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Allen & Heath MixWizard WZ3 16:2

Analogue Mixer
Published November 2004
By Tom Flint

Allen & Heath WZ316:2Photo: Mike Cameron

Allen & Heath's Mix Wizard range of multi-purpose analogue mixers has just been redesigned and re-released. But is the old magic is still there?

The Mix Wizard 3 family, comprising the WZ316:2, WZ312:2, WZ314:4:2, and WZ320S models, are multipurpose mixers blessed with feature sets that cater for both studio and live applications. If the name Mix Wizard sounds familiar, it is because Allen & Heath have previously manufactured two generations of Mix Wizards, and what we have here for review is version number three.

The original WZ16:2 was released way back in 1997, and just over a year later the improved DX version appeared. Since then, Allen & Heath have continued developing their professional live mixing consoles, and established a new range of DJ-friendly products, but what happened to the Mix Wizards? Stiff competition from programmable digital mixers, computer-based mixing software and budget-priced hardware may well have damaged the company's confidence in the studio market. Nevertheless, the demand for analogue studio gear has never gone away, and many people with software studios happily use analogue preamps and EQs in conjunction with their digital equipment.

The News

Anyone who has used or seen one of the previous generations of this mixer will recognise it immediately; it shares the same layout and colour scheme as its predecessors, and its overall feature set is very similar. Nevertheless, the circuits have been completely redesigned to incorporate newly available components and to take advantage of improved manufacturing methods. Separate circuit boards are still given to each of the mixer's channels, but they are produced using surfacemount manufacturing, which makes assembly easier, faster, and (no doubt) cheaper, and the resulting circuits apparently offer an improved performance due to their better noise rejection.

While redesigning the circuits, Allen & Heath took the opportunity to modify the feature set, basing their changes on several years of user feedback. Some modifications clearly benefit the live engineer most: a socket for connecting a gooseneck lamp is most needed in darkened venues, for example, and the inclusion of a connector for use with a second power supply, configured so it kicks into action if the main source fails, is something worry-prone live engineers will welcome.

The redesign also includes a number of minor improvements, including things such as extra rubber feet on the connector pod for when you're using the mixer on a desktop, and moulded plastic side trims, the latter largely added for aesthetic reasons, as far as I can see. Details like these are nice, but there is a batch of far more significant improvements on offer too. Just like its predecessors, the WZ316:2 fits into a standard 19-inch rack, once its plastic end cheeks have been removed, so there is limited front-panel space for adding new features. Nevertheless, the designers have managed to squeeze in some physical additions, the most obvious of which is a black fader labelled 'M', situated next to the 'L' and 'R' (left and right) master channel faders. In this instance, 'M' is a mono channel which has its own balanced XLR output on the rear panel. The channel can be fed either a summed version of the left and right channels or the signal from the Aux 6 buss. A tiny blue recessed button nearby allows the selection of one or the other. The 'M' channel could be used in a number of ways, and is best thought of as a flexible buss with its own level control.

With the aid of a screwdriver it's possible to re-configure the mixer for rackmount use, rotating the connector pod through 90 degrees and exposing the rack ears by removing the plastic side trims.With the aid of a screwdriver it's possible to re-configure the mixer for rackmount use, rotating the connector pod through 90 degrees and exposing the rack ears by removing the plastic side trims.Photo: Mike Cameron

Perhaps most welcome of all the mixer's improvements is the introduction of independent phantom-power switching on all 16 mixer channels. The DX had just the one switch governing the delivery of phantom power to all its channels, which might have been restrictive for anyone wanting to use a mixture of dynamic and condenser mics. I still think that it would have been better if Allen & Heath had used phantom-power buttons of the transparent LED-lit type though, so that their status was totally clear at a glance.

Less obvious to the eye are a number of customisation options offered by jumper switches located on circuit boards inside the mixer casing. (See the 'Jumping Inside' box for a full listing of these options.) These are largely intended as semi-permanent customisation options that the user will set up to suit their way of working, but will thereafter rarely touch. In the past the Mix Wizard's custom options required the cutting of certain resistors, or the insertion of various ICs into specific parts of the circuit, and for one particular customisation shown in the manual this is still what you have to do. However, the use of jumpers is a much better idea, as it is easily reversible.

