Its name may suggest roomshaking power, but Tony Williams finds there's more to Ras smallest bass unit than that.

Originally printed in the February 2003 issue of Gramophone.

From its beginnings just over 10 years ago, Welsh company REL Acoustics has developed a range of speakers with one aim: the underpinning of systems with bass of exceptional quality. The original Stadium subwoofer was hardly compact, and the current Studio III is enormous, at around 60cm on each side and weighing a massive 93kg. Yes, it can deliver prodigious bass, thanks to twin 25cm drivers and a 500W amplifier, but it's overkill for most rooms and systems, even should you have space to accommodate it.

REL's real strength, however, has been its ability to deliver bass systems for all needs, right down to the relatively compact Q range: the Q150E is established as a classic choice, whether the requirement is for a more extended low-end with music or the low frequency effects from Dolby Digital or DTS soundtracks. Now there's an even smaller REL subwoofer — the Quake — designed to extend the range's appeal to those with very small rooms (or maybe just very little space).

It's tempting to see the Quake as a response to the publicity gained by MJ Acoustics' Pro 50, a similarly compact British design launched a little over a year ago. The Pro 50 has been a favourite of these pages since it was first tested, and it's easy to imagine that its arrival rather caught REL on the back foot, and prompted the Quake's introduction. Whatever the reason, the new model is the smallest ever sold by Richard Lord's company, and very affordable at £50 in Brittex black paint, or more in a cherry wood balanced veneer. The benefits of the latter finish are greater than just looks — the veneer technique, in which wood is applied both inside and out, also stiffens and deadens the cabinet.

The woodwork itself is to the usual high REL standards, and just the fact that this is an entry level model shouldn't be taken to suggest that corners have been cut. Far from it: the compact unit — it's less than 30cm on each side — is still hand-built, and uses a high quality 20cm driver in a steel chassis, driven by a 100W direct coupled MOSFET amplifier fed from a toroidal transformer. The drive unit has 150W power handling, so is pretty much under stressed even when running at full power; but as usual, REL has built in its Set Safe protection circuit to avoid potential damage.

Controlling the Quake is easy once you understand the way the company thinks. There's a version of the REL ABC filtering circuit to allow integration with existing stereo speakers, while switching is also available for filtered or full range operation (for example when the subwoofer is used with the LFE output of an AV processor or amplifier).

Phase can be switched between normal and inverted — setting this one is a bit of a trial and error operation — and you can choose between 'slam' and 'depth' settings. The former gives tighter bass with a little less extension, the latter lower bass but at the expense of some speed. Other controls extend to separate level settings for the line input and speaker level connections, and both high and low-level connections could be used together, for example, so that one setting could used for music, the other for film soundtracks.

Performance

With its downward-firing drive unit and sealed-box enclosure, the REL is less fussy about positioning than some models using forward-firing drivers and ported bass loading, which can be prone to bass boom when used close to walls or in corners. Wherever I tried the unit in my listening room it was possible to 'dial it in' to give a smooth integration with the main speakers, and optimise bass extension.

It would be perfectly possible to run a pair of them should you feel the need for more bass or just stereo bass, even though most of the content handled by this speaker is of so low a frequency as to be non-directional. I tried the Quake connected to an AV receiver in a multichannel home cinema system, but most of my listening was carried out with the REL connected to Rotel's RCD-02/RA-01 system driving PMC's DB1 speakers. The PMCs were chosen deliberately for their already well extended bass (down to 50Hz) as I wasn't interested in exploring the REL's role in a satellite and woofer system, but rather seeing what it could do with speakers already competent in the low frequency spectrum.

To that end the Quake was connected up to the Rotel amplifier at speaker level, and its ABC selector used at position 1 (filter engaged, phase normal), while the upper frequency roll-off was set to just overlap the PMC's 50Hz lower limit. Some slight adjustment of the high-level gain to reach the point where the subwoofer 'disappeared' — aurally, at least — and I was ready to listen.

It was immediately clear that the Quake was making a useful contribution to proceedings, and one a long way from the common misconception of boom and thump. Yes, the bass was more extended, particularly noticeable in the weight and power of orchestral basses and percussion, organ music and the resonance of the lower registers of solo piano, but more to the point there was a greater sense of freedom in the sound. And given how good the PMCs are unaided, as AE noted in his review two months ago, the gains available from adding this little cube to the system are all the more impressive.

The Quake can make even accomplished speakers sound so much bigger and more powerful, but it also seems to bring to the presentation a greater impression of openness and air, whether it's the ambience of a concert hall or the feeling of closeness in a studio recording of chamber or solo performances. That's not a trait unique to this unit — indeed it's been noted with many a good subwoofer, in these pages and elsewhere — but the REL manages to pull it off with no sense of artificiality being introduced into the sound. For that reason this is likely to be as much a factor in its appeal as all-out bass extension.

When you consider how little space this subwoofer occupies — it really could be hidden away under a coffee-table or beside a sofa — and its very reasonable price, the attraction of the REL Quake is fairly apparent. Like the slightly less expensive, but less powerful, MJ Acoustics Pro 50, this is certainly a system upgrade well worth considering. REL's smallest and most affordable subwoofer is still able to underpin serious loudspeakers.