In an ideal world you'd have an extra MIDI sound module delivered with your daily pinta. However, most of us have to grab the cream when we can afford it. So, if the milkman can't help in the quest for a library of consistently useable sounds, we will. Take three of the latest quality units available - Yamaha's TG300, E-mu's Proteus FX and Korg's X3R - whisk thoroughly in the mix laboratory of sonic response, et viola - everything you need to know to make the right purchase.

The concept of the MIDI module or expander is now so well-established that it scarcely seems worthy of a formal introduction. The advantages of adding a module are obvious: you get a whole load of new sounds without having to dispose of your well-loved keyboard, and you don't get charged for the bits of another keyboard you don't need. 'Module' means building-block, anyway, implying an additive approach which is well suited to synthesis.

However, with the advent of General MIDI, the other overtone of the word 'module' - standardisation - has begun to dominate the world of synthesis and detract from the former benefits associated with buying a box of new noises. It is generally unnecessary to have more than one module which is GM-compatible, if you only intend to play MIDI song files. If, however, you're interested in programming and experimenting with sound, modules which offer the full capabilities of their keyboard counterparts can be highly satisfying additions to your studio's sonic capabilities.

The three modules we're looking at here are typical in combining synthesis and GM compatibility. Each of them therefore provides a good deal of flexibility, and would get the first-time buyer off to a more than useful start. The Yamaha TG300 and the E-mu Proteus FX are priced at just over £600, whilst the Korg X3R weighs in at £1199 RRP - but you do get an onboard sequencer for the extra bunce. The following is our appraisal of each unit; we'll leave the final decision up to you...

Yamaha TG300

Having tackled the lower end of the General MIDI module market with the TG100, Yamaha set their sights on the upper end with the 300. The TG300 has more airs and graces than its cheaper cousin, with a cleaner sound, a larger selection of patches, more programming options, and a much-improved user interface complete with a sizeable backlit LCD.

The requirements of General MIDI are certainly satisfied: a bank of 128 instrumental sounds, a 'drum kit' of 47 drum and percussion sounds, 16-part multi-timbrality and at least 24-voice polyphony. However, it also goes beyond these requirements - as does, it must be said, just about every other GM instrument (including the Proteus FX and the X3R).

On the quiet, many manufacturers have adopted the multiple drum kits of Roland's GS Format. Yamaha did this on the TG300 (as, indeed, they did on the 100), so in addition to the Standard Kit you'll find, for instance, Power, Electronic and Brush Kits, all conforming to the GS sound selections and note assignments.

Features

Yamaha have also implemented additional instrumental sounds by adopting the sound-bank concept of GS Format. More unusually, the company have given the TG300 two sets of the same 128 GM instrumental sounds, GM-A and GM-B, each with its own GS-style bank settings. Alternatively, you can select C/M or Single performance mode; the former putting the instrument into 16-part mode, while the latter lets you play only one sound at a time - but you can choose from 128 programmable sounds, each of which can be assigned any one of 32 preset or 16 programmable effects programs. This contrasts with the three multi-timbral modes, where one effects program is common to all 16 parts.

Single mode's programmable patches are also available in GM-B mode (minus specific effects) for use in a multi-timbral setting. This is a good thing, because there are some very useable preprogrammed patches among them - and in addition any sounds which you've programmed yourself can be used in a multi-timbral setting.

On the subject of programming, the TG300 gives you full access to the sound parameters, including filtering (with resonance control), LFO and all the envelopes - so you can really dig in if you want to. You can also edit the 'drum kits', changing sound assignment, coarse and fine pitch, level, pan, reverb send and chorus send settings for each note in the kit. However, drum-kit editing is done per multi-timbral part; edits are stored during power-down, but assign a new kit to a part and you'll lose them.

Effects processing on the TG300 is of a decent quality, and quite versatile. The module can provide up to three digital effects simultaneously, namely Reverb, Chorus and Variation. Not only this, but the Reverb and Variation effects are two-part, so for instance you can route a sound through distortion and then compressor or flanger, and then exciter.

Yamaha have often been criticised for producing convoluted user interfaces, but they do seem to have been improving in this area recently. The TG300 is a case in point; as well as adopting a more graphic approach, with an on-screen 'mixing desk', they've come up with a refreshingly straightforward user interface for the 300 which makes the instrument a pleasure to use.

So what of the all-important sounds? Well, the sound quality is especially clean. Ensemble sounds, including pads and atmospheres, are very effective, with a pleasing warmth to them; the solo instrumental sounds are a much more mixed bunch, though - often on the thin side, many of them wouldn't win prizes for realism and accuracy either. However, the TG300 is supposed to be an ensemble instrument, for use in multi-part sequencing, rather than a solo player's instrument, and when you put a lot of these sounds together in an ensemble context they work very well. Other manufacturers are good at producing sounds which are excellent solo but just too full-sounding to work in an ensemble context.