The 16:2 also provides a few new effects-routing options by way of four knobs situated in the master section, labelled Aux 1, 2, 3, and 4. These are dedicated send controls for delivering the feed from the internal effects (more on the effects later) to the first four auxiliary outputs, presumably so that any stage monitors hooked up to the aux sends can receive independent effect mixes. As standard, the internal stereo effects are sent in mono to each of the four Aux sends, although one of the internal options allows the effects to be sent in stereo to odd-even pairs.

The other main additions to the WZ316:2 include a footswitch input for muting the effects return channel, and a back-panel slot for the installation of a Sys-Link II board. Once fitted, the optional board allows the desk to be connected to the four-buss WZ314:4:2 or to some of the larger Allen & Heath mixers, where it acts as an input expander with linked auxes and synchronised PFL control.

Allen & Heath mixers have often been praised for their sound quality, so I was interested to read that the WZ3 range has been given a new preamp design and has altered EQ settings. As it turns out, the EQ's high and low shelving filters have been adjusted so that they are more responsive at the important frequencies of 10kHz and 100Hz respectively. The preamps have received a slightly more radical reworking. Firstly the gain range has been increased by 10dB, so that the preamps provide 10-60dB of gain instead of 20-60dB, and in the process the gain law on the potentiometer has been optimised so that better use is made of the sweep of the pot. At the same time, the 30dB pad of old has been reduced to a 20dB pad, so that up to 40dB gain is available when the pad is selected.

The Big Picture

Having discussed the new features on offer, let's have a more general look at this new Mix Wizard. All sixteen of the WZ3's input channels are identical, unless a channel is re-configured via the internal jumpers. Signals enter a channel through either a balanced XLR or balanced quarter-inch jack input socket situated on the back panel. Each channel has its own insert point and direct output courtesy of two further jack sockets. After the aforementioned preamp, each channel has a high-pass filter switch attenuating at 12dB/octave below 80Hz, and operating just before the insert point. Next comes the four-band EQ, followed by six auxiliary sends. At the base of the channel is a pan knob, a channel mute switch, a pre-fader monitoring switch, and a smooth 100mm fader.

Allen & Heath WZ316:2Photo: Mike Cameron

All of the WZ3's connectors are situated on the back panel, apart from the fixing for the goose-neck lamp and the headphone socket, both of which are on the front panel. The connector panel is on a hinged section of the mixer, which can be rotated from 90 to 180 degrees relative to the front panel once two fixing screws are removed. In its 90-degree position, the chassis acts as a stand for the mixer, tilting it up towards the engineer. When it's folded back at 180 degrees, the mixer can be installed in a rack more easily.

Besides the channel inputs, insert points, and direct outputs already mentioned, there is a row of six jack sockets for the aux send outputs. When these are used to send signals out to effects, the returning signal can be plugged into either one of the two pairs of jack sockets labelled ST1 and ST2, although the unbalanced ST2 is partly intended as an audio input for a device playing pre-recorded interval music during live shows. These inputs are situated next to a pair of impedance-balanced outputs marked AB, which offer an alternative version of the stereo mix and are intended for sending a signal to an external stereo recorder. Just below the AB outs is a blanking panel where the Sys-Link II option can be added.

The remaining inputs include a single MIDI input for editing the internal effects, the footswitch jack input, the DC input for connection to a backup power adaptor, plus a pair of insert jacks specifically for the stereo master channel. The remaining connectors not yet mentioned are the three outputs for the left and right channels and the new mono master channel, and these are provided by balanced XLRs.This Sys-Link II card can be inserted behind the blanking panel at the bottom right-hand side of the mixer's back panel. Once installed, the WZ316:2 can act as an input expander module for the WZ314:4:2 or a variety of Allen & Heath's larger mixers.This Sys-Link II card can be inserted behind the blanking panel at the bottom right-hand side of the mixer's back panel. Once installed, the WZ316:2 can act as an input expander module for the WZ314:4:2 or a variety of Allen & Heath's larger mixers.Photo: Mike Cameron

Aux Sends & Effects

The WZ3 has six mono auxiliary sends available to each channel. Aux 1 and Aux 2 are pre-fader, which is fairly standard on desks used for live work — these auxiliary busses can then be used to feed stage monitors and wedges, and their level settings will remain independent of the main mix. These aux busses are also fed from a point before the insert and the EQ, although this can be changed independently for each channel by moving certain of the circuit-board jumpers. Aux 3 and Aux 4 can be switched pre/post-fader via a front-panel button, whereas Aux 5 and Aux 6 are post fader, and are routed to the internal effects as standard.

