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Ensoniq MR

Rack Synth Module By Julian Colbeck
Published April 1996

Expandable and user‑friendly, Ensoniq's new synth module favours preset sounds and effects over editing and programming options. Julian Colbeck asks how the MR Rack stacks up.

The designers at Ensoniq have obviously decided to try for a share of the the Roland JV1080 market with their MR Rack synth. The 1U MR Rack module is expandable in the same way as the Roland, ie. via plug‑in cards with extra sounds, of which more elsewhere in this article (see the 'Expand Your Horizons' box). Even the basic machine, however, offers plentiful, imaginatively programmed sounds, with generous polyphony. Day‑to‑day operation is mostly a breeze, thanks to Ensoniq's SoundFinder, a sort of Thesaurus‑cum‑dictionary‑cum‑Yellow Pages for locating sounds, which really takes the sting out of the MR Rack's small display. Effects are another strong point of the MR Rack, and having Ensoniq's new ESP2 chip on board can only serve to enhance their growing reputation in this area.

To simplify operation, in‑depth sound editing is only possible via a suitable software editor. Mark Of The Unicorn have already released a MR Rack profile for their Unisyn editor/librarian to this end (for more on this, see the 'Programming With Unisyn' box), and other major software manufacturers, such as Emagic and Opcode, are following suit. Fortunately for those who aren't keen on software twiddling, the front panel does allow access to a selection of key parameters.

The MR Rack's GM mode does have a few unruly aspects to it, and although I always got there in the end, on more than one occasion the unit got itself in a right old tizzy and had to be re‑initialised. There's also the question of price. Granted, the MR Rack comes with new Ensoniq technology which has to be accounted for somehow, but the company will have to work hard to persuade the end user that the MR Rack is more than just a slimline sample playback unit, containing another barrow‑load of gassy, dreamy, fluctuating, Wavestastion‑esque sounds. Without the stimulant of price, battle‑hardened customers will need to see pretty dazzling performance before the old adrenalin starts pumping.

Panel Beating

The Wavestation SR makes a sensible comparison, audio performance‑wise, but it's a pleasant surprise to discover that the MR Rack's user interface is 10 times friendlier. The panel is about as direct and complete as a module of these dimensions and this range can hope to be. After the front‑mounted phones socket (use of which doesn't kill the audio flow from the back) and volume pot, comes a group of six mode LEDs which control the instrument's basic operational mode. They allow you to access an individual sound or sound combination, mute sound, control effects, and gain access to global set‑up parameters. They're followed by a pair of Enter/Exit buttons that double as 'part' selectors (an MR combination patch can use up to 16 parts).

The fun really begins with the schizophrenically‑named Parameter/Sound Type knob. In single sound mode, this click‑stopped, continuous wheel spins you through all the various sound types in the instrument: Basses, E Guitars, Pianos etc, or you can alight on ALL‑SND ('all sounds'), whereupon every sound will be listed alphabetically. The Sound Type knob selects instrument category, while the Value/Sound Name knob on the other side of the screen, selects sounds within that category. The screen doesn't only display the category and the sounds therein, but also their actual location, for instance, 'ROM Bank: 112', plus the current Part and MIDI channel.

Dubbed SoundFinder, this system functions in both single sound and combination sound modes, and the savings it affords (in time, brainpower and expletives) cannot be over‑stated. Ensoniq could have left it at that, but the icing on the cake is the Audition button. A momentary control, Audition activates a snippet of appropriate music for each sound or sound category. For example, if you're in the Bass section, simply stab the Audition button, and a couple of bars of groovy bass‑playing let you assess each bass sound from a performance standpoint. You can even reset this to play octaves, a major chord, or arpeggios instead of a few bars of Nile Rodgers. Either way, retail stores will love this. Yet it's not just a demo novelty item. As a labour‑saving device alone, the Audition button lets you spin through and audition sounds without having to continually swerve back and forth between your module and keyboard — in my opinion one of the most tiresome aspects of modern, patch‑packed module life.

Completing the front panel inspection is a green MIDI indicator (which flickered continuously, even when I wasn't playing!), a data card slot and power switch. Meanwhile, around the back are standard MIDI In/Out/thru and two sets of stereo audio outs, Main and Aux. I suppose you can always connect pedals into your controller keyboard, but even so, this strikes me as a fairly basic suite of connections for this price of instrument. Even the Proteus has an input option.

On power‑up, the screen briefly alludes to the 'mister' joke (wearing thin already): 'Just call me Rack, MR Rack' it quips, before settling into a demo sound entitled 'Evolution'. This is a factory default, but mercifully, it can be altered. One's first impression is of ultra‑high audio quality. Making the most of the MR Rack's four 18‑bit DACs, 'Evolution' exudes both bits and programming chops, as it flits effortlessly between muted woodwind, light mist, jangling bells and other assorted ear candy — and all in the space of ten seconds. The instrument's repertoire of demo songs is immaculately programmed, fearlessly highlighting such notoriously difficult instruments to play in MIDI as harp, fiddle, and accordion. Of the MR Rack's ability to selectively pitch‑bend notes within a chord, there remains no doubt.

Playing The System

Resisting the temptation to just bliss out with a cigar and a glass of port, we come to the tricky business of assessment. With 12Mb of waveform ROM on board as standard, the MR's range of sounds is too wide to pigeonhole. A general lushness puts me in mind of the Korg Wavestation, although there are lots of ambient, ravey squeaks, and tinny major sevenths too. I'd say the MR bestrides natural and synthetic instrument camps with near perfect balance.

Its raw material is a 12Mb slab of waveform ROM containing samples, waveforms, and Ensoniq's own time‑shifting 'Transwaves' that form the basis of the MR Rack's Sounds. Access to the full complement of filters, envelope generators, LFOs and so forth is via software only, but a reasonable amount of editing can be achieved using only the front panel facilities.

Sounds are stored in ROM or RAM Banks, internally or on the card. Up to 128 Sounds can be stored in a Bank, a number that is dependent upon the amount of memory the sounds take up. Theoretically, the MR Rack can store up to 128 Banks. Pause here, to contemplate the matter of Bank Select. The MIDI Bