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Rossum Electro-Music Morpheus

Eurorack Module By Paul Nagle
Published June 2017

The E-mu Morpheus was a remarkable synthesizer crammed into a 1U rack, awaiting (although we didn’t know it at the time) future rebirth of its best bits. A Morpheus owner myself, I’ve eagerly awaited the Eurorack version of its filter since the announcement... and now it’s here!

Size: 18HP. Current: +12V = 135mA. -12V = 25mA.Size: 18HP. Current: +12V = 135mA. -12V = 25mA.The Morpheus filter — or, to give it its full title, the Morpheus Stereo Morphing Z-Plane Filter — has 289 Cubes as its foundation. A Cube consists of up to eight frequency response configurations, helpfully visualised as movement inside a 3D cube on the pin-sharp OLED screen. The display is loaded with vital data yet manages never to feel cluttered — and has a screen-saver that’s invoked automatically after a user-customisable period.

Half a dozen sturdy knobs are grouped together, sadly too closely together for comfortable use. These are the Frequency, Morph and Transform controls, each with attenuverters and CV inputs. Depending on the filter selected, Transform can become Distortion, in which case the on-screen graphic T switches to D. A single encoder adjacent to the screen is used to select filters or filter sequences, confirm actions, navigate the filter edit menu, and so on.

The original Morpheus was capable of real-time morphing in just one dimension, but today’s processors have much more power and can therefore offer 3D morphing — and in stereo. When using CV input, this produces some truly remarkable effects way beyond its illustrious ancestor, although audio-rate modulation often proved too taxing and unreliable.

Even though I’m an old hand with E-mu’s Z-Plane filters, the sheer variety presented here made exploration a daunting task and one not to be rushed. Initially, though, eagerness got the better of me and I loaded in one of the filter sequences — 15 are set up already, with names such as Flangers, EQs, Synth Filter and so on. For convenience, you can store up to 200 sequences with a grand total of 20,000 entries dynamically allocated between them. It could be a more useful way of assembling a number of favourites, say for a live performance.

Having picked a sequence of filters, I chose a sawtooth waveform to be processed and a trio of LFOs to drive the three CV inputs, also connecting the reset output of an LFO to the ‘Inc’ input. Inc makes it possible to automatically select the next filter in the sequence and therefore, without any further hands being necessary, I was able to audition each filter stored in the sequence while three parameters were swept by the LFOs. A user option sets the transition time between filter changes, but it’s worth pointing out that this doesn’t always lend itself to smooth rhythmic use; it can work effectively, but whether you escape pops and glitches is highly dependant on the filters chosen.

Actually, this was entirely the wrong way to start learning the Morpheus, as I quickly realised. It would also be a mistake to begin by simply flicking through the long list of filter cubes and expecting meaningful results from a single source. There is a lot of complex magic under the covers which causes a huge variation in the response, levels and tendency towards distortion in each filter. A far better way to ease your way into this module is to manually dial up each in turn, perhaps referring to the notes in the (excellent) manual. In all cases you’ll benefit from trying a range of sources and different input levels to discover the sweet spots and most suitable modulation partners.

To give you an idea of what you’ll be taking on, there are almost 300 filters to audition with memory locations for a total of 1000 for when you begin tweaking the parameters and storing your own variations. It makes sense to spend a few days with each type but even the list of these is quite long. It is: Flangers, Dipthongs, Standard Filters, Equalisation Filters, Complex Filters, Distortions, Vari-Pole Filters, Tracking Filters, Parametric Tracking Filters, Harmonic Shifters, Vocal Formants, Instrument Formant Filters and Miscellaneous!

At the risk of labouring the point, that’s a hell of a lot of filters in a single module. Even after several weeks of joyful exploration, my personal highlights still change on a daily basis. Hopefully, by mentioning just a few, you’ll get an impression. Starting in the first group, ‘Flange 6.4’ is a deep and highly resonant flanger that responds beautifully to the gentle sweeps of an LFO. Plucking an entry from the Dipthong filters, ‘AOLpParaVow’ is a rich, almost alive filter dispensing moving vowels with a low-pass filter taming some of the distortion. There are a host of analogue-sounding filters to grapple with, but one I’ve returned to repeatedly is simply named ‘Vintage’ — it’s a very credible low-pass filter that you can easily forget originates in software.

Amongst the Distortion filters, I’m a big fan of ‘PoleCross.4’ for its peaky but warm distortion; it’s stunning on drums, drum loops and anything that benefits from extra emphasis. ‘Cube 225’ is a wickedly good phaser ideal for adding swooshiness to pads and polyphonic textures. Next up, probably the most distinctive and instantly impressive tech from the original Morpheus were the formant filters; here C231 or ‘VowelSpace3’ offers amazing variety; it’s able to morph ‘oo’s into ‘ee’s and ‘ah’s to ‘ae’s depending on the levels of Frequency and Transform.

I mentioned that the manual often supplies hints for optimum sources, but experimentation yields stunning discoveries too. In trying to compile a list of favourites, one that caught my ears was C210 ‘HarmTracker’. This produced a stunning stereo hammered dulcimer from a Mutable Instruments Rings module (in its string mode), with a variable decay envelope driving the Transform parameter.

How to sum up a module with so much depth? Well, great expectations can often lead to great disappointments, but not in this case. The Morpheus filter more than lives up to its promise and supplies enough variety to keep even the most ardent explorers and sound design nuts engrossed for months, probably years. Indeed, the main problem I can foresee is keeping track of favourites and remembering which sources worked well with each filter.

Published June 2017