In the mixer's master section six auxiliary master controls allow overall buss level adjustment, and next to these are a set of switches which determine which auxiliaries can be heard through the monitoring channel. By selecting the relevant buttons, the engineer can monitor single auxes, pairs of auxes (by pressing the appropriate buttons together), and also the activity of the ST1 and ST2 channels. The onboard effects, which we'll detail a little later, are routed so that they receive signals from Aux 5 as standard, although when the Dual FX mode is selected, and both effects processors are activated, the second receives the Aux 6 signals. A master level pot labelled ST1/FX Lev returns the combined effects to the LR mix. As mentioned earlier, four further aux send controls deliver the effects to the first four aux busses. The level of these sends is unaffected by the ST1 control, so the effect feed to the mix remains separate. The pair of ST1 jack inputs are intended to handle the input from external effects devices. These too are routed to the main LR mix buss via the ST1/FX Lev control.

There are three more knobs in the master section which I haven't yet mentioned. The most obvious is the headphone level control with its own PFL LED indicating its mode. Elsewhere is the ST2 Lev knob with an associated switch which routes anything plugged into the rear-panel's ST2 inputs to the main LR mix buss. The last knob controls the level of the AB output. The control has its own recessed mini-switch so that the LR output or the monitor signal can be output through the rear AB output jacks as required.

EQ & Preamps

As demonstrated by the lengthy listing of features above, the WZ316:2 has a lot to offer, but nothing that would count for very much if its EQ and preamps were poor. Earlier we discussed the redesign of both, but the question of how they actually perform remains. Firstly, a brief run-down of the EQ components: there are high and low shelving filters, as well as two sweepable mid-bands. The high shelving filter provides ±15dB/octave above 12kHz and the low filter operates below 80Hz, although both filters actually begin working somewhere close to 1kHz, their response curves becoming steeper as they move towards the frequency extremes, as well as acting more vigorously than before at 100Hz and 10kHz.

The lower mid-band filter offers 15dB of cut or boost centred anywhere from 1kHz down to 35Hz. The upper mid-band can also be swept, this time from the overlapping value of 500Hz all the way up to 15kHz. Modern digital EQs offer variable Q settings which allow EQ bands to be focussed precisely on certain troublesome frequencies, but without that option an analogue mixer has to provide a fixed Q that works for all occasions. The setting of 1.8 offered by both mid-bands is a good, effective choice which sounds natural even with extreme processing.

Four bands of EQ is generous — many similar-sized analogue mixers only offer three — but the most important thing is that these filters are good enough to be used liberally without fear of making a sound appear unnaturally affected. However, I also wish there was an EQ bypass switch so that radical EQ settings could quickly be compared with the unprocessed signal.

The sixteen preamps are impressively quiet. I didn't have a previous-generation Mix Wizard to hand, so I couldn't check whether the surfacemount technology, or indeed the optimised gain law, had improved matters, but the new design certainly compared favourably with other preamps I have used in recent years, and it's hard to imagine how much better even the very best preamps could possibly be.

They're perhaps not quite as kind to an input signal as the preamp in my TL Audio 5051 voice channel, but, at the same time, they appeared to be slightly quieter. They are certainly much quieter than those in my Yamaha AW4416, which, admittedly, is not renowned for the quality of its preamps. In a side-by-side subjective listening test with a Behringer Eurorack MX1602A, which boasts the same ultra-low-noise preamps as the top-of-the-range MX9000, the WZ316:2 fared pretty well. At 60dB gain, the two products exhibited similar levels of noise, which, in practice, were vanishingly low compared to any reasonable audio signal. Subjectively, the Mix Wizard seemed to me to have a slightly warmer sound, although the differences were hard to detect on most material.

