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Allen & Heath Mixwizard 20:8:2

Mixer By Martin Walker
Published September 1997

After a spell away from project studio consoles, Allen & Heath return with a magical new contender. Martin Walker conjures up some thoughts on the WZ20:8:2.

Allen & Heath must have a big cauldron. Only a few months ago, the new MixWizard range was launched with the arrival of the WZ16:2, which, as its name suggests, is a 16:2 mixer primarily intended for stereo recording, front of house, on‑stage sub‑mixing, or fixed auditorium sound systems. (I reviewed this for our sister title Sound On Stage, June '97 issue, so if you think it would be suitable for you, phone the SOS mail order department for a back issue.) The unit under review here has a more advanced spec for 8‑track use, with eight mono mic/line channels, six stereo line channels, and eight mono tape channels, giving a total of 28 inputs at mixdown. This will be most SOS readers' first sighting of the range, so a bit of background information is in order...

So many small mixers vie for attention in the marketplace that the only ones that really get noticed are those offering something genuinely different. In the case of the MixWizard range, its main claim to fame is that, despite its low price‑point, it features six independent aux sends, and an advanced EQ section with two swept mid controls. These certainly make it stand out from the crowd. The range also shares some of its features and components with the much higher‑priced GL4000 series of live desks, and, like them, it's designed and built in Britain.

Just In Case

Both models in the MixWizard series have the same basic casing — a cool ocean‑blue steel 10U rack unit whose front panel has integral 'ears' for maximum strength. It features what Allen & Heath call the quick‑change connector (QCC) system, which is a variant on the Mackie rotating patchbay pod. This has two positions, allowing the input/output socket panel to be placed either behind the mixer (normally used when rack mounting, so it is 'inside' the rack), or at right angles to the front panel as a supporting leg (for desktop use). On the desktop, the front panel is angled at 15 degrees from horizontal. Changing between the two positions is very easy, with only a single screw each side of the mixer to be removed before you can swivel it to the new position and pop the same two screws back again. It would have been useful to have an additional position for desktop use with the sockets ending up at the front, extending the front panel, but Allen & Heath say that this would have involved "exposing the innards".

As always, design decisions have to be made, and giving the Wizards a smaller footprint means that they've both ended up with longer legs (in desktop mode, their maximum height is 7.5 inches). However, with a mixer of this size it's not too difficult to lean over for re‑patching, and if you need to do this regularly a separate patchbay might be in order anyway.

This is a little desk that can do a lot, with the minimum of fuss and a surprising amount of flexibility.

The rugged nature of the WZ20:8:2 is further revealed by the fact that each rotary control is individually bolted to the front panel, which ensures that they all have a smooth action. The alternative is to let only the spindles of the pots protrude through holes in the front panel — this can result in stiffness, scraping, loose wobbly controls, or, in bad cases, all of these! The main reason that Allen & Heath can (and must) bolt the controls individually is that each channel is on a separate circuit board. This is good news indeed, as it makes servicing (at some very remote time in the future, you hope) far easier. Finally, since this is such a contentious issue I'll not make you wait until later to find out — the case does have room for a built‑in power supply, so there's no wall‑wart to lose.

Tearing Off A Strip

The first eight channel strips are intended for mic/line use (although they come in very useful later for mixdown purposes). Before we start at the top of the controls, it's worth mentioning a neat twist with the input sockets. As you might expect, both balanced XLR and balanced TRS jack sockets are provided, but rather than tying the XLR to mic duty, and the jack to line purposes, Allen & Heath have sensibly allowed both sockets to serve for either. The only distinction between them is that the XLR is also wired for 48V phantom operation. This means that you can plug in a mic‑ or line‑level signal using balanced or unbalanced XLR cables, or balanced or unbalanced jack leads, which should result in fewer people having to resort to using in‑line adapters to plug in rogue equipment.

