Anyone who says LS3/5A-plus-AB1 or WATT-plus-Puppy is gonna get a star: Indigo's Stage One is another grow-with-it scenario of a small two-way monitor with an upgrade path of a dedicated passive add-on woofer system. Not an active sub, not a mono sub, but separate enclosures which, effectively, turn bookshelf/stand speakers into floorstanders.

It starts with Indigo's Model One, a neat two-way which competes in the one-step-above-entry-level arena at £330 per pair. Measuring 10 3/4x8x10 3/4 (HWD), the Model One is a classic, fully-shielded British two-way speaker with a 1in titanium dome tweeter and a 5 1/4in laminated cone woofer with aluminium voice coil. The crossover is 2nd order for the high frequencies and 4th order for the bass, operating at 3.5kHz. It features hard-wiring for all components, is bi-wireable, and comes with gold-plated multi-way binding posts. The enclosure is solid and beautifully-made, with a 1in thick profiled MDF baffle and 3/4in thick MDF side panels, with real wood veneers inside and out. Available as standard in cherry, the Indigos are also produced in black ash and beech; all are fitted with blue-grey grilles which are supposed to suggest the company name. Yeah, right: if you're colour blind, or have a knackered copy of Paint Shop Pro.

Spec'd as delivering a frequency response of 48Hz-20kHz and not too painful a load at 88dB/1W at a nominal 8 ohms, the Model One sounds smooth yet detailed and works well with British solid-state integrateds within its price band; I loved the sound with my now ageing Roksan Caspian, and suspect it will flatter most of the 30-80W integrateds in the sub-£500 bracket. Categorically, these speakers need to be spaced away from walls to 'breathe', so I treated them like stereo monitors rather than A/V products which are normally positioned according to the wife's commands. And while they delivered just the sort of open, airy sound stage I expect of a compact two-way, and the mid-band possessed the requisite warmth, even I had a problem with the lack of weight.

A look at the Indigo catalogue suggests that the company would like to see you using these either as rear channel speakers in a surround set-up, or - as tested here - with the woofer systems to create the Stage One package. Ones-plus-subwoofers sell for exactly £1000, which puts this up against some serious single-piece floor-standing speakers. But the subwoofer sections are rather impressive in themselves, and transform the wee Indigos.

At 26x8x10 3/4, the sub-section creates the perfect stand for the Model 1; I tried the latter solo on a pair of 24in Foundations for the comparison, with extra long spikes to match the height. (I also had to compensate for the extra height added by the pointy cones which Indigo provides for use between the subs and the Model Ones.) Within the enclosure are two 6 3/4in bass drivers fashioned with laminated cones, kapton formers and aluminium voice coils. Dedicated to the Model 1, to which it crosses over at 220Hz, the sub extends the frequency downward to 36Hz and increase the power handling from 100W to 200W.

Connection of satellite-to-sub is as per LS3/5A-plus-AB1 and WATT-to-Puppy: the amplifier is connected to the sub, and the sub is connected to the satellites. You can also bi-wire the upper section, but I preferred this in single-wire mode, which appeared to offer smoother frequency transitions. For identifying both the gains in bass extension and the effects of the various connecting options, I turned to last year's Kodo drummer releases and the new George Clinton hits compilation on Capitol. Believe me: you acquire more than mere weight by adding the woofer sections.

Dynamic contrasts widened, and for whatever reason, the upper registers seemed faster and more precise. Another contender in an already crowded arena, the Indigo's competitive worth consists of more than coloured grilles: this is a refined performer which marries BBC-like composure with an ability to provide the bass and levels required of listeners who, er, rock. And while Indigo does make a one-piece floorstander, the Model Four at £750, it enjoys one less bass unit, and requires an initial outlay larger than that of the small Indigos. You can always aspire to the Stage One in two installments.