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Allen & Heath GS3

Multitrack Mixer

With features enough for a low-end one-inch 24-track studio, and a price low enough for the top end of the quarter-inch 8-track market, Dave Lockwood finds the Allen & Heath GS3 too good to be ignored.

Think of all the features you would like to have on a compact multitrack desk in the sub-£2.5k bracket. Confining ourselves to those things which are economically feasible at this price, how about: an in-line monitor configuration, to get the maximum number of inputs in a given frame size, plus an expandable configuration so you can add channels later if you need to; a sophisticated MIDI muting system, which is available on all circuits, not just the main channels; a monitor channel which can be taken seriously as an extra input (it must have its own EQ and access to at least two auxiliaries, not counting any cue sends); and at least one of the monitor auxs must access the same bus as one of the channel sends.

We also want several stereo FX returns, and all the little extras such as integral talkback and an on-board oscillator — in fact, all the operational conveniences you would expect of a console costing twice as much. Well, Allen & Heath's GS3 has got all of these, plus something we probably wouldn't have thought of asking for: MIDI Function Keys, which can be programmed to transmit any MIDI messages you care to store. Remote control of a tape transport is one obvious application for this feature.


The GS3 is a further development of the S2 console, sharing the same basic constructional features, with a non-modular 16:8:2 in-line configuration which can be extended to a maximum of 32 channels using up to two further 8-input expander blocks. The structural aluminium extrusions which provide rigidity in the chassis are replaced by full-length pieces, allowing an expanded model to look like it was originally built that way. Expander modules are added on to the right-hand side of the chassis, allowing channel numbering to be continuous, and creating a balanced appearance with a central master section.

Given the impressive monitor channel facilities, and four stereo FX returns, a 16-input console, for once, really can be said to genuinely offer 40 usable inputs on mixdown, whilst a fully expanded 32-input unit offers 72 (32 inputs, 32 monitors, plus four stereo returns).

The entire operating surface is a single panel, with all connectors located in the same plane as the controls, in a strip along the top of the desk, keeping them within easy reach as a virtual patchbay. Full marks to Allen & Heath for moving the channel insert point jack to the front of the connector group; the inserts are the connections that will be re-plugged most often, whilst tape-returns/sends, mic cables, and inputs from MIDI instruments may well be semi-permanent. You can now get at the inserts with ease, making non-patchbay usage less of a handicap — other manufacturers with top-mounted connectors would do well to take note.

All inputs and outputs on the GS3 utilise unbalanced jacks, apart from the electronically balanced XLRs for the microphone circuits. Individually switchable 48V phantom is provided on each mic input. Nominal interface level is normally the semi-pro standard, -10dBV, matching all Tascam and Fostex narrow-gauge multitracks, although +4dBu operation is an option. Insert points, provided on all input channels, groups, and the stereo bus, are via the standard tip-send, ring-return, 3-pole jack system. (With monitors invariably now acting as extra mixing channels, can we expect to see inserts on these before long?). The freestanding external power supply connects to the desk via a multipin latching XLR, with fixed cables used for both mains input and PSU output. MIDI In, Out, and Thru sockets complete the connector line-up.


Signals enter the channel path via the Mic/Line selector switch, followed by the channel Gain control. Input Reverse is available, to swap the line input with the monitor's normal tape-return input — this is the configuration you would use for employing the monitors as extra inputs during a mix (assuming you want to mix the tape signals via the channels). The gain control stays with the channel, and is therefore active on the tape signal when mixing, allowing fader range, and mixing headroom, to be optimised for actual (as opposed to ideal) levels on tape. The channel input amp has gain to spare, and a healthy overload margin; in spite of the absence of a Pad facility, I experienced no front-end problems in typical usage.


The GS3's channel equaliser offers two 'sweep' stages, with a fixed-frequency, shelving HF control. Compared to the S2's nominal 16kHz, the HF has been moved to an altogether more useful 12kHz, providing 14dB of cut or boost. The upper sweep mid control also extends to 12kHz, but with a peaking/notching characteristic, centred on its selected frequency (whereas a shelving filter cuts or boosts all frequencies beyond the nominal setting). Peaking and shelving filters in the same range can actually be an extremely useful combination — perhaps the one way in which this EQ could be operationally improved, at modest cost, would be a switched option to shelve the HF at a lower frequency, say 6 or 8kHz, but at this price, I am not going to complain.