As always, a pad heads up the channel strip — in this case 30dB. The rotary Gain control ranges from 60 to 20dB (pad out), and 30 to ‑10dB (pad in). At this point, an Insert emerges on the back panel with the standard TRS (Tip, Ring, Sleeve) arrangement, at 0dBu level. The next section contains the EQ, and here there are two small changes from the 16:2 model, which put the 20:8:2 more into studio territory. The 100Hz 'rumble' filter of the live model disappears, but at the bottom of the EQ section an additional EQ In/Out switch appears instead — for comparison purposes this is a godsend. The basic LF and HF shelving controls are tuned to 60Hz and 12kHz, which nowadays are fairly standard frequencies, providing plenty of control without ever becoming unduly harsh. The mid controls are in two sweepable sections. The higher one (MF1) has a frequency range of 500Hz to 15kHz (with a central position of 3kHz), and the lower one (MF2) goes from 1kHz right down to 35Hz (the central value is 180Hz). These two, in conjunction with the LF and HF, provide a versatile system that can be creative or corrective. All four bands have a ±15dB range. Although the mids have a fairly low quoted Q of 1.9 (about one‑octave bandwidth), this is still sufficiently narrow to 'dial in' to the most active part of a sound.

Below the EQ section are no less than six Aux sends, although Allen & Heath refer to the first two as Cue 1 and Cue 2, as they are pre‑fader, and will often be used for foldback purposes. Aux 3 and 4 are switchable pre‑ or post‑fader as a pair, and Aux 5 and 6 are dedicated post‑fader sends. The bottom section of the strip comprises Pan, a channel on/off button, a latching PFL switch, a peak LED that comes on 5dB below clipping (and which doubles as a PFL indicator), and a full 100mm fader, which has a smooth, low‑friction travel. To the left of the channel fader are five routing buttons: L‑R, 1‑2, 3‑4, 5‑6, and 7‑8.

The Best Of The Rest

The six stereo channels (channels 9‑20) are rather simplified by comparison. A pair of unbalanced jack inputs is provided, with the left one doubling for mono purposes if needed. After a switched ‑10/+4 sensitivity switch comes a basic 2‑band EQ, providing the same turnovers of 60Hz and 12kHz as the mono channels. The Aux sends provide a neat twist — Cues 1 and 2 are combined onto a single control, providing a stereo feed, although this won't reflect any setting of the Pan control other than 'central', since it's earlier in the circuit. Aux 3 and 4 are also combined into a single control, with a pre‑post switch; Aux 5 and Aux 6 are separate controls. The final fader and panpot section is exactly the same as for the mono channels.

The mono channels have excellent EQ and are one of the main selling features of this desk.

Above the stereo channels are the eight Tape Returns, and these are fairly simple, featuring a combined Cue 1‑2 control (this time post‑pan), an Aux 6 send, Pan, and a Rotary level control and associated PFL switch. At the bottom of this area, each Tape Return has a Tape Rev switch, which swaps the tape return signal with the equivalently numbered mono channel (post Gain/pre Insert). This allows the signal coming off tape to be sent through the more complex 4‑band EQ and six sends of the main channel strip, while the mono input signal is re‑routed to the simplified controls provided by the Tape Return section. Below the Tape Returns is the Mixdown switch — this globally overrides the individual Tape Rev switches, as well as automatically routing all eight tape signals to L‑R outputs, and bypassing the Channel On switches. This gives an easy way to reconfigure the desk, and saves having to re‑route all eight channels by hand — a neat time‑saving feature.

The Output Master and Monitor section is fairly simple. From the top down, there's a recessed switch (use a biro), providing global 48V phantom power for the mono channels, followed by a single pair of 12‑segment LED ladder array meters. These default to showing L‑R signal level, but can also monitor PFL (pressing any channel PFL button illuminates a large red LED as well as the small one next to the appropriate PFL button). There are also six buttons with top‑down priority. Next most important to PFL is Cue 1‑2, then Aux 3‑4, followed by Aux 5, Aux 6, 2Tk‑1, and 2Tk‑2. The last two monitor the signals coming from two supported stereo recorders, whose inputs are also connected to the L‑R busses (see the 'What's Around The Back?' box).

