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Multi Effects Processor

Article from Sound On Sound, October 1989

David Mellor samples the delights of a multiple effects unit that can create up to nine high quality effects at the same time.

I wonder what 'SGE' stands for? It doesn't say on the unit, nor in the manual, but there must be some reasoning behind this mysterious monogram. I have a feeling that the original purpose of this unit was meant to be for Stereo Guitar Effects, but then some bright spark stood up and commented that 'if we call it a guitar effects unit, keyboard players won't buy it'. Well he could be right about the tendency for keyboard players and guitar players to be not exactly on the friendliest of terms as they compete to be the leader of the band and play the flashiest solos on stage.

Sound On Sound, as you know, is not a guitar orientated magazine, so if the SGE was just going to turn out to be a glorified fuzz box then its reader appeal would be limited, although a well designed unit like the ADA MP1 guitar preamp, with real valves [SOS Nov 1988], certainly has valuable potential for adding 'bite' to synthesized and sampled music. But as we shall see, even though the ART SGE has one of the best distortion effects around, it's use is not limited to turning the plain sound of the plucked string into screaming heavy metal overdrive. The combination and quality of the effects created by the SGE will command eye-level accommodation in any studio's rack.

Multiple effects units have had a glorious history since their initial introduction in the form of the Yamaha SPX90. The original SPX (now brought up to date in the form of the SPX900 and SPX1000) was a great piece of gear, but it had two drawbacks. The first was the sound quality, which was good but not great, if you know what I mean. Effects such as compression, gating or equalisation, which you would use on their own rather than mixed with the input signal, showed up the lack of high frequency response. The second drawback was that the SPX didn't replace a rackful of single effects units because it could only produce one effect at a time.

I'm not criticising the SPX for these problems because it was excellent in its day, but times have changed. One by one, manufacturers have developed units which overcome these two criticisms. Now we have the ART SGE, offering a 20kHz bandwidth and up to nine effects at the same time. With minor restrictions, which I shall explain shortly, the SGE can indeed fulfill the function of an entire effects rack.


'How do they squeeze it all in?', is the first question that comes to mind when you are presented with a unit that can create 16 different effects (the effect count depending on what you define as a 'different' effect), nine simultaneously. The second is 'How do you control them all?'

Well, I'm afraid I don't know the answer to the first question, but after several weeks of experimentation I have come to the conclusion that the SGE offers simple and accessible control over all of its many parameters. Obviously, the more parameters there are, the more the scope for confusion. But even though there is a certain amount of button-pushing involved, you soon get the hang of making the box sound the way you want it to sound. Many of the parameters, although they are scaled from 0 to 100, have only a limited number of steps along the way. This seems to me to be a good compromise between control resolution and ease of use.

Before I come on to effect selection and parameter editing in depth, let's look at the basic internal structure of the SGE. The inputs and outputs are stereo, although the processed signal is mono, or with an artificially generated stereo effect as in the Reverb and Pan processes.

The first stage of processing is analogue. Shock horror! Yes, even in the digital age, some things are best left to old-fashioned processing techniques. The SGE's range of analogue processors includes Compressor, Equaliser, Distortion, Harmonic Exciter and Expander/Gate/Envelope Filter.

The digital effects include a Low-Pass Filter and various Reverbs and Delays. In this stage, the effects generate stereo information where appropriate. The balance between the analogue and digital effects is set by a sliding Mix front panel control. Alternatively, if only digital effects are required, the analogue stage can be completely bypassed and the Mix control sets the balance between the true stereo input and the stereo processed signal.

Not all combinations of effects are allowed on the SGE. For example, you can't compress the reverb. As luck would have it, compressed reverb is one of my favourite effects, but I can always patch in my separate compressor. Also, in the digital effects section there is only a certain amount of computing power. This means that if an effect takes a lot of brainwork to create, then other effects cannot be used at the same time. For example, pitch changing is hard work for the SGE (as you would expect it to be) so the Flange, Chorus, Pan, Reverb and Delay effects are all locked out. This might seem like a drawback, but it is only logical for it to be possible to use all the available processing power where necessary, and pitch changing is not a simple process.

Fortunately, although some combinations of digital processes are not possible, all of the analogue effects are available at any time.


For me, the main attraction of the SGE's analogue effect processor is the Distortion feature. If you listen to the records in the charts at the moment (I know it's painful sometimes, but give it a try), you will hear a guitar on nearly every one, along with the by-now 'traditional' synths and samplers. There is nothing like a well-played guitar to add life to a track, and I am certainly concentrating on adding a bit of guitar to my own music as much as I can.

