As the name suggests, Sub Zero II is the successor to the Roth Sub Zero, a soundbar designed to boost audio quality from terrible-sounding TVs without the need for a separate subwoofer (see what they did there?). It does this by squeezing a bunch of active and passive bass drivers into the soundbar’s slender frame, making it perfect for rooms where space is tight. Roth reckons this new incarnation builds on the performance of its predecessor and throws in a few extra features, including Bluetooth and DSP sound modes – all of which sounds pretty tasty for just £150.
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Sub Zero II is a solidly built and tastefully designed soundbar. Its robust reinforced polymer cabinet is covered in a classy black cloth that keeps everything clean and minimal. At just 850mm wide it’s ideally suited to TVs between 32 and 47-inches, and it can be mounted on the wall using the supplied brackets or on a tabletop.
It’s worth noting that Sub Zero II is a different animal to its predecessor. Gone are the slanted Vector Firing side drivers and Fractal Expansion technology – this version takes a simpler forward-firing approach.
The front-mounted control panel is now smaller and more discreet, but its rudimentary feel betrays its budget price tag, opting for lights and hard, clicky buttons where others might use LED readouts and touch-sensitive controls. Still, that’s perfectly acceptable at this price.
The panel features a large power button and four other keys to control inputs, sound modes and volume. The volume level is indicated by a row of five purple lights, which are quite hard to see from the sofa. These LEDs disappear when idle.
Rear connections are strictly old-school, with no HDMI inputs to be seen, but an optical digital input allows you to pipe audio from your TV (and any sources connected to it).
It’s joined by stereo RCA input and a 3.5mm minijack. You should connect your TV’s headphone output to the latter if you want to control volume with your TV’s remote, but connect via optical or RCA to use Sub Zero II’s remote.
There’s no USB port for playback of audio files but again we refer you to that £150 price tag. This line-up is more than adequate for what is essentially an extension of your TV’s speakers.
Sub Zero II’s standout feature is built-in Bluetooth with apt-X, which offers a step-up in performance over regular A2DP technology. Streaming music from phones, laptops or tablets couldn’t be simpler.
Sub Zero II’s driver array includes four 2.5in ferrite drivers – two bass, two full range – plus a pair of ‘Ultra-Bass’ passive radiators. The Class D amplifiers kick out 60W of power, while Roth’s MA DSP (digital signal processor) offers three sound presets – Movie, Music and Voice.