Q Acoustics Q SUB120 Active Subwoofer at Vinyl Sound Buffalo NY USA

The Q Acoustics Q SUB120 is a 12-inch active sealed subwoofer from Q Acoustics (United Kingdom), available at Vinyl Sound USA Inc. in Buffalo, NY. The flagship model of the Q SUB series, the Q SUB120 houses a 305 mm paper-cone driver with a 50 mm aluminium voice coil and demodulation ring in an 18 mm high-density MDF infinite baffle enclosure with a 36 mm double-thickness baffle and internal dart bracing. A custom-designed amplifier module with four digital power amplifier stages in a parallel bridge-tied load PBTL configuration delivers 600 watts peak and 300 watts continuous power with THD below 0.1% at rated output. On-board DSP provides a low-pass crossover adjustable from 40 Hz to 250 Hz, dual phase and delay controls, automatic input signal detection, and a phase inversion switch, extending frequency response down to 28 Hz with a maximum SPL of 114 dB at 1 metre. The Q SUB120 is designed for seamless integration with any Q Acoustics loudspeaker system, any existing stereo or multichannel setup, or powered speaker systems requiring low-frequency extension.

305 mm Driver, 50 mm Voice Coil, and PBTL Amplifier Architecture

The Q SUB120's 305 mm paper-cone driver uses a heavy-duty steel chassis, a rubber surround, and a 50 mm voice coil — a larger coil diameter than the 38 mm units in the smaller Q SUB80 and Q SUB100, providing greater motor area for the higher excursion demands of a 12-inch driver at high output levels. An aluminium demodulation ring on the pole piece reduces inductance-induced modulation distortion, the nonlinear distortion mechanism that causes voice coil inductance to vary with excursion and produces harmonic and intermodulation artifacts at high drive levels. The custom-designed amplifier module uses four Class D digital power amplifier stages in a PBTL configuration, a topology that connects two amplifier stages in bridge mode per channel and then parallels the two bridge pairs. PBTL reduces output impedance, increases the amplifier's current delivery capability, improves efficiency, and decreases heat dissipation relative to a conventional bridge design, enabling the 300-watt continuous and 600-watt peak rating with THD below 0.1% across the full rated output range.

Sealed Infinite Baffle Cabinet, DSP Room Integration, and Automatic Source Detection

The Q SUB120 uses a sealed infinite baffle enclosure rather than a ported design, a choice that delivers a tighter, more focused bass response with a more gradual and controllable roll-off characteristic below the tuning frequency. Without a port to introduce port noise, port resonance, and driver unloading at very low frequencies, the sealed enclosure allows the DSP to tune the system's acoustic response more precisely, and the absence of a rear-firing port makes near-wall and corner placement significantly more practical than ported designs of equivalent driver size. The DSP system provides automatic source detection that identifies incoming signals as stereo or mono and adjusts system gain accordingly, ensuring optimal signal-to-noise ratio and dynamic range regardless of the connected source type. Dual delay and phase controls allow fine-tuning of the subwoofer's time alignment relative to the main speakers, addressing the arrival-time offsets that commonly arise from subwoofer placement at a different distance from the listening position than the main loudspeakers. A phase inversion switch handles the 0 to 180-degree phase relationship between the subwoofer and main system, and the continuously variable low-pass crossover from 40 to 250 Hz accommodates everything from full-range main speakers requiring only deep bass augmentation to compact bookshelf speakers whose bass roll-off begins above 100 Hz.

Key Features

• 305 mm Paper-Cone Driver: A 12-inch heavy-duty driver with steel chassis, rubber surround, and 50 mm voice coil delivers bass extension to 28 Hz at 114 dB maximum SPL, suitable for large rooms and high-output home cinema systems.
• Aluminium Demodulation Ring: A demodulation ring on the pole piece reduces inductance-induced modulation distortion at high excursion levels, maintaining clarity and low distortion under demanding dynamic conditions.
• PBTL Class D Amplifier: Four digital amplifier stages in a parallel bridge-tied load configuration deliver 300 watts continuous and 600 watts peak with THD below 0.1%, combining high efficiency with exceptional output current capability.
• DSP Room Integration: On-board Digital Signal Processing provides dual delay and phase controls, phase inversion switch, and automatic input signal detection for owner-adjustable subwoofer-to-main system integration without professional installation.
• Variable Low-Pass Crossover: A continuously adjustable low-pass filter from 40 to 250 Hz accommodates integration with any partnering loudspeaker system from full-range towers to compact bookshelf speakers.
• Automatic Source Detection: DSP identifies incoming signals as stereo or mono and adjusts system gain automatically for optimal signal-to-noise ratio from any source type including stereo preamp outputs, mono AV receiver feeds, and active speaker line outputs.
• Sealed Infinite Baffle Design: A portless sealed enclosure delivers tight, focused bass with a controlled roll-off, easier near-wall placement than ported designs, and a lower noise floor free from port turbulence artifacts.
• 18 mm MDF Cabinet with 36 mm Double-Thickness Baffle: High-density MDF cabinet construction with a doubled front baffle and internal dart bracing suppresses cabinet resonance and prevents ballooning under the high internal pressure generated by 600-watt peak amplification.
• Two Classic Finishes: Available in Satin Black with a black grille or Satin White with a grey grille for discreet placement in any interior environment.

Technical Specifications

Frequently Asked Questions

What is the Q Acoustics Q SUB120?

The Q Acoustics Q SUB120 is a 12-inch active sealed subwoofer from Q Acoustics, UK. It houses a 305 mm paper-cone driver with a 50 mm aluminium demodulation ring voice coil in an 18 mm high-density MDF infinite baffle cabinet with a 36 mm double-thickness baffle and dart internal bracing. The PBTL Class D amplifier delivers 600 watts peak and 300 watts continuous with THD below 0.1%, and DSP provides a variable 40 to 250 Hz low-pass crossover, dual delay and phase controls, automatic source detection, and a phase inversion switch. Frequency response extends to 28 Hz at a maximum SPL of 114 dB at 1 metre.

How does the Q SUB120 compare to the Q SUB80 and Q SUB100?

All three Q SUB models share the same sealed infinite baffle cabinet design, PBTL Class D amplifier architecture, DSP integration system, and 300-watt continuous amplifier rating. The Q SUB80 uses a 203 mm eight-inch driver with a 38 mm voice coil and extends bass to 36 Hz. The Q SUB100 uses a 254 mm ten-inch driver with a 38 mm voice coil and extends to 32 Hz. The Q SUB120 uses the largest 305 mm twelve-inch driver with a larger 50 mm voice coil and extends deepest to 28 Hz, with the highest maximum SPL of 114 dB. The Q SUB120 is the correct choice for large listening rooms, high-output home cinema systems, or integration with full-range floorstanding speakers where bass extension below 30 Hz is required.

How does the Q SUB120 compare to the SVS SB-2000 Pro and the REL T/9x?

The Q Acoustics Q SUB120 competes directly with the SVS SB-2000 Pro and the REL T/9x in the premium sealed 12-inch subwoofer category. The SVS SB-2000 Pro uses a 12-inch driver with 550 watts RMS Sledge amplification and app-based DSP control via Bluetooth, extending to 18 Hz at the -6 dB point. The REL T/9x uses a 10-inch driver with 300 watts amplification in a sealed enclosure with REL's high-level speaker cable input as its primary connection. The Q SUB120 matches the REL T/9x's continuous power rating, extends deeper than the T/9x's 10-inch driver, and adds the DSP delay and phase controls that REL does not provide, making it more flexible for non-ideal room placement scenarios. Against the SVS SB-2000 Pro, the Q SUB120 offers comparable output at a similar price with Q Acoustics-specific voicing suited to integration with the 5000 and Concept series speaker families.

What is the advantage of a sealed over a ported subwoofer design?

A sealed infinite baffle subwoofer rolls off more gradually below its tuning frequency than a ported design, which rolls off more steeply below its port tuning but can produce higher output at the port frequency. Sealed subwoofers are generally preferred for music listening where bass accuracy and pitch definition are priorities, and for rooms where corner and near-wall placement is necessary, as the absence of a rear-firing port eliminates the port noise and boundary interactions that ported designs exhibit in those positions. The Q SUB120's sealed design also allows the DSP to apply precisely controlled bass boost and group delay correction below the natural roll-off point, effectively extending useful output below what the passive enclosure alone would deliver.

How is the Q SUB120 integrated with a stereo or home theater system?

The Q SUB120 connects via its line-level RCA inputs from an AV receiver's subwoofer pre-out, a stereo preamplifier's line output, or the line output of an active or powered speaker. The variable low-pass crossover from 40 to 250 Hz is set to match the bass roll-off point of the main speakers. The delay control adjusts timing to compensate for the subwoofer being placed at a different distance from the listening position than the main speakers, and the phase control optimizes the phase relationship between the subwoofer and main system at the crossover frequency. The automatic source detection adjusts gain for stereo versus mono input sources without manual intervention. Vinyl Sound Buffalo can assist with integration setup and crossover matching for your specific speaker system.

Where can I buy the Q Acoustics Q SUB120 in Buffalo or Western New York?

The Q Acoustics Q SUB120 Active Subwoofer is available at Vinyl Sound USA Inc., an authorized Q Acoustics dealer in Buffalo, NY, serving audiophiles across Western New York and the greater Buffalo region. Vinyl Sound can assist with subwoofer integration, crossover setup, and complete system consultation in-store or by appointment.