Quadral's German engineers know how to have fun with extruded aluminium shapes and flattened drive units.

But at least their strange predilections mean that we're getting to see some extraordinary all-metal home cinema speakers. The latest is the Signo series, which boasts some of the slimmest and most rigid cabinets on the market.

And, with all the brushed aluminium, wooden panels and glass pedestals, they're some of the funkiest-looking speakers on the scene too.

Small footprint

The Signo lineup includes nine different speaker models to mix and match from. The configuration tested here, consists of floorstanding fronts, small surrounds, and 10in subwoofer, adds up to £1,500.

The grills don't come off, but inside the cabinets you'll find Quadral's own proprietary drivers, which, in the case of the bass units, use small neodymium magnets positioned in front of the diaphragm, rather than behind it, to make them flatter. This is one reason why all five of the speakers are just 6.5cm deep.

When in situ, they take up a very small amount of living room but still present an impressive full-range capability. Perfect partners then for a flatscreen TV?

Rigid speaker design

Build quality is impressive, with metal panels screwed tightly together to create a sturdy construction. Audio-wise, the very rigid structure helps to keep the delivery tight, and the curved shape eliminates standing waves inside the cabinet.

At the base is where you'll find the speaker binding posts. There are just two of these, even on the floorstanders, so you can forget about bi-wiring.

Even more frustratingly, they are deliberately too shallow to take a 4mm banana plug, which are (infuriatingly) outlawed in the EU, leaving you with the option of spade or bare wire connections only.

And to make sure the Signos don't clash with your décor, each speaker has interchangeable side cheeks. You can buy these wooden columns separately, choosing from beach, cherry, silver or black finishes. The base plates come in metal and glass options, too.

Pump up the bass

Anyone eager to assemble a Signo system would be wise not to be seduced by the cheaper 5.0 option and skip on the subwoofer. The Sub 250 DV is essential in this setup as the other five speakers are a little bass-shy.

Beginning my audition in stereo mode doesn't bode especially well for the skinny Signos. I quickly noted that the balance here leans very much toward the top-end, with sharp, almost shrill treble, crisp mid-band and very little bass extension.

A long running-in period took the edge off the treble, however, and brought out a little more expression in the vocals, but really they need a good bass sidekick to handle the low frequencies.

Lucky this system came with a decent subwoofer then. The Sub 250 is pretty hefty, as, like the rest of the speakers, it's largely made of metal plates screwed together with heavy wooden trim.

The bass reflex cabinet is ported at the bottom with a front-firing woofer. Its nominal power of 150W is quite modest, but it's enough to transform this system into an expressive and cohesive unit.

Accurate detail

In 2.1 mode, the subwoofer takes care of the lower-midrange, to let the twin towers field the tricky delicate stuff. Their 25mm fabric dome tweeters are also Quadral's own design and seem capable of precision timing.

If you set the frequency and volume of the sub just right, with some extensive listening you'll be rewarded with fast, agile basslines and crunchingly accurate detail.

The only downside is that in jumping from stereo speakers to a sub/sat system you loose some imaging and realism, with the bass frequencies sounding a little disjointed.