Jumping Inside

Here you can see the internal construction of the mixer, using individual circuit boards for each channel. The inset on the left shows the IC sockets which can be used to alter the balancing properties of the auxiliary outputs. Jumpers on each channel, shown in more detail in the right-hand inset, can be re-configured to alter the characteristics of the aux sends and direct outputs.Here you can see the internal construction of the mixer, using individual circuit boards for each channel. The inset on the left shows the IC sockets which can be used to alter the balancing properties of the auxiliary outputs. Jumpers on each channel, shown in more detail in the right-hand inset, can be re-configured to alter the characteristics of the aux sends and direct outputs.Photo: Mike Cameron

After removing the metal panel which covers the underside of the WZ316:2, it is possible to change some of the mixer's settings by moving various jumper switches located on the circuit boards. Things aren't completely straightforward, however, because you need a Torx star-head key to get inside, and the manual's diagrams, while clear, aren't always easy to relate to the actual mixer internals. Each of the 16 channel boards has 13 sets of pins, six of which already have jumpers across them. The jumpers themselves are small plastic caps containing a conductive bridge. Moving jumpers is simply a matter of sliding them off one set of pins and replacing them on another. I say simple, but it is quite fiddly getting between the boards and grasping the jumpers, and easy to drop them into the bowels of the mixer by mistake — I'm sure anyone wanting to change the settings for all channels would find the job extremely frustrating!

The first two jumpers serve the pre-fade auxes, and configure Aux 1 and Aux 2 so that they are fed from a point after the equaliser. The next two jumpers switch the position of the direct outputs from pre-fader to post-fader. The remaining eight jumpers govern the pre/post-fader status of the six auxiliary sends. At one extreme, all auxes can be made pre-fader, while another patching scheme would turn all six into post-fader mode. It's also possible to have any of the auxes change its position under the control of the front-panel switch.

The inner of the two boards serving the mixer's master section contains a set of IC sockets relating to the six auxiliary channels. By snipping the legs of a set of resistors and then inserting the correct IC components into the sockets (the ICs are not supplied as standard), the mixer's auxes can be changed from their default impedance-balanced condition, operating at -2dBu, to an electronically-balanced condition with a +4dBu nominal level. The manual is clear on how to insert the ICs, which type can be used, and which resistors need to be cut, although it labels the sockets from U7 to U12 for some reason, and no such labelling was apparent on my review model. I even opened up the connector panel just to double check I wasn't supposed to be looking at a different set of sockets!

The outer board of the master section holds the four jumper plugs required for changing the AB output source from the factory post-fader setting to a pre-fader one. Allen & Heath quite reasonably suggest the pre-fader setting be used when the AB outs are feeding a tape with its own level control, or a similarly remotely attenuated broadcast feed.

The last option offered by the WZ316:2 is a switch for changing the status of the ST1 stereo return signal, which by default is summed into a mono signal and then fed to the monitor channel's four aux feeds. Moving the jumper diverts the left signal to Aux 1 and Aux 3 and the right signal to Aux 2 and Aux 4. After some scrutiny of the diagram I found the jumper on the inner board of the master section hiding under two capacitors. Reaching it from the side is impossible due to the protruding hinge of the Pod, and I'm not sure how anyone would be able to see the position of the jumper clearly without taking the mixer apart. Moving this jumper shouldn't be attempted without some needle-nosed pliers and one of those mirrors on a stem used by dentists for studying the back of someone's teeth!

Internal Effects

As mentioned above, the Mix Wizard offers its own internal effects processor which works in Single FX or Dual FX modes depending on the status of a small blue recessed switch under the aux master controls. In Single FX mode, there are 16 effects available, split into two banks of eight. Of the sixteen, half are reverb variations, while the rest are a selection of delays, choruses, and combination effects. In Dual FX mode, the first eight effects, which are mostly reverbs, are fed from Aux 5, leaving the second batch of reverbs, delays, choruses, and phasing effects to Aux 6.

Annoyingly, the only way to turn the internal effects off is by scrolling to an 'off' position at the end of the effects bank. More irritating still, the effects turn themselves on every time you change between Single FX and Dual FX mode. The ST1/FX Mute button does mute the effects, as does a pedal switch, but it also mutes any external effects signal input via the ST1 jacks. Why not include a switch for just the internal effects for when only external effects are required?