One thing that an electric guitar needs to make it sound good is distortion. Clean, undistorted, guitar does absolutely nothing for me, nor my music. But getting good distortion rather than 'fuzz' is not so easy. If you have a soundproof studio, then you can crank up a Fender Twin or Marshall stack to get the right sort of sound. If, like me, you don't have such facilities on hand, then you make do with a 'Heavy Metal' pedal or something similar (actually, a valve practice amp can make some highly acceptable sounds without too much volume).

At the recent British Music Fair, I made guitar processors the theme of my visit, and listened to just about every one, along with a guitarist friend. The principal conclusion I came to is that, for many manufacturers, musical distortion is as yet an unattainable goal. I didn't get to try out the SGE until it arrived for review, but I had heard that it just might be a machine worthy of a close look.

To do the unit justice, I had my guitar serviced at my local dealer, Hank's, and put on a new set of my usual 24-carat gold-plated strings (really!) and embarked on a journey through the presets...

I have to say that I was amazed at the quality of the Distortion presets, considering that there are no valves in the unit (I did try to check but the review unit seemed to be glued together). The variety of sounds, from mild overdrive to harsh grit, is amazing, and definitely rivals the valve-driven ADA MP1 guitar preamp I reviewed back in the November 1988 issue.

Having such good distortion in a handy box gives you a good feeling, and the other analogue effects can call up a wide range of sounds very easily. Even if compression, gating etc is available in separate units, when the effects are so easy to set up as they are here, you have more incentive to try for a new and original sound.

There is a choice in the routing of the analogue effects. Not 100% flexibility, but along the right lines. Compressor, Distortion and Expander/Gate always come in that order, but the Harmonic Exciter may be placed at the very beginning of the chain or between Distortion and Expander/Gate, so you can excite the Distortion if you want to.

The EQ can go either before the Compressor, or after the Distortion. Either of these options can be very useful, but having EQ available after the Distortion is essential for when you need to tame the effect to a warm 'valve' glow. But having said that, the EQ doesn't fulfill every equalisation requirement. There are only three bands - 100Hz, 1000Hz and 10kHz - with 12dB of cut or boost. I did find myself patching in extra EQ to get the sounds I wanted.


After the analogue effects, or operating directly from the input signal if you wish, comes the digital processing section, with Chorus, Delay, Reverb, Pitch Changing, and their variants.

To name names, the digitally generated effects are: Low Pass Filter, Flanger, Chorus, Pitch Transposer, Panner, Mono Digital Delay Short, Mono Digital Delay Long, Reverb 1, 2 and 3, Gated Reverb 1,2 and 3, Tapped Delay Short and Long, Regenerative Delay Short and Long, Stereo Delay Short and Long. Not a bad collection, I would say. Details on these effects and their parameters are supplied in a separate panel, but what about the important effects such as Pitch Transposer and Reverb? What do they sound like?

To start with the pitch changing function, it should go without saying that you are not going to get the same quality of effect in a multieffects unit at this price as you are in a more expensive unit whose main function is pitch changing, such as those in the famous Eventide range. But having said that, the effect obtained here is very suitable for use as a 'thickener' to the main sound. There are three types of pitch changing algorithm provided, each of which will suit a different kind of input. 'Smooth' takes a little time to process the input and provides, as it might suggest, a smoothly pitch changed output with little glitching. 'Quick' provides instant processing with almost no delay, but causes some glitching and cannot successfully process chords at high transposition ratios. 'Normal', obviously, falls in between.

To create 'Marvin the Paranoid Android' type pitch change effects (referring to an effect used in 'The Hitch-Hiker's Guide To The Galaxy'), it is possible to couple in a delay line which feeds the output of the pitch changer back to the input so that a sequence of pitch changed echoes is produced. MIDI-controlled pitch changing is also possible, the degree of shift set according to the value of a MIDI Note-On message.

Although pitch changing is a technically difficult exercise, it is not an effect for everyday use. Not like reverberation. Reverb, of one kind or another, is used on virtually every recording made. Even if it is not generated by an effects unit, it is still there in the form of natural reverb or studio ambience. And because we are used to hearing reverberation in our everyday lives, the ear demands high quality reverb from any effects unit. But the level of quality which we desire is not available from every black box on the market.

Since the SGE is a multiple effects unit, there might be the suspicion that the quality of the Reverb programs may not be all that special. Well, although in absolute terms I couldn't match it against a Lexicon or AMS, it is very good indeed. In fact, if it didn't have all the other effects I would be tempted just by the sound of the reverb. It has character.

There are various Reverb alternatives on offer. Both Reverb and Gated Reverb come in three strengths. Strength 3 is suitable for use as an effect in its own right. Strengths 1 and 2 are simpler algorithms which are better suited for use in conjunction with other effects. (Depending on the combination of effects selected, there may not be enough processing power to support Reverb 3).

Reverb parameters are: Type; Hall, Room, Plate or Vocal. Decay; 0 to 25 seconds. HF Damp; 0 to 50% (simulating the effect of reflecting surfaces that are less reflective at high frequencies). Position; Front to Rear, in percentage increments (simulating the listening position in the room). Diffusion; 40 to 100%. Level; 0 to 100% (setting the direct/reverberant sound balance).


For a compact unit with just a small number of buttons, the selection and editing of effects programs is just about as simple as it could be. Assuming you start with a blank program, pressing the Edit button transports you to the world of multiple effects.

To add any of the available effects it is necessary to press the Add Effect button as many times as is necessary to locate the effect you want. Then you press Recall/Enter to select it. This process is repeated until you have entered all the different effects you need (or until you exceed the maximum number, which may be up to nine according to which particular effects you choose). This is a simple procedure, but it does entail a lot of button pushing. Still, we are getting used to it these days, aren't we? Effects are deleted in a similar way.

To edit the effect parameters there are two Select buttons which step forwards or backwards through all the parameters in all the active effects. Adjustments are made with the Value buttons. This means even more button-pushing, but you do get there in the end. When you have something you like, it can be stored in any one of 200 preset memories - a generous supply. To get you started, the unit does come with 99 excellent presets stored in the first 99 memory locations. You can 'unlock' the presets and overwrite them with new programs if you wish, but they can always be restored when necessary.

The architecture of the SGE, with its separate analogue and digital effects stages, means - so I discovered - that you need to treat this multiple effects unit rather differently to ordinary effects units when you hook it up to a mixer. Let me give you an example: Suppose you want to use Distortion and Reverb effects on a guitar - a very simple combination. In the case of Distortion, you almost certainly want to use the effect signal by itself, not mixed with the clean input signal. But Reverb is almost always used as an enhancement to the original sound. If you had two separate units, the way this would normally be done might be to patch the distortion unit into the channel insert point of the mixing console, and use an auxiliary send and auxiliary returns to mix in the right proportion of reverb. Since the SGE can't be split in this way, balancing the Reverb added to any of the analogue effects needs to be done using the Mix control.

The way I would patch the SGE into my mixer would be to use the channel insert send to supply the input signal to the SGE, and return the SGE's output to two extra channels. These channels would be sent to tape, but not the original guitar input channel. To me, this is a new way of going about adding effects, but I am certainly willing to modify my usual techniques to achieve the SGE's full potential.


'Jack of all trades, master of none' is certainly not a label that can be attached to the ART SGE multiple effects unit. In fact, the SGE is an outstanding distortion processor, and a digital reverb with true character. The other effects are similarly up to standard. Despite a certain amount of button pushing, the SGE is easy to understand and use. Be warned that to try it out, even briefly, is to expose yourself to severe temptation.


£629 inc VAT.

Harman UK Ltd, (Contact Details).


The ART SGE has a valuable, and powerful, feature called 'Performance MIDI'. This allows the SGE to have up to eight of its effects parameters adjusted in real time via MIDI. The MIDI input to the SGE can be Note Number, Note-On/Off Velocity, Channel Pressure, Polyphonic Aftertouch or any MIDI Controller. For instance, the manual gives an example where the Mod Wheel adjusts the high frequency EQ, the Pitch Wheel alters delay time, Note-On Velocity controls the flanger's regeneration, and Note Number controls the position of the reverb. The degree of control is very flexible and offers great scope for experimentation.

As well as Performance MIDI, the usual MIDI features are available: MIDI Program Change messages may be used to select any desired Preset. It is possible to set up a MIDI Program Table to determine which Program number selects which Preset. Preset parameters and the MIDI Program Table may be transmitted as System Exclusive information, and could therefore be recorded by a sequencer along with the music.

Although the ART SGE has no MIDI Thru connection, a MIDI Merge function is available where incoming MIDI is combined with any MIDI data generated by the unit and transmitted via the MIDI Out. The claimed transmission delay is under one millisecond.


The ART SGE has one particularly bad point which needs correcting by the manufacturer. When mains power to the unit is switched off (there is no mains switch on the unit itself), it emits a very loud and high pitched noise. Although other audio equipment, of all types, often makes a noise during switch-on or switch-off, I have only heard one unit (not now in production) worse than this.

It is always good practice to turn the amplifier on last and off first in any system, to avoid any switching clicks created by the other equipment passing through to the speakers and possibly causing damage. It is essential that the switch-off noise produced by the SGE unit does not get to the speakers or there may be a definite risk of damage to the high frequency drive units.


Harmonic Exciter Position (pre-Compressor or post-Distortion)
Range (0 to 100%, increases perceived effect)
Equaliser Position (pre-Compressor or post-Distortion)
100Hz (+/-12dB)
1kHz (+/-12dB)
10kHz (+/—12dB)
Compressor Slope (Off, 2:1,4:1, Limit)
Drive (12% to 100%, increases compression effect)
Release (Slow or Quick)
Output (12% to 100%)
Distortion Type (Overdrive 1, 2 and 3, Distortion 1, 2 and 3, Turbo Overdrive 1, 2 and 3, Turbo Distortion 1, 2 and 3)
Drive (12% to 100%, increases amount of distortion)
Bite (On or Off)
Output (12% to 100%)
Expander/Gate Type (Expander, Noise Gate, Expander+Gate, Envelope Filter)
Source (Input, post-Compressor, Output)
Range (12% to 100%)
Tuning (12% to 100%, affects frequency range of Envelope Filter)
Output (12% to 100%)
Low-Pass Filter HF Cut (665Hz to 15kHz)
Flanger Type (Pre or Post - 'Post' places Flanger last in chain, 'Pre' places Flanger in parallel with Reverb or Delay effects)
Width (0% to 100%)
Speed (0 to 15)
Regeneration (0% to 100%)
Chorus Type (Pre or Post)
Width (0% to 100%)
Speed (0 to 15)
Delay (0 to 66 milliseconds)
Pitch Transposer Type (Smooth, Normal, Quick)
Pitch (+/-12 semitones)
Fine (+/-1.00)
Base Key (MIDI Note Number 1-127)
Regeneration (0% to 100%)
Level (0% to 100%)
Panner Modulation (0% to 100%)
Speed (0 to 15)
Mono DDL S(hort) Delay (0 to 100 milliseconds)
Mono DDL L(ong) Delay (0 to 240 milliseconds)
Reverb 1 Type (Hall, Room, Plate, Vocal)
Decay (0 to 25 seconds)
HF Damping (0% to 50%)
Position (Front to Rear in % increments)
Level (0% to 100%)
Reverb 2 Similar to Reverb 1
Reverb 3 Similar to Reverb 1 plus;
Diffusion (40% to 100%)
Gated Reverb 1 Type (Slope, Flat, Reverse A, Reverse B - determining the envelope of the gating effect)
Decay (0.05 to 0.25 seconds)
Diffusion (60% to 100%)
Level (0% to 100%)
Gated Reverbs 2&3 Similar to Gated Reverb 1
Tapped Delay S(hort) Type (Selection of 18 tapped delay line algorithms with varying pattern and envelope)
Taps (1 to 7)
Delay (0 to 100 milliseconds)
Level (0% to 100%)
Tapped Delay L(ong) Similar to Tapped Delay S but with longer delays
Regen DDL S(hort) Delay (0 to 100 milliseconds)
Regeneration (0% to 100%)
Level (0% to 100%)
Regen DDL L(ong) Similar to Regen DDL S but with longer delays.
Stereo DDL S(hort) Delay L (0 to 360 milliseconds, left channel)
Delay R (0 to 360 milliseconds, right channel)
Regen (0% to 100%)
HF Damp (0% to 100%)
Level (0% to 100%)
Stereo DDL L(ong) Similar to Stereo DDL S but with delays up to 500 milliseconds.

Also featuring gear in this article

Previous Article in this issue

Musicsoft Syncman & MIDIman

Next article in this issue

Hollis Research MIDIman

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

The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...


Sound On Sound - Oct 1989

Donated by: Mike Gorman, Bird201

Scanned by: Mike Gorman

Gear in this article:

Studio/Rack FX > ART > SGE

Gear Tags:

Digital FX

Review by David Mellor

Previous article in this issue:

> Musicsoft Syncman & MIDIman

Next article in this issue:

> Hollis Research MIDIman

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