Q Acoustics Q Active 400 Floorstanding Speakers White (Pair)

The Q Active 400 is Q Acoustics' flagship active floorstanding speaker, sitting above the standmount Q Active 200 in the Q Active range. Where the Q Active 200 introduced Q Acoustics' first true active speaker system, the Q Active 400 extends the concept into a floorstanding enclosure with dedicated bass drivers and substantially more amplifier power.

BMR Driver Technology

Each Q Active 400 speaker carries a pair of 58mm (2.25") Balanced Mode Radiator (BMR) full-range drivers, mounted in an offset configuration. BMR drivers operate in both pistonic and modal modes across their frequency range, producing a far wider dispersion pattern than conventional dome or cone tweeters. The offset mounting of the two BMR units creates what Q Acoustics describes as a widescreen sound dispersal with a large sweet spot, reducing the need for precise listener positioning.

Dual-Opposing Subwoofer Design

Below the 150Hz crossover point, bass duties are handled by two rear-firing 114mm (4.5") high-excursion subwoofers per speaker. Rather than placing both drivers together, Q Acoustics positions one subwoofer at the top of the cabinet and one at the bottom. This dual-opposing arrangement neutralises the cabinet's internal standing waves, reducing unwanted resonance and delivering a cleaner, tighter bass response. The reflex (ported) enclosure extends the system frequency response down to 35Hz at the −6dB point.

Amplification & DSP

The Q Active 400 is a fully active design with eight discrete Class D amplifiers — four per speaker — delivering 140W continuous and 440W peak power per speaker. Each driver receives its own dedicated amplifier channel, allowing the crossover and equalisation to be handled entirely in the digital domain before amplification. This eliminates the losses and phase shifts inherent in passive crossover networks.

Q Active Control Hub

The system is centred on the included Q Active Control Hub, a compact unit measuring just 40 × 180 × 112mm. The Hub acts as the system's input stage and wireless transmitter, connecting to both speakers via a dedicated 5.8GHz hi-res wireless link. It accepts a maximum source resolution of 32-bit/192kHz, which is converted to 24-bit/96kHz for wireless transmission.

Wired inputs on the Hub include HDMI ARC (96kHz/16-bit, 2-channel), digital optical Toslink (96kHz/24-bit), analogue line-level (300mV/18kΩ), and a built-in MM phono stage (2.6mV/47kΩ, RIAA equalised) for connecting a turntable directly. A subwoofer output is also provided. Network connectivity covers Wi-Fi (IEEE 802.11 a/b/g/n/ac), Bluetooth 4.2 LE, and Ethernet.

Streaming & Voice Control

The Q Active 400 supports Apple AirPlay 2, Google Chromecast built-in, Spotify Connect, and Roon. Supported audio codecs include AAC, WAV, FLAC, MP3, Vorbis, WMA, and ALAC. Voice control is available via Google Assistant and Apple Siri.

Room Adaptation

Rear-mounted switches on each speaker allow the user to designate left and right channels and specify the speaker's placement — near wall, corner, or free space. The system uses this information to fine-tune its low-frequency response for the listening environment.

Also Available As

The Q Active 400 is also available in Black.