The two sweep stages utilise dual-concentric controls, offering a similar +/-14dB, from 300Hz to 12kHz for the mid, and 20Hz to 600Hz for the LF stage. Personally, I would rather see a few more frequency markings around the EQ controls, not because I 'EQ by numbers' rather than by ear, but because I think for many users it can be educational — if you find an EQ setting that works particularly well on an instrument, it is worth spending some time thinking about the response you have imposed on it, and its relationship to the sound you are hearing. It doesn't mean that it is necessarily going to work equally well in another situation, but you can learn some useful general principles. Better frequency control calibration would take some of the guesswork out of determining a probable value for a control setting.

Like all the present Allen & Heath range, the GS3's EQ is pleasantly responsive, and reliably predictable in its effect. The fixed 'Q' (bandwidth) of the sweep stages allows both creative and corrective work, being selective enough for cutting particular frequency bands without sounding too narrow and harsh in boost applications. Used within the constraints of common sense, it is a most capable EQ, and I can't see any GS3 owner being disappointed with it. An EQ in/out switch is provided, but EQ-gain controls are also centre-detented, helping you avoid accidentally affecting bands that you want to leave 'flat', when you only want to apply EQ in one area.

A Peak overload LED monitors the channel level, post-EQ stage, flashing to indicate an approach within 3dB of clipping. The channel Insert points are pre-EQ, which is the best compromise when not switchable pre/post — the performance of level-dependent devices is not therefore affected by any alterations you make to the EQ. With inserts also provided on the groups, you can, in effect, have it both ways, using a gate on the channel insert, where the threshold setting will only be affected by a subsequent channel Gain adjustment, and a compressor on the group insert, where it will obviously receive the post-EQ signal, often preferable for compression.


The GS3 incorporates four dedicated FX auxiliaries in a versatile configuration. All are post-fade, fed from two pairs of dual-concentric controls. Auxs 1 and 2 are fixed in the channel path, whilst 3 and 4 are 'floating' between channel and monitor and can be switched into either circuit. Aux 4 has a straightforward Chan/Monitor selector, whilst the operation of Aux 3 is a little more subtle. When an aux 3 send is switched into the monitor path, it actually feeds the auxiliary 1 bus, thus giving you an aux bus common to both signal paths. This can be used for your primary effect, probably your main reverb, which any source, from either signal path, might need to access. On desks without a common aux, it has usually been necessary to rely on the fact that most 'stereo' FX devices simply parallel their inputs prior to processing, so you could connect two different auxs to the same device. The disadvantage of that system is its lack of flexibility, whereas the GS3 configuration effectively lets you determine 'paralleling' on an individual basis; a send can still be aux 3, in the channel path, if it is not needed for aux 1 duties on the monitors.

All four auxiliaries are available for FX at all stages of the recording process, for there is also a dedicated pre-fade stereo Cue mix bus to feed a headphone foldback monitoring system; the individual channel sends are obviously mono, but stereo effect return signals can be incorporated, and other, genuinely stereo sources selected, such as the stereo bus, or playback from a 2-track machine. Selection of the stereo bus as the cue source does not disable the individual cue sends, so you can use the control room mix as the basis of a quick foldback balance, and then subsequently lift some signals from the channels/monitors, as necessary.

Monitor channels have their own Cue sends, in fact feeding an entirely separate bus from the channel Cue (the two are combined at the Stereo Cue output). In practice, you would be unlikely to want separate foldback sends from the two signal paths, but you can press the cues into service as extra FX sends, provided you are prepared to work with their being pre-fade — pre/post switching for the cues would have been a significant operational enhancement. Accessing the signal pre-fader/monitor level, the Cue send does not therefore follow the mute status (the mutes are always post-level control). The FX sends however, are muted along with the channel or monitor they are sending from.

The FET-switched, electronic Mute element accessed by the MIDI Mute Processor is included on all input channels, monitor channels, aux bus send masters, and dedicated FX return inputs. Mute operation is effectively silent, and has a 'soft' action which can interrupt a continuous signal without generating the audible click of a 'chopped' waveform. Mute status is confirmed by an adjacent LED (lit for signal muted). As they have to be remote-operated, the switches themselves are obviously non-latching (momentary), and not therefore physically self-indicating.