Having 28 inputs available makes this a very useful mixer for many recording setups...

To the left of the monitor switches are the Aux Masters — four rotary controls for Cue 1‑2, Aux 3‑4, Aux 5, and Aux 6. Beneath these is a mono button (always useful for checking mixes), and a rotary Monitor Level control, which feeds both headphone and monitor outputs. I preferred the separate level controls for phones and monitor found on the WZ16:2 model, but there's only so much space on the front panel. The Phones socket itself is to the left of this, and there's also a recessed switch that changes phones from normal monitoring duties to Cue 1‑2, which is a useful way to provide musicians with a stereo cue signal while the monitor outputs still listen to the main mix. Finally, there's a small clutch of controls for Talkback purposes — a screwdriver‑adjusted level‑trim rotary control, and an L‑R slate button that lets you talk to your stereo recorder machine for ident purposes. A 1‑8 slate performs the same function for your 8‑track machine, and the Talk to Cue button connects the mic to the Cue 1‑2 mix (in all cases, the main monitor mix is attenuated to prevent feedback). The final button is another recessed one, and this provides a 1kHz tone that's routed to channel 8 (pre‑insert) — by doing this, rather than sending it direct to the L‑R outputs, you can route it to any Aux send or any of the output channels, for a comprehensive line‑up.

Testing 20, 8, 2

All the controls are smooth and positive (one of the benefits of bolting each rotary to the front panel is a consistent feel), and the long‑throw faders work very nicely — although the stereo channels do seem to have slightly more mechanical resistance than the others, this is marginal. Ergonomics are good, with sensible use of knob colours and clear pointer indications, but one of the difficulties of cramming such a lot of mixer into a 19‑inch rack width is that everything ends up so close together. Although the mono channel spacing (about an inch) is the same as on the WZ16:2 stereo desk, with the added routing buttons in place two things happen. First, the fader markings between ‑10 and +10dB end up obscured by the fader caps themselves, which makes it tricky to position the faders accurately around the 0dB setting. Second, with two adjacent faders set at typical 0dB positions, it's difficult to reach the buttons between them unless you have slim fingers. My hands are not large, but only my two smallest fingers were narrow enough to operate the buttons in this situation. This problem does not arise with the stereo channels, as the spacing here is 1.25 inches — even an extra quarter of an inch makes a lot of difference!

The mono channels have excellent EQ (see the 'Listen Here' box and the screenshot), and are one of the main selling features of this desk. I also liked the fact that the stereo channels, although they have greatly simplified EQ, keep the same 60Hz and 12kHz turnover frequencies. So many manufacturers change to coarser frequencies such as 100Hz and 10kHz; while this gives more radical control, it can often end up sounding harsh by comparison. I did find the Cue 1/2 system a little confusing, since it's obviously intended as a single stereo Cue with both the Tape Returns (post‑Pan) and the Stereo inputs (pre‑Pan). However, it still appears as two separate controls for the mono channels, which makes setting up foldback a little more thought‑provoking.


The extra £160 on top of the WZ16:2's price gives you an extra eight inputs, 8‑buss routing, a 1kHz line‑up oscillator, and talkback, as well as the Mixdown button, which allows every multitrack channel to be automatically re‑routed to a full 4‑band EQ channel strip. Having 28 inputs available in total makes this a very useful mixer for many recording setups, with, arguably, the right balance between mono and stereo channels — even with eight tracks recorded, you still have enough stereo inputs to hear a clutch of synths and effects units, during both recording and mixdown. Although there are no metering or faders for the 8‑track outputs, most people will have their eyes firmly glued to their ADAT (or equivalent) meters, since digital recording is so unforgiving of overload.

This is a little desk that can do a lot, with the minimum of fuss and a surprising amount of flexibility. You couldn't cram much more into a standard rack width and still operate it comfortably, and if you want this much mixer to fit in a rack, the Wizard 20:8:2 is well worth a look. It's excellent value for money, and should suit many musicians' requirements.

