To shun subwoofers because of some imagined association with the Dark Side is to ignore a noble history, and with British and Continental rather than just American precedents. Indeed, while M&K and other pioneers in the States were developing bass augmentation systems for domestic and pro use, UK legend Jim Rogers offered an active sub for his delicious JR149s. So, to set the tone, guys, subwoofers are politically correct in two-channel terms. The audiophile problem has always been one of integration.

Read more high end audiophile subwoofers from Sunfire, Paradigm, B&W, PSB, SVS and many more.

This is why REL carved a niche as a subwoofer-only specialist, before the calling came to exploit multi-channel. REL's designs are the rare exception, universal subwoofers in the truest sense. From the outset, REL's subs have offered the most thorough arsenal of settings for integrating their products with the widest range of main speakers, including dipoles, electrostatics and others that exhibit an almost wilful refusal to accept external bass support. Without apology, they are complicated enough to warrant a 32-page instruction manual, the net result being that your labors will produce a sub/main speaker blend with a seam that's impossible to detect.

Although the range is mature and virtually above reproach, the brand's biggest market - the USA - demanded something more. And before you start accusing Yanks of an unnatural love for deep bass, assuming that they only listen to Snoop Dogg at 140dB, chew on this for a while: Americans are blessed with larger rooms.

REL certainly doesn't dress up its subs, so I'll let the pictures tell the story rather than kvetch about something most people will hide anyway. Build quality is rock solid, and - despite dimensions of 343 x 610 x 410mm (WHD) - the B2 is a sod to move around: the massive 10-inch woofer, audiophile-grade electronics and solid construction contribute to a 38kg total.

REL isn't prissy about positioning: the manual offers a number of degrees of anal-retentiveness, with chapters entitled "REL Set-Up Made Simple" and "REL Set-Up Made Simple." Because you'll be eager to have it up and running, these are the instructions you'll use at first. You can dig into the meatier parts after the unit is run in, and you feel comfortable with the changes it makes to your system. It's like beginning with the "quick start guide" with a new mobile phone or computer before deciphering the bits about setting up LANs.

Upon braving the set-up possibilities, you'll find more tweaking fun than anything this side of a linear-tracking tonearm. REL's B-Series subs provide 24 crossover frequencies from 22-96Hz, using precision-trimmed circuits, high level and low level inputs through a variety of connectors, fine and coarse roll-off - they left no variable untouched. And this subwoofer can be optimized for either two-channel or '.1' roles.

Where the REL really shows its stuff is in the way it handles what can only be described as "sub bass." However deep you think your system goes, this extracts that little bit more. As REL's John Hunter put it, the topology "approximates a transmission line. The merits of REL's approach to true sub bass has been catalogued by many, so I'll simplify it down to a profound ability to accurately, tunefully play the very lowest registers - the sort of thing where the walls begin to distort and the floor ripples with true infra bass - the area in which this occurs is the sub-35hz range."

Hunter continues, "In the B-Series, a forward-firing driver affects the improved slam and attack, as well as carriage, we were looking for but features a complex rectangular-to-round inner chambering [like a poor man's ARM loading] that ultimately vents to a down-firing port. The result is the synthesis of many previous REL ideas into, we believe, a better whole. We have delivered about 96 percent of Stentor-like low bass with better upper and middle bass registers, at about 30 percent less money."

To ensure that I was hearing what the B2 could do, REL set up the sub to augment my Sonus faber Guarneris, which was logical, as the US distributor for REL also handles Sonus faber. In under an hour, the B2 was matched to the Guarneri, crossing over at a low 22Hz - a benefit of having a rock-solid listening room which obviated the need to cross over any higher. With McIntosh valve electronics, Marantz CD12 and an SME analogue front-end, I sat back, eager to learn about the area of sound that matters least to me: deep, deep bass.

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