Q Acoustics Q SUB 100 Subwoofer Black

The Q SUB100 is the mid-range model in Q Acoustics' Q SUB series of active subwoofers, sitting between the compact Q SUB80 and the larger Q SUB120. Designed for medium-sized rooms, the Q SUB100 pairs a 254mm bass driver with a custom-designed 250W amplifier module to deliver controlled, low-frequency extension down to 32 Hz.

Amplifier Module

The amplifier module is custom-designed by Q Acoustics and integrates a DSP engine, power amplifier, and power supply into a single unit. Four digital power amplifier stages operate in a parallel bridge-tied load (PBTL) configuration, which reduces output impedance and heat dissipation while improving speaker control. The result is 250W of continuous power and 500W peak, with total harmonic distortion measured at 0.09% at rated power. Maximum SPL reaches 111 dB at 1 metre.

Digital Signal Processing

On-board DSP handles several integration tasks that would otherwise require external processing. The system automatically detects whether the input signal is stereo or mono and adjusts gain accordingly, ensuring optimal signal-to-noise ratio and dynamic range regardless of the connected source. Phase inversion and fine delay adjustments are provided for room integration, allowing users to compensate for placement-related timing differences without professional calibration.

Low-Pass Crossover

The adjustable low-pass filter covers a wide range from 40 Hz to 250 Hz, setting the -6 dB point where the subwoofer's output rolls off to meet the bass response of partnering speakers. This unusually broad adjustment range ensures the Q SUB100 can integrate with anything from small bookshelf speakers to large floorstanding models.

Driver Construction

The 254mm bass driver uses a heavy-duty steel chassis with a paper cone and rubber surround. A 38mm voice coil is fitted with an aluminium demodulation ring, which reduces inductance-induced modulation distortion for cleaner output at higher drive levels.

Cabinet Design

The Q SUB100 uses an infinite baffle (sealed box) design, which delivers tighter, more controlled bass than a ported enclosure and simplifies room placement — with no port to manage, the subwoofer can be positioned close to walls and furniture without adverse effects. The cabinet is constructed from 18mm high-density MDF with a 36mm double-thickness front baffle for rigidity. Internal dart bracing further reduces cabinet resonance and ballooning under high internal pressure. The effective internal volume is 23.5 litres.

Connectivity

Inputs include stereo RCA analogue connections (which also accept a mono LFE feed from an AV receiver), a 12V trigger input for automatic power-on from a compatible amplifier or processor, and a USB-C port. An auto on/off function is also provided.