A standard Pre-Fade Listen (PFL) circuit is provided for isolating a signal into the monitoring only, without interrupting any of the main signal paths — PFL is described as 'non-destructive', as it can be used freely during recording or mixing. The channels are completed by the Pan control and a 100mm Alps fader, with the top half of the fader travel running alongside the small routing matrix. The matrix allows the channel to access the mix bus and pairs of the eight sub-groups. Odd/even-numbered tracks are selected individually via the Pan control, as usual. There are eight group faders located to the right of the inputs, but the actual group outputs are located above the channel strips. Groups are paralleled across the desk in blocks of eight; thus group 1 feeds the group output on both channel 1 and 9 (and in an expanded console, 17, and 25).

Every channel is also equipped with a Group/Direct switch. This overrides the group assignment, sending instead from that output the post-fader, post-EQ signal from the channel — a simple to use, yet flexible configuration. Provided you utilise a full loom (with an individual connection to every track, not just eight tape-sends paralleled at the tape machine) the GS3 therefore has the ability to access as many tape tracks as it has channels, without any patching being necessary. But perhaps more importantly for some users, it can also address this number of tracks simultaneously, if necessary.


The rotary Monitor Level and Pan controls are a dual-concentric pair, with Monitor EQ consisting of two fixed-frequency shelving filters (+/-14dB at 100Hz and 10kHz), with centre-detented pots. There can be no doubt that a separate EQ, rather than a partially transferable one, is preferred by most operators of small multitrack set-ups, particularly those with less experience of the complexities of assignable facilities.

Whether you view the EQ facilities as limited or adequate possibly depends on your method of operation; if you are using monitors as inputs to the mix because you have a pile of synced MIDI sources, why not send these through the more sophisticated channel EQ, assigning the tape signals to the monitors? The tape signals may have been EQd once already, during recording; if you have things on tape sounding much as you want them in the mix, the chances are that a gentle 100Hz, or 10kHz tweak may be all that is required. Monitors have the same PFL and Mute facilities as the channels, and are completed by the send to the Monitor Cue bus.

The eight sub-groups have group-to-output switching for audio sub-grouping during mixing. With no pan facility, odd-numbered groups always feed the left bus, and even-numbers the right, but the chances are that your sub-groups will be stereo anyway. Metering, for the groups and the monitor source (normally the stereo bus), is via 10 10-segment LED ladders, with a peak-reading, fast-attack/slow-release characteristic matching that of most semi-pro multitracks. It is also sensibly scaled to maximise resolution in the most important area, with a 1dB step on either side of 0VU. The ganged stereo mix bus master used for the S2 has been ditched in favour of separate faders — a configuration I personally prefer.

"The GS3 from Allen & Heath really does have everything we have come to expect of most of the market-leading products in this price bracket — and then some."


The GS3 is well-endowed with FX returns, incorporating four stereo channels. Each return has a Gain control, for overall sensitivity adjustment, plus Level and Pan, and two-band (100Hz and 10kHz) EQ. A full track-routing matrix is featured on all returns, for sending FX to tape or returning into an audio sub-group. There is also the essential send to the Channel Cue bus for incorporating effects in the headphone foldback mix. The FX returns are sufficiently well equipped to be considered simply as additional stereo line-level channels, if necessary, for they have PFL and Mute facilities, and are lacking only auxiliary sends (aux sends from FX returns used to be the primary means of regenerating echoes, but the facility is now always included within the effect itself).


The feature-laden GS3 has practically everything you might want in the way of master facilities on this type of desk. Control room monitoring, governed by a nice prominent level control, includes both Mono and Loudspeaker Mute facilities, plus switching for an alternate monitor system, and two external two-track sources — with both 'externals' deselected, the source is always the mix buss or PFL signal. An integral talkback mic is incorporated, switchable individually to cues, for talking to performers, or to the groups for 'take' identification on tape. There is also a dual-frequency 1 kHz/10kHz oscillator provided for test and alignment purposes (but why not the traditional basic set, with 100Hz as well?). The single headphone output is located right out of the way below the 'armrest'.

The innovation of the integral tape-dubbing facility first seen in the S2 has naturally been retained. This allows each 2-track's input to be switched between the mix bus or the output of the other 2-track — a very welcome inclusion indeed, particularly in a non-patchbay set-up.


