Q Acoustics Q SUB 120 Subwoofer White

The Q SUB 120 is the flagship of Q Acoustics’ Q SUB active subwoofer series, sitting above the 8-inch Q SUB80 and 10-inch Q SUB100. Built around a 305mm (12”) bass driver with a 50mm voice coil, it delivers 300W continuous and 600W peak power through a custom-designed Class D amplifier module, reaching down to 28Hz and producing a maximum SPL of 114dB at 1 metre.

Driver & Amplifier Design

The 305mm bass unit uses a heavy-duty steel chassis, paper cone, and rubber surround. The voice coil incorporates an aluminium demodulation ring to reduce inductance-induced modulation distortion. Four digital power amplifier stages operate in a parallel bridge-tied load (PBTL) configuration, reducing output impedance and heat dissipation while delivering total harmonic distortion of just 0.09% at the full 300W rated power.

DSP & Room Integration

Digital Signal Processing is central to the Q SUB 120’s design. The DSP automatically detects whether the input signal is stereo or mono and adjusts system gain accordingly, optimising signal-to-noise ratio and dynamic range regardless of the connected source. Fine delay adjustment and a phase inversion switch allow precise time-alignment with partnering speakers, addressing room placement challenges without the need for professional calibration. The adjustable low pass filter covers 40Hz to 250Hz, setting the −6dB point to match the roll-off of virtually any speaker system.

Cabinet Construction

The Q SUB 120 uses an infinite baffle (sealed box) enclosure with an effective internal volume of 44.1 litres. The cabinet is constructed from 18mm high-density MDF with a 36mm double-thickness front baffle for rigidity. Internal dart bracing enhances mechanical stability under high internal pressure, reducing cabinet ballooning and colouration. The sealed design delivers tight, focused bass and simplifies placement near walls and furniture compared with ported alternatives.

Finish & Placement

Available in Satin Black with a black grille or Satin White with a grey grille, the Q SUB 120 is designed to blend discreetly into any listening environment. It partners naturally with Q Acoustics’ own speaker systems — including the 3000i, 5000 series, and Concept ranges — but its comprehensive DSP and wide crossover range make it equally suited to integration with third-party speakers.