The new QR subwoofer is actually the second of two models in the Audiovector line-up, although in the spirit of other Audiovector SR models, the SR Sub is available in Super, Signature, Avantgarde, and Avantgarde Arretè variants. The QR Sub is a more down-to-earth design, with few options as befits products in the company’s entry level QR range: just the choice of black, white, or wood finish in fact. But ‘down-to-earth’ does not mean ‘rudimentary’. This is a very sophisticated subwoofer in and of itself.
The QR Sub uses the trusted combination of forward-firing active and down-firing passive drivers, fed by a powerful amplifier, and includes both high- and low-level inputs for use in audio and audio-video systems. It’s a natural partner for the QR range.
To recap, that QR range is Audiovector’s entry-level range, which features an AMT tweeter and what it refers to as a ‘Pure Piston’ driver for midbass. In a subwoofer, you can forget about the tweeter, but the Pure Piston driver design is used here, in a larger 250mm form. Pure Piston is essentially a sandwich, with aluminium acting as bread, either side of a fibre-filled foamy glue replacing the cheese. So far, there have been discussions about the use of pickle. Lunchtime hunger aside, the point of the Pure Piston driver technology is to use the filling to mitigate the break-up properties of aluminium cones, and the aluminium cones to act as constrained layers for the filling itself. This combines to make a driver that has a ‘best of both’ set of properties, retaining the light and reactive performance of an aluminium cone, without the potential for cone break-up in the audible frequency range. In a subwoofer, especially when faced with a long-throw auxiliary bass radiator firing downwards, cone break-up could significantly interfere with the Presence region, and instead of underpinning a good loudspeaker, the QR Sub would ruin it at a stroke. Fortunately, the Pure Piston drivers seem pathologically incapable of making a poor sounding subwoofer. And, fed by that 350W amplifier, they are well controlled and capable of both surprising depth, and surprising subtlety. The amp can be used auto-sensing, and includes two volume settings, a frequency adjustment, and phase.
The frequency and volume adjustments for stereo loudspeakers only kick in when you use a high-level cable, unfortunately provided as an optional extra. This includes a Neutrik Speakon connector and three wires, designed to be connected to the speaker terminals of your amplifier (the surround sound option takes a phono input feed (the cables for which is also not supplied, and you should use left and right inputs even if you only have a single subwoofer output. Audiovector recommends a Y-splitter). If you are using this in a stereo context, I would recommend using the high-level connections even if there is a subwoofer output on your amplifier, primarily because it sounds better. It can also be made to sound better still with REL’s Bass Line Blue cable.