The GS3 offers a further enhanced version of Allen & Heath's comprehensive MIDI Mute Processor (now up to V4 Plus). MIDI muting is an extremely useful facility, providing a means of non-destructive editing, cleaning-up stray sounds on tape, and minimising noise. It is also a big help with one of my favourite recording techniques, track-splitting, which involves feeding a single track into two channels with different settings, switching between them to achieve automated level, EQ, or FX changes. 33 static 'snapshots' (Patches) of the mute setup across the entire console can be internally memorised for instant recall, either manually, or via MIDI program changes. Mute data is also output over MIDI, and can be recorded in an external sequencer.

The big new feature of V4, however, was the addition of an internal real-time recording facility, referenced to MIDI clocks and Song Position Pointers from an external source, such as a sequencer (synced to tape, unless you have an exclusively MIDI system). With the real-time mute data recorded internally, the system is able to adopt the correct configuration of mutes regardless of where the clock sequence is started, without having to rely on an external sequencer having a 'chase' facility — in practice, V4 Plus configures virtually instantaneously on receipt of clocks.


You can use Patches in combination with individual mutes as part of the real-time 'song' data — Patch zero is reserved, however, for an initial set-up for the desk on power-up, and for starting 'automated' songs from a consistent configuration. Patches used within a song are automatically incorporated within its data. When a Patch is recalled or updated, the system is defaulted to automatically increment the Patch number for you, allowing you to manually recall sequential patches very rapidly. However, this mode of operation (Auto Update) can cause a little confusion initially — as soon as you recall Patch 1, the display increments to 2 (on the assumption that this may well be the next one you require). I have even known some people think their system is faulty because "it doesn't recall the same mute set-ups I store". They have failed to grasp — perhaps understandably — that if the display reads Patch 2, it is Patch 1's mutes that are presently active. Pressing the Toggle switch allows you to view the presently active Patch, at any time, but you would be unlikely to work that one out spontaneously.

The MMP is almost a victim of its own ease of use here; most people think they can busk a system like this from the outset, and don't bother to read that bit of the manual. Auto Increment is a useful feature but, with hindsight, I am now inclined to think that Allen & Heath might be well advised to consider defaulting it to Off, allowing the user to adopt it once he has a clear understanding of the system, rather than having to deal with it at the outset.


Both real-time and off-line editing is possible. Because basic note and controller messages are used, you can export mute data by 'playing' it into an external sequencer, and then employ its visual interface and familiar editing procedures. Once altered, you can re-load data by 'playing' it back into the MIDI In of the GS3. The MMP has sufficient resolution for these operations to be performed at high speed, so you can use the sequencer's maximum tempo setting, drastically cutting down the transfer time. It is not necessary to run tape at all for these procedures. External editing is as powerful as the sequencer used will allow; it not only offers greater precision than real-time entry, but also makes possible useful operations like copying data from one channel to another (make a duplicate of one channel's data and then transform its notes to a different pitch, retaining the velocity values — the new data will then affect a different channel).

The on-board memory capacity will allow almost 2,000 individual mute and patch recall events to be stored. Data from the volatile working memory, referred to as the Working Song, can be transferred into one of 32 battery-backed RAM Song Memories, clearing the working memory for new data. Complete Songs or individual Patches can be archived to an external sequencer, or MIDI data recorder, via SysEx. Alternatively, the individual mute note or controller data could be stored as part of the sequencer's song file. Channels can be isolated from the MMP at any time, perhaps to allow an input for which mute data has been written to be temporarily used as a source channel for a further overdub. If all channels except one are isolated, the remaining channel alone can be transferred-out for editing. This is easier than separating the data on arrival, if you only want to look at one channel.


Allen & Heath's MIDI Mute Processor is not only a very effective performer, it has also gained a reputation for being particularly easy to use, with just two banks of four switches to consider, plus a 2-digit LED display. The system can operate on any channel (default = 16), with MIDI note on messages normally used to identify channel numbers and mute status (note number = mixer channel, velocity value high/low = Mute On/Off). There is however, an option to employ controller messages instead, which might perhaps be necessary in a system where you cannot afford to devote an entire MIDI channel to mute data; the chosen controller assignments avoid those commonly used by MIDI voice modules, and could thus co-exist on the same channel as note and conventional controller data.