Summary

A good general-purpose instrument (which is, after all, what GM is supposed to be about), the TG300 also expands on the basic capabilities set out by the General MIDI spec. The result is a GM instrument which doesn't feel too restricting. It's particularly easy to use, and the Part and Voice editing features are comprehensive. There's an overall blandness to the unit however, reflected mostly in the solo-oriented sounds, which lack body and have a tendency towards 'plinkiness'.

Proteus FX

Asked to name a sample-replay sound expander, most people would mention E-mu's Proteus, and that's indicative of the extent that this product line has defined the genre over the last few years. It's a simple concept, really. Pack as many high-quality instrument samples into a box as you can, throw in some digital effects, give it lots of voices and make it as easy to use as a can-opener. That's what E-mu did, and their ingenuity has been rewarded by massive sales that must have their rivals turning green with envy. It's not even as if the E-mu sample library is undisputedly the best - many people consider Kurzweil samples to be warmer and more musical - but they managed to put their samples into exactly the right package needed by sequencer users. They caught the other manufacturers off guard in 1989, and have never looked back since.

In addition to the three basic Proteus modules, covering rock/pop, orchestral and 'world' sounds. E-mu have also introduced Vintage Keys in response to the popularity of classic keyboards, and have branched out into the area of synthesis with their Morpheus module, which marks a bit of a departure for the company.

Since E-mu are obviously intent on creating as many 1U sound modules as possible, it could only have been a matter of time before they brought out a 'greatest hits' package, containing all the best bits from their Proteus range, and that's what they did with the the Proteus FX (which has samples from Proteus 1 and 2). And a jolly good idea it was, too, since buying a full complement of Proteus modules won't exactly break the bank. In fact, the FX is cheaper than its Proteus cousins, so no doubt there were some cost-cutting measures implemented to keep the price down - but not, most would agree, at the expense of the sounds.

Features

The FX is altogether cheaper-looking than the X3R and the TG300, though the layout of controls is very similar to the more expensive members of its own family. With headphone socket and volume pot on the left, LCD display in the middle, and power switch and function buttons on the right, the FX is an exercise in minimalism. Most of the work at the front panel involves using the cursor controls to select a parameter, and the data entry dial to change values. Moving to the back panel, you immediately notice where some of the savings have been made in production costs. No separate outs here - just a stereo pair, plus the usual MIDI connections. Power is supplied by an external unit.

Setting up sounds for use with sequencers is very simple with all the Proteus modules, and the FX is no exception. All you do is select the sound you want, assign it a MIDI channel, and adjust its volume level and pan position as required; then repeat the process for the other fifteen MIDI channels. Other pages can be called up to access the other functions, such as effects, transpose, master tune and so on. There are actually two effects processors, with the first handling reverb and delay effects, while the second has some more esoteric effects such as ring modulation and fuzz. Reverb is, not surprisingly, the most used effect, and there are a reasonable variety of algorithms available, including rooms, halls, chambers and plates. There's not much in the way of programmable parameters for the effects, just decay time for the reverb, but that keeps the operation quick and simple.

The FX contains 8Mb of 16-bit samples taken from the Emulator III library, and its 32-voice polyphony is adequate, though not exemplary (the stakes have been raised to 64-voice polyphony by some recent releases). The machine comes with 512 presets loaded into four banks, and half of these locations can be used to store edited sounds. Each of the four banks has its sounds organised in groups entitled keyboards, chromatic percussion, organs, guitars, bass, strings, ensemble, brass, reeds, pipes, synth leads, synth pads, synth sounds, ethnic, percussion, and special effects, and there are eight presets in each group. Changing banks is just a question of pressing the 'home/enter' button and turning the data-entry dial - and since the sounds are arranged the same in each bank, you can audition (for example) all the organ sounds with the minimum of button pushes.

The quality of E-mu samples is consistently good, from the grand piano in location 00 right through to the special effects that traditionally occupy the latter memory locations of sound modules. A good piano sound is essential for any sound expander these days, and luckily the Proteus has a variety of ivory-tinkling presets - the grand piano 00 is probably the most satisfying. Another essential, the Hammond B3, is well represented on the FX, too, with a variety of incarnations from the very well-behaved to the very raunchy - there's a few church organs, too, if you like that sort of thing. One area where the FX perhaps loses out is in the drum kits - not that they're dreadful or anything, but they are a bit staid and uninspiring. The sound effects section is a godsend to TV composers, providing instant atmospheres for every occasion: the guy who does the stings for BBC2 has definitely got a Proteus or four in his rack.

Summary

The overall impression of the FX is that it provides a large range of competent, if not outstanding, sounds and is perfect as a general purpose sound module. For anyone getting a MIDI system started, the FX is a particularly good first module to get, and provides a wide variety of sounds without you having to buy several of the standard Proteus modules. Whilst the FX is very good for constructing backing tracks, you may have to look elsewhere for top-quality lead or solo sounds, but a good sampler - rather than a GM module - would better provide these as you expand your system. Some of the samples are starting to sound a bit dated (particularly the drums), but if you do intend to get (or you already have) a sampler, this doesn't present an insurmountable problem.

