It was only a matter of time before Ruark added an entry-level model to its flagship series. I'm completely puzzled as to why this brand needs as many ranges as it has, but, hey, I'm just a reviewer. What the Sterling Reference line has succeeded in doing - for me at least - is become the range and the look that I first think of when someone says 'Ruark'. Which is as it should be: this is the most distinctive sub-sector in the company's catalogue, and it's only fitting that one pictures the best on offer before recalling the entry-level.

Additional Resources
• Read more floorstanding speaker reviews from HomeTheaterReview.com.
• Find a subwoofer to integrate with the Solus.

In the six years since the stand-mounted two-way Equinox launched the line-up, it has been joined by the Solstice and Excalibur floor-standing behemoths. Solus is the newbie which completes the series, though Sterling Reference will eventually include a centre channel speaker and a subwoofer for obvious home theatre applications. This is of paramount importance in understanding the full potential of Solus, because - while it's good enough by any standard to serve as a main speaker - it's also small enough to act as rear or side speakers in systems where Equinox or Solstice (if not necessarily Excalibur) act as the primaries.

And it small; it seems like a mini version of the Equinox, measuring a concise 330x206x330mm (HWD). Compact it may be, but the Solus weighs 10kg, hinting at chunky components and solid construction. Ruark has trademarked its cabinet technology, which goes by the name of ACD (Advanced Cabinet Design), a method of assembly indicating varying panel thickness and strategically-positioned bracing to minimise resonance. Resonances which the ACD construction cannot inhibit are said to be 'low in amplitude but broad in spectrum and add to the tonal rightness of the design giving the speaker its own unique character'. Somebody must have hired Mandelson to dish out spin...

By now, you know the look: sculpted side panels, a black 30mm thick Boothroydian grooved, black slate-textured top, baffle and rear panel - very sandwich, very Italian. And very inert. The combination of intricate internal bracing and acoustic deadening material, do achieve what Ruark wanted it to accomplish, resulting in a box which passes the thump test; it's almost completely inert and, as the sound attests, free from the effects of coloration. Its slightly inclined front baffle provides time delay, protected by a removable grille, but I didn't find it intrusive enough to feel compelled to remove it. Taking no chances, the Solus is available with its side panels in natural oak, black oak and natural cherry, with yew, natural beech, rosewood or black piano lacquer as options.

Solus also revives a practice almost entirely abandoned by manufacturers who reject it because it adds a step or two to the manufacturing process: offset drivers. It adds to the cost because it requires the manufacture of mirror-imaged pairs, unless the baffle is the same on both surfaces and can simply be flip-flopped to create the left and right versions. What it allegedly offers are better integration, dispersion and room flexibility.

A gas-flowed rear port is situated at the top of the rear baffle to allow this small box to deliver 'excellent subjective bass extension'. According to Ruark, reflex loading was required to maximise the performance of Solus' low Q bass driver, relative to the volume of the enclosure. The latter was determined by 'pseudo anechoic measurements', along with auditioning in several different rooms, with fine-tuning to extract the maximum bass extension. Solus' largish port also maintains the performance at high volumes because small ports cannot move enough air at high SPLs. As a result, the Solus avoids compression and is nearly as capable as a small ATC in achieving rock-lover volume without sounding like it's about to explode.

Solus sports a Scanspeak-made, 28mm silk dome tweeter using a doped open weave fabric. The dome is fitted to an aluminium former and voice-coil, immersed into a low viscosity ferro-fluid. The latter contributes in no small part to the high power handling, its low viscosity having 'minimal drag' to endow the tweeter with speed - evident in listening sessions via some of the fastest transients I've heard; cynics will notes that speed of this high a calibre is normally the virtue of metal drivers...probably the virtue of metal drivers. The tweeter assembly also includes a machined air-flowed pole-piece leads to a rear chamber which serves 'to equalise pressure on the rear of the dome and suspension'.

But the star of the Solus is a newly-designed 150mm woofer, heard here in its first real-world application. The company devised a unique damping method applied to the long fibre, profiled paper cone, which was selected initially for its intrinsic internal damping. Slits were cut into the cone in an outward spiral at different angles from the dust cap to the pure rubber surround, the latter a material with minimal hysteresis and energy storage; the pattern reminded me of the lozenge-shaped pits on some Linn speaker baffles. The slits are filled with a 'secret' damping compound, then treated to a final coating of dope on the cone surface.

Ruark believes that this process 'effectively dissipates and controls vibrations around the cone instead of reflecting them straight back to the centre'. Their chosen illustration of this phenomenon is the path of ripples when you throw a stone into a small pool. The absence of any damping of the waves created by the stone means that the ripples will reach the bank and then be reflected back into the pool. Apply this to sound and it means coloration. Better control of cone behaviour should result in smoother response and lowers colouration up through the midband.

Another detail of the new woofer assembly is its precision die-cast chassis, conceived to deal with how sound waves were dispersed at the rear of the chassis, along with the loading effect of air on the unit's long throw coil and suspension. Its struts, which hold the driver's magnet are - I kid you not - 'aerodynamically shaped to present minimal resistance to internal sound waves'. The design approximates the suspension working in free space, rather than in a chamber. Another aspect of the suspension is its ability to provide linear movement under 'normal working conditions', turning 'progressive' at the extreme. This also adds to the Solus' ability to be hammered by headbanging morons before the arrival of compression at obscenely high volume levels.