ANYONE WHO HAS heard E-mu's Proteus will appreciate that the sound quality is excellent, although as MT's original review (November '89) observed, there were good sounds waiting to be discovered. Well, a company called Invision have looked at the available selection of tones and added a complementary selection of 70 in the form of their Protologic expansion board.

For those of you not familiar with Proteus' architecture, the structure of the original Proteus is in terms of Tones and Presets. A Tone is a complete sound mapped across the keyboard, while a Preset incorporates two Tones (Primary and Secondary) and various envelope and other programming aspects. The original Proteus contained 125 Tones and 128 Presets in ROM with an additional 64 presets in RAM. The Protologic expansion adds a further 70 Tones including rock organs, electric piano, various synths, fretless bass and 35 keyboard layouts of percussion instruments. Percussion was one particular area in which Proteus was lacking; now it includes bells, steel drums, tablas and looped cabasa, shaker and tambourine. Needless to say, the omnipresent TR808 drum machine sounds have also found their way into the action. So, with the Protologic board installed, a Proteus now holds 195 Tones and 256 Presets in ROM, and will address a further 256 Presets in RAM for you to program yourself.

The quality of the new sounds and their looping is generally very good although you can occasionally hear the modulation caused by crossfade looping. Very few looping glitches are apparent, and the bass end is in keeping with what we have come to expect from the Proteus - the speaker cone-blowing variety.

The Presets in the version under review were not necessarily the final set, but I feel certain that most of them will stay. Some ingenious programming has gone into these - using aftertouch on the 'Fretless Bass' (Preset 12) for pitchbend and the secondary Tone to bring in harmonics at the top end, for example. In fact, 'Fretless' is typical of the usability of Protologic's sounds.

'Performance Guitar' (Preset 8) has tremolo introduced via aftertouch, but uses the modulation wheel to mix in the Secondary Tone of feedback - this is great for those closet guitar heroes amongst you. Similarly, 'L.Guitar' (82) lets you add a fifth by using the modulation wheel - use the wheel for those power chords and then get back to the serious business of soloing without it.

There are also various synth Presets which have a light, metallic nature - like 'Metal Voices' (10) and 'Vector Pad' (27). Only when you look at the Preset information do you realise that Presets sounding completely different often use the same Primary Tone. This is possible because mixing in a Secondary changes the complexion of the sound. For instance, 'Pop Brass' (14) is a mixture of sax section and brass tones while 'Hot Brass' (46) uses a synth and natural brass mixture.

The original Proteus Presets had a good acoustic piano but no electric equivalent. Protologic changes that with 'Electropiano' (35), an ideal sound to record. Meanwhile, 'Dynamic EP' (17) uses two similar Tones, except that the Secondary adds a "twinkle" to the sound at high note velocities. Some Presets use a mixture of original Tones with the new ones. 'Hard Fretless' (34) uses the attack of the existing bass guitar Tone mixed with the new fretless Tone to create a thudding, warm rock bass.

'Echo Drums' (59) makes the Proteus sound as if it has internal reverb - which, of course, it hasn't. Instead, the effect of an early reflection is achieved by using the same keyboard percussion mapping for the Primary and Secondary Tones, with the latter having a lower volume, different pan and a clever bit of enveloping. These really are excellent drum sounds. Another sound worthy of mention is 'VocaloozPad' (72), which is a breathy human "ooh" but without being lightweight. In fact, none of the new presets can be accused of being lightweight; 'Vocal Drums' (73) mixes short "oohs" with a drum mapping while 'Hammond B3' (7) is exactly what it says - a dirty, unmistakeable Hammond with aftertouch bringing in the tremolo.

The cost of the Protologic board may, at first sight, appear high, but you should realise you're adding an extra four Megabytes of memory to the Proteus. But perhaps the best news of all is that Invision are not only offering these 128 Presets for the Protologic board, they're also programming several hundred more for later distribution. Opcode are writing an update to their Proteus editor to incorporate the board, and this too will probably be sold with more Presets.

Price £449 plus £50 fitting charge.

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