Creative synthesis is set to make a comeback with E-mu's latest sound module. Simon Trask previews the shape of things to come...

Few would disagree that the excitement has gone out of new synthesisers. The continued dominance of sample-based subtractive synthesis and synthesiser workstations at the expense of experimentation and originality has begun a spiral into what some believe is terminal decline. What synthesis badly needs is an instrument which will excite jaded musicians weary of the latest subtle variation of a variation.

Cue Morpheus, the intriguingly-named new sound module from E-mu. While users of the company's Proteus and Vintage Keys modules will find much that is familiar on the new instrument, Morpheus is far from being yet another sample playback machine. To date, all the changes small and large in synthesis have taken place at the sound source stage, from the introduction of digitised samples and waveforms to attempts to 'disguise' those sounds (eg. Roland's Differential Loop Modulation and Korg's wave sequencing and waveshaping). Even Yamaha's FM synthesis was revealed as an attempt to rethink the sound source when the company introduced filtering on the SY77; the company's subsequent abandonment of FM and retreat into sample-based synthesis has not helped the synthesiser's cause.

Now E-mu have done what no other manufacturer has seen fit to do, namely rethink the filtering stage of the traditional subtractive model of synthesis. The result, to judge from an afternoon's encounter with a pre-production Morpheus, is an instrument with unique sonic capabilities. My first impressions are that this is an instrument which many musicians will want to slot into their existing setup - so E-mu's decision to package it in the standard 1U 19" rackmounting format is probably a wise one, although the familiarity of the packaging does rather disguise the originality of what lies inside.

The easiest way to understand how Morpheus's filtering works is to visualise a cube (see accompanying diagram). At each of the eight corners of this cube is a different filter 'frame' (a 'snapshot' of the filter settings - effectively a timbre). Essentially, Morpheus is able to interpolate filter parameter values between different frames on the 'x' axis ('width') in response to note number, the 'y' axis ('height') in response to velocity, and the 'z plane' ('depth') during the course of a note's duration. Interpolations on the 'x' and 'y' axes ('transforms', to use E-mu's terminology) could be described as 'one-shot' - a single set of parameter values generated in response to a note number or a velocity value. However, interpolation on the 'z' plane is continuous, ie. Morpheus generates continuously-changing filter parameter values during the course of a note.

Morpheus' most characteristic sounds derive from this continuous interpolation between two filter frames - hence the description 'Z-plane synthesis'. E-mu draw a parallel with video morphing, the visual effect made famous by Terminator II, Michael Jackson's video, and countless TV adverts - hence the module's name, Morpheus.

But what really puts Z-plane synthesis on another, erm, plane is the actual makeup of the filter frames. These consist of eight 14-pole filters which can be configured as AllPole (seven second-order low-pass filters in series) or Low Pass + Parametric Equaliser (one 2-pole low-pass filter with resonance; and six parametric equalisers each with centre frequency, amplitude and bandwidth parameters). With this sort of filtering power, a whole lot of timbral twisting can go on!

Another important synthesis feature is the Function Generator, an 8-segment modulation source which can function as an LFO or an EG but is much more programmable than either. As well as having its own level and time parameters, each segment can be assigned any one of 61 shapes (including linear, exponential, random and chaos!), and can be programmed to jump to any other segment based on a certain programmable condition. One possibility would be to create a repeating 7-segment envelope with a jump to the 8th segment on key release.

Morpheus doesn't sacrifice more familiar functionality in order to attain its new capabilities. Consequently you've got 32-voice polyphony, 16-part MIDI multitimbrality, Presets with primary and secondary voices (each of which can transform and morph independently, with its own set of filter frames), plenty of modulation possibilities, and the ability to stack multiple Presets (up to 16 of 'em, in fact). Production models will also have onboard effects processing (absent on the pre-production version).

Anyone searching for new, adventurous sounds should give E-mu's new module a listen. The sonic possibilities are plentiful and exciting, though I suspect that E-mu and third-party programmers will have to do most of the sound creation work if they really want to make Morpheus a success - it doesn't look to be an instrument which will encourage the average musician to get into programming. If E-mu can get the sounds right, Morpheus will become hot property.

For further information contact: E-mu UK, (Contact Details). Price £tba