis before the salvage team found her. She suddenly spasms, knocks a glass of water onto the floor and her chest bursts. Then she wakes up... The sound of the glass's destruction happens stage front and centre and the dynamic rise lifted me clean out of my seat (no easy feat!). Further on, we see the alien-ravaged colony of Hadley's Hope (population 150). A huge truck is arriving at the atmosphere processor. The sound is massive, deep rich and throbulent. I found out certain things were being shaken off shelves. Marvellous.

The front soundstage is detailed and warm. There's not a harsh bone it this cabinetry. By their nature these speakers are very directional, so positioning and toeing in, is crucial.

With CDs the system has less sparkle; this is definitely a cinephile system first and foremost. If you do want to use the system for music, I'd advise that you try and ensure your electronics have been configured for THX music mode.

The output of this handsome system is Brobdingnagian - seriously pro style for domestic use. They certainly sound better than my local cinema system; it's large and lovely to be pinned to the sofa by. However, the D 7PEX isn't for dilettantes. This system is reference grade, state-of-the-art, cinematic joy. I loved them.