The internal set of reverbs and ambience settings are well chosen, and balancing the channel send with the master aux return level provides enough control for most applications. According to Allen & Heath's chief designer, the factory presets were chosen to 'provide general-purpose reverbs and delays as a starting point for live mixing'. However, ironically, their emulations of live acoustic spaces actually make them quite useful for adding a live effect to studio recordings!

The delays are more problematic, however, as there is no way to adjust delay time without using software. Should you wish to edit the delay time, the internal effects parameters can be accessed by hooking the mixer up to a sequencer's MIDI port and then using Allen & Heath's freely downloadable software (available on their web site) to do so. There can't be too many live engineers who will want to have on their mixer hooked up to a PC just to tweak effects, although someone with a MIDI-enabled laptop could easily do so. Studio musicians might be a little more accommodating, but I really can't see why anyone should have to resort to using computer software to operate a stand-alone piece of hardware such as this. Way back in 1998 I used a Studiomaster Vision 8 powered mixer for a series of live gigs. Its effects section offered memory options, EQ, and, most importantly of all, it had a fader allowing the immediate adjustment of the effect's delay time. Even though the Mix Wizard has no room for such a fader, delay time could still be controlled via a hardware tap-tempo button, as found on numerous effects processors.

In terms of sound quality, the internal effects are comparable to those in my respectable Lexicon MPX100, which I ran through the ST1 input during testing. In fact, the algorithms are the same Digitech-supplied ones as used in the previous DX model, although Allen & Heath say that the WZ316:2's improved hardware and converter circuits make better use of the effects than before.

Allen & Heath WZ316:2Photo: Mike Cameron

In Conclusion

After looking closely at this product and studying the manual, I really get the feeling that Allen & Heath have aimed the Mix Wizard at the live market first and the studio market second. Nevertheless, the WZ316:2 is the sort of hardware a lot of project studio owners still desire. Even though just about all digital workstations have their own preamps and mixers, and computer sequencers all come with mixing facilities as standard, many people will want to use the Mix Wizard's low-noise preamps and EQ as a front end for their digital recorders, or before sending signals to their computer soundcards. The sixteen direct outputs make this eminently possible, and having inserts on all the channels also allows analogue compressors or gates to be inserted into the signal path. This is particularly desirable when recording a large drum kit, for example. Others may choose to use the WZ3 for mixdown, inserting a mastering compressor into the main LR channels.

The internal effects are disappointing in their implementation, even though their actual sound quality is fine. Allen & Heath were clearly running out of front-panel space with the rack design, but offering editing via a computer seems like a cop-out. The strength of such a piece of hardware lies in its independence from computer software, and the addition of just a few controls would allow the WZ3 to stand strong on its own.

With so many customisation options and such an array of input and output options, the WZ316:2 is extremely flexible. Even without the jumpers, there are enough well-chosen front-panel adjustments to be getting on with. For example, the combination of AB and 'M' outputs, ST1 and ST2 inputs, and the various switching options allow the mixer's facilities to be divided up and used in quite a number of ways. Having so many options means that the WZ316:2 can be adapted to suit the needs of a developing studio or venue, and the Sys-Link II option offers the potential for expanding the system in the future.

Inevitably, some people will flinch at the price, and point out that there are other mixers in the UK market with a roughly similar collection of basic features selling for a lot less — Soundcraft, Mackie, and Behringer all offer such products, for example. However, at the end of the day, with an Allen & Heath mixer you get what you pay for. I'm sure the company could knock a lot off the price of this mixer if they just used one large circuit board for all the channels' circuitry and control knobs, and mounted it parallel with the control surface — that is certainly what some cheaper mixers look like inside. But the WZ316:2 has a separate board for each channel and instead of having the control knobs mounted on the circuit board so that they poke through the mixer's metalwork, all the controls are firmly bolted to the front panel. Any knocks the controls receive will be taken by the metal casing and won't flex the more fragile circuit boards. In fact, wiggling the pots reveals that they have hardly any play compared to circuit-board-fixed pots which tend to flex like joysticks!

It's nice to know that if you decide to keep the mixer for many years, noisy pots and faders can be replaced one channel at a time, rather than having to replace the whole board. In that respect, the 16:2 is best thought of as 16 channel strips plus a master section, and in those terms the asking price doesn't sound unreasonable at all.

Published November 2004