The addition of the MIDI Function Keys, which are actually entirely independent of the MMP (although they can send a program number to the MMP for Patch recall), will further enhance the MIDI integration of the console, without adding significantly to system complexity. There are seven Function keys (with 'F7' paralleled to a footswitch), plus a Learn key. The Learn mode can be used to program each key with a separate MIDI message (note on/off, controller messages, short SysEx block, or whatever else you care to throw at the desk's MIDI in) for both key press and key release.

Like the Patch memories, all Function commands are memorised when the console is powered-down. Sensibly, the GS3 is shipped with a set of defaults for interfacing with a suitably MIDI-equipped tape transport, such as a Fostex G-series or R8 via the MTC1, or any Tascam with an Accessory 2 socket via the new MMC1 interface, offering MIDI record, play, stop, fast-forward, and rewind controls. The footswitch corresponds to the F7 key, which controls the record function in the default set-up.


Function keys can also be employed for instant recall of specific Patches, without having to go via the data entry keys/Recall. If you have no use for a MIDI remote control panel on your mixer, you could use all seven keys for instant Patch recall, but the default set-up uses just two — Patch 32 and Patch 31 — for a specific purpose. If Patch 32 (F2) is stored with all mutes on, it can be used to create a stereo solo-in-place facility, by subsequently unmuting the channel you want to hear. Quickly updating Patch 31 (F1) with the present set-up of the desk, before you recall 32, allows you to easily return to the original status again. A solo in place therefore requires three key-presses (four if you are not presently selected to Patch 31): Update, to register the present set-up into 31 (F1); then F2 to mute everything; followed by the individual mute (un-mute) of the channel you wish to hear. For basic solo-in-place, it probably seems hardly worth the bother; however, the facility can be extended to 'solo-in-place-with-effects', and that is certainly worth having. If Patch 32 (F2) is memorised with the effects return channels left unmuted, these will be preserved during a Patch Solo operation. Other channels' effects returns will not be heard at the same time, as their sends will be muted along with their main signal path (aux sends are post-mute). The MIDI Function Keys are an excellent extension to the powerful facilities of the MIDI Mute Processor.


Allen & Heath's new GS3 is a most comprehensive desk, ideally specified for the typical working practices of semi-pro multitrack/MIDI combined operations. Subjective audio performance is impressive at this level of the market, clean-sounding, with low noise, and decent headroom and crosstalk levels, but it is primarily its remarkable line-up of operational features that will get the GS3 noticed. Above all, it manages to make many operations that little bit easier for the user, with a minimum of shared facilities, and plenty of options. Despite the number of features crammed into the compact dimensions, the GS3's control surface, although dense, is never confusing. Everything follows logical, and virtually standard, procedures, but for the inexperienced operator the unusually good GS3 owner's manual may prove particularly instructional.

The extension to the MIDI facilities is another exciting aspect of this design — we will undoubtedly see increasing implementation of the newly agreed MIDI Machine Control standard in the near future. The GS3's MIDI Function Keys may be primarily intended for use as a universal MIDI remote, but as they are programmable, users may, of course, find other applications relevant to their own set-ups.

The GS3 from Allen & Heath really does have everything we have come to expect of most of the market-leading products in this price bracket — and then some. It is also cleverly pitched, sitting equally comfortably in either a low-end one-inch 24-track set-up, for which it would not be under-specified, or a de-luxe quarter-inch 8-track-plus-MIDI package, for which it would not be over-priced. If you are buying in this highly competitive sector of the market, it would be impossible not to include the GS3 near the top of your evaluation list.

Further information

GS3 16:8:16 £2,231 inc VAT.
GS3 24:8:24 £3,172 inc VAT.
8-Channel expander module £1,091

Harman Audio, (Contact Details).


Frequency Response: 20Hz to 20kHz (+0/-1 dB)
Distortion: <0.008%THD (1kHz)
<0.02%THD (10kHz)
Noise (rms, 22Hz to 22kHz):
Mic equivalent i/p noise: -127dBu (ref. 150 Ohms source)
L-R mix noise: -80dB (ref. 0VU)
Group mix noise: -80dB (ref. 0VU)
Crosstalk: Better than -80dB (61 kHz)
Mute attenuation: -90dB (1kHz)
-70dB (10kHz)
Mic Gain: +10dB to +70dB
Line Gain -10dB to +20dB

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Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - May 1992

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Mixer > Allen & Heath > GS3

Review by Dave Lockwood

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> Korg 03R/W Synth Module

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