Getting The Hump

As a little experiment, I plotted a few EQ frequency responses using Sound Forge and a PC soundcard to show just what is possible with the WZ20:8:2's EQ section. The upper plot shows the response with LF at +15dB, MF1 at 180Hz and +9dB, MF2 at 3kHz and +12dB, and finally HF at +15dB (the classic four‑hump tone‑control curve of a typical EQ). The middle trace shows the same settings for LF and HF, but with both mid controls put 'out of circuit', by setting them to 0dB. The lower trace shows one example of what you can do with the EQ, by turning MF1 up to its highest 15kHz, and MF2 down to its lowest 35Hz, with both LF and HF at 0dB. As you can see, both bass and treble response curves show completely different shapes to the middle plot. Using all four bands in combination, far more versatility is possible.

Listen Here

However good the spec, the most important thing is what the unit sounds like. Allen & Heath make a play of their Minimum Signal Path (MSP) structure. Any audio signal will change slightly when sent through electronic circuitry, or even passed down a wire or through a plug‑and‑socket connection. Many of these changes are so small that the human ear will not detect them, but they are cumulative: after the signal has passed through an entire mixer, it will always have degraded slightly. You can improve transparency for the audio signal not only by using wide‑band low‑noise amplifiers, but also, as long as the remaining circuitry is not compromised, by removing any components directly in the signal path that are not needed, such as DC blocking capacitors between amplifiers where the design can be tweaked to remove the DC offset.

Whatever the theory, both of the MixWizard mixers I have reviewed have had a very detailed sound, which enables you to hear subtle details in the mix. Hearing the same music through the same well‑known system with just one component changed can be a revealing experience. Allen & Heath do seem to have succeeded in designing a mixer with a transparent sound, but which has the advantage of allowing you to change the sound in a radical way if you need to. The EQ does take a little more thought to use, but allows a much wider range of sounds to emerge at the other end. Although you can create speaker‑blowing combinations of 30dB cut and boost at spectrum extremes, you can also use the EQ in subtle ways — the 'small dip here, tiny hump there' approach. The only slight downside is that the wide frequency swings available on the two mid sweeps may make accurately re‑creating previous EQ settings just that little bit more difficult.

What's Round The Back?

On the rear panel, the first eight channels have both XLR and TRS jack input sockets, as detailed in the main text, along with an Insert, also on a TRS jack at 0dBu level. Phantom power is switchable on a global basis for the XLR inputs. The stereo inputs are on twin mono jack sockets (unbalanced), with the Left channel also doubling, as usual, for a mono input. The 8‑track Tape Inputs and Outputs are again on jacks: the inputs are unbalanced, with a useful global back panel switch that selects between ‑10/+4 levels, and the outputs are impedance balanced, wired to TRS jacks. The Aux sends (including Cue 1 and 2) emerge on impedance‑balanced TRS jacks at ‑2dBu (about 600mV RMS), which I presume is a compromise between ‑10 and +4 levels, allowing connection to a wider range of devices.

Two sets of L‑R connections are provided for stereo recorders. The first, '2TK‑1', has balanced XLR connectors at +4dBu level: a pair of male ones for outputs, and a female pair for the inputs. The second set is labelled '2TK‑2', and these are on TRS jacks at ‑10dBV (the outputs are balanced, but the inputs are only impedance balanced). A further pair of TRS jacks provides the L and R outputs with an insert point at ‑2dBu. The Talkback input (mono jack socket) is suitable for dynamic mics, and its sensitivity can be adjusted by a front‑panel trim control, from ‑50 to ‑20dBu. Finally, on the back panel, the built‑in mains power supply has an IEC socket, and a small on/off toggle switch.


  • Versatile 4‑band EQ.
  • Six separate sends.
  • Transparent wide‑band sound.
  • Excellent value.


  • No group faders or meters.
  • Poor visibility of fader markings on mono channels.
  • Phones and monitor outputs use same level control.


A lot of mixer for your money, and ideal for basic 8‑track setups (unless you have the hands of a gorilla). Sound quality is excellent, and the overall design is straightforward to use, without cutting too many corners.