Allen & Heath Qu-SB Compact 18-In/14-Out Surface-Less Digital Mixer

Allen & Heath Qu-SB: The Full Qu Mixer Without a Fader in Sight

The Allen & Heath Qu-SB is a surface-less, rackmountable digital mixer that delivers the complete Qu-series mixing experience with no physical control surface at all. Every fader, EQ curve and effect is driven from a tablet running the Qu-Pad app, which turns the box itself into a compact 18-in/14-out audio engine that hides in a rack or under a stage. This is the mixer for engineers who have run out of room, weight allowance or sightlines for a full console but refuse to give up processing power. It is roadworthy, quiet and small enough to disappear into a flightcase, yet it carries the same audio brain as its faders-and-knobs siblings. Buy it once and it becomes the invisible heart of a rig you can mix from anywhere in the room.

What Surface-Less Mixing Actually Means

Surface-less mixing separates the audio processing hardware from the control interface, so the Qu-SB does all the analog-to-digital conversion, DSP and routing while your tablet supplies the buttons and faders over Wi-Fi. In practice you connect the Qu-SB to a wireless router, launch Qu-Pad on an iPad, and mix from the stage, the balcony or the middle of the audience where the sound actually is. Because the control lives in software, one engineer can walk a room and set monitor levels standing next to each performer. The Qu-You app extends the same idea to musicians, letting each player dial in a personal monitor mix from their own device. Removing the surface does not remove capability, it relocates it to wherever you happen to be standing.

Sixteen AnalogiQ Preamps With Total Recall

The front end is built on 16 recallable AnalogiQ mic/line preamps, the same digitally-controlled analog gain stage used across the Qu range. Total recall means the preamp gain is stored inside every scene, so recalling a saved show snaps all 16 inputs back to their exact settings rather than leaving you to reset knobs by ear. That matters most for houses of worship and multi-band venues that reset the entire console between services or acts. The combo XLR/TRS sockets accept microphones and line sources interchangeably, and switchable 48V phantom power feeds condenser mics and active DI boxes. Clean, quiet preamps at the input are what let the rest of the signal chain do its job, and these are widely praised as strong performers for the class.

The Same 32-Channel Engine as the Flagship Qu-32

Inside the Qu-SB sits the same 32-channel DSP mix engine found in the flagship Qu-32, running on a 5-core ARM processor. That shared architecture is the whole point: you are not buying a stripped-down budget engine, you are buying the top-tier Qu brain in a smaller, cheaper package. Thirty-two input channels feed a 48 kHz, 24-bit signal path with the headroom and low latency live sound demands. Because the processing is identical to the range-topping model, shows built on a Qu-SB translate directly to any other Qu console. It is a case of paying for the interface you need while keeping the performance you cannot compromise on.

Full Onboard Processing Plus RackExtra FX

Every one of the Qu-SB's channels carries a complete processing strip: a 4-band parametric EQ, a gate and a compressor, all adjustable from the app with the same precision you would expect on a physical desk. On top of the per-channel dynamics, the RackExtra FX rack supplies studio-grade reverbs, delays and modulation effects on dedicated returns. This means a single Qu-SB can EQ a drum kit, gate a noisy stage, compress a lead vocal and print a lush hall reverb without a single outboard box. For a portable rig, eliminating racks of external processors is a decisive weight and setup-time saving. The processing is deep enough that most engineers never reach for anything external.

Twelve Mixes, Four Groups and Two Matrix Outputs

Output flexibility is where the Qu-SB earns its place in complex rooms: it offers 12 mixes made up of 4 mono aux, 3 stereo aux and the main LR, plus 4 stereo groups and 2 stereo matrix outputs. That structure lets you feed multiple wedge and in-ear monitor mixes, drive delay towers or fill zones, and send a clean, separately-processed feed to a broadcast truck or lobby all at once. Groups let you ride a whole submix, such as all the drums, on a single control, while the matrix builds custom blends of those groups for distributed systems. For a box this small, the routing depth is genuinely console-grade. It is the difference between a mixer that just handles a band and one that runs an entire event.

Expandable I/O and Multitrack USB Recording

The Qu-SB is not locked to its onboard sockets: its dSNAKE and SLink port lets you push the input count up to 32 by adding optional AudioRack stageboxes over a single Cat5 cable, so a growing venue never outgrows the mixer. On the recording side, the built-in USB interface streams multitrack audio to and from a hard drive for gig capture and virtual soundchecks, and streams to a Mac or PC for a DAW. That USB recording turns any show into a multitrack session you can remix later or use to line-check the next day without the band present. Combined with expansion, it makes the Qu-SB a system that scales with the room and the workflow. You are buying a platform, not a dead-end.

Who the Qu-SB Is For

The Qu-SB lands naturally in houses of worship, small-venue live sound, corporate AV, portable PA rigs and bands who mix themselves from the stage or floor. First-timers get a genuinely approachable app that hides the complexity until they need it, while experienced engineers get total-recall preamps and console-grade routing in a bag they can carry with one hand. Anyone comparing it to a full-surface Qu console should weigh whether they need physical faders more than they need portability and price, because the audio engine is the same either way. It is roadworthy, reliable and reviewed as excellent value within the Qu ecosystem. For a rig that has to be powerful, small and mixable from anywhere in the room, the Qu-SB is the obvious answer.