The irresistible rise of DLP technology shows no signs of letting up. We're about to witness a glut of incoming DLP rear-projection TVs and Thomson's 50in 50DLY645 is one of the most 'mainstream' (ie, affordable) of these DLP newcomers.

Compared to some of Thomson's CRT rear-projection TVs, the 50DLY645's matt grey finish is rather uninspiring. There's the odd dash of panache, with the screen standing proud of the main frame, but overall, blandness wins out.

Connections impress, including three Scarts, component video inputs for high definition and progressive scan sources, a subwoofer line out, plus a video and PC-friendly DVI jack.

The set's interface is superb, thanks to some pretty, sensibly organised onscreen menus. The remote is elegant and attractive, but let down by too-small buttons.

Top of the features is Thomson's Hi-Pix picture processing. Hi-Pix analyses incoming pictures and calculates extra pixels of detail, ultimately delivering around four times more dots per line (although unlike some rival systems, it doesn't add horizontal lines as well).

Hi-Pix also doubles the sampling of the red and blue elements of the YUV colour system during its digitalisation process to deliver allegedly brighter, sharper colours.

Other features of interest include noise reduction, a contrast booster, Virtual Dolby PLII/SRS TruSurround XT audio processing, and a neat picture-in-picture system.

Performance

The 50DLY645 is a decent picture performer, but hardly a world-beater. The first plus you'll notice is its colours. They're exceptionally rich and vibrant, while also achieving a generally natural tone. Part of this success is down to the 50DLY645's more than adequate black-level response, but we suspect Hi-Pix also has its say.

Hi-Pix's detail boosting claims are also justified. Toggling Hi-Pix on and off clearly causes extra sharpness and detail to appear and disappear from the picture. This is actually just as well, as without Hi-Pix the picture can look rather soft.

The 50DLY645's brightness is extremely impressive - especially as it's achieved uniformly across all 50in of the screen, without any 'hotspots'. Our final plus point concerns the way the set almost completely avoids DLP's problems with dotty noise over horizontal motion.

Sadly there's plenty of other noise around, though - especially (though not exclusively) DLP's trademark green dot noise. At its worst, during dark scenes, this can obscure background detail and leave you feeling like you're watching the picture through a fine net curtain.

A curious 'glistening' finish to the picture also contributes to the noisy impression. Other DLP rear-pro TVs, especially Loewe's Articos 55, have shown that neither this glistening nor the green dotty noise have to exist so clearly on a DLP TV.

We also found ourselves more aware of DLP's 'rainbow effect' (where you see bands of pure colour in your peripheral vision) than with other DLP rear-projection sets. Our final niggles concern ghosting and haloing around bright edges, and the set's very limited (by DLP standards) vertical viewing angle.

The 50DLY645 is hugely more consistent with its audio. Its speakers combine a rare bass extension with soundstage width, rich detail presentation and smooth, rounded vocals. They also sound better the louder you ask them to go. Excellent.

The 50DLY645 is rather frustrating, overall. At times its pictures look stunning, but these times are too few and far between for comfort, leaving us feeling that while we await Thomson's next DLP generation with interest, we'll probably give this one a miss. John Archer