Korg X3R

Korg commonly introduce modular versions of their workstation synthesisers within a few months of the keyboard's release. The sheer range and quality of voices offered by the X3 makes it the source of a rich vein of new keyboard textures and ideas. The question is: would the keyboardless version - the X3R - find a comfortable niche in your setup?

Korg are past masters at producing multi-purpose music boxes. Designing all-singing, all-dancing keyboard workstations has become almost second nature to them after they virtually invented the concept some six years ago with the M1 synthesiser.

The Korg X3, released in the latter part of last year, kept the workstation ball rolling and was hailed by many as the successor to the M1. The X3R, in turn, followed at the beginning of this year. Its internal electronics are almost the same, chip for chip, as those within the X3 - so you get the same sounds, the same synthesis process and the same software architecture.

It's 16-part multi-timbral (so you can play 16 different sounds at the same time) and GM compatible (so any song or sequence recorded on a GM machine will play back and trigger the correct types of sound on the X3R).

Features

There are three banks of sounds: A, B, and General MIDI. A and B have 100 sounds each, while the GM bank has 136. On top of this, you get two combination banks of 100 locations each. These can be used as multi-timbral setups, so you can assign different sounds to different MIDI channels and trigger them from the X3R's onboard sequencer, or from an external sequencer. With all the sounds within a combination triggered by the same MIDI channel, you can get some wonderful layered effects - more on these later.

Typically, you might also have some of the sounds assigned to different parts of your master keyboard. So you could, for example, have a sax sound triggered by the top third of the keyboard, strings on the bottom third and a combination of the two in the middle - ideal for live performance situations.

Completing the on-board sonics are 114 percussive sounds arranged in eight ROM and four user kits.

With all workstations you get a sequencer to record songs and, more often than not, a disk drive to save and load the sequence data and sounds. The X3R offers a standard 3.5" disk drive and a comprehensive 32,000-note sequencer. A total of 10 songs and 100 patterns may be held in the memory at one time, and tracks can be recorded in real or step time.

Because the X3R was released some time after the X3, Korg managed to iron out one or two of the aggravating niggles found on the latter; most significantly, there are two extra audio outputs on the X3R, making a total of four. This means you have the flexibility of being able to add external signal-processing (delay, compression and so on) to some of the outputs but not others, resulting in a better, more dynamic overall mix.

"The X3R offers a standard 3.5" disk drive and a comprehensive 32,000-note sequencer"

Even without external processing, however, the X3R's mix can be fairly well governed by the panning and mixing facilities within the unit. There are two digital effects processors with a total of 47 effects, and these are all programmable per voice, allowing a very sophisticated mix to be created.

Using PCM digital samples, the sounds on the X3R are crystal-clear and high in quality, if not always mind-blowingly original. The combinations are quite definitely the most inspiring of the sounds with a series of excellent, atmospheric pads which, with just one note held down, will have many Jean-Michel Jarre clones reaching for their record buttons.

Of the programs, the drum sets are the most impressive, incorporating a fantastic array of modern dance, conventional rock and latin percussion. Other programs are less original: you can't help thinking you've heard many of them before and, in fact, earlier Korg keyboards make a better stab at reproducing some instruments - just compare the excellent M1 piano with the rather lacklustre rendition on the X3R.

The 'user interface' of the X3R is easy to use and travel around. Selecting combinations, programs and editing facilities is easy, but once you lift the lid on sound-editing and (in particular) sequencing, the woods begin to thicken somewhat as you find yourself leafing through seemingly endless LCD screens to make the desired changes. One screen and a set of cursors makes for a lot of hard work, although in fairness Korg have also included a set of function keys, to make access to certain pages easier.

The sequencer rewards patient prodding, however, as it is very flexible, offering many of the facilities available on computer-based sequencers such as copying sections from track to track to create songs, looping sections, and so forth. Its ability to read Korg's established '0'-series sound files means you have access to a good sound library.

Summary

The X3R is quite a traditional expander: while many of its combinations and sounds are quite stunning, most aren't particularly original. Its presets have all the musical bases covered, without breaking any new ground.

As a songwriting tool, the X3R is excellent simply because it has a sequencer and disk drive as standard - although the learning curve here is a steep climb, to say the least. But, if you're prepared to get the crampons out and give it a try, you're unlikely be disappointed by its features.

Yamaha TG300

Price: £649 inc VAT

More from: Yamaha-Kemble Music (UK) Ltd, (Contact Details)

E-mu Proteus FX

Price: £610 inc VAT

More from: Emu, (Contact Details)

Korg X3R

Price: £1199 inc VAT

More from: Korg (UK) Ltd, (Contact Details)

You can read about the features, you can check the spec - but there's no substitute for hearing the sounds for yourself. No problem! Tracks 47-53 on this month's Re:Mix provide an array of key patches from each of the modules assessed here, so listen and compare. The sounds are in groups of three, with the TG300 example first, the Proteus FX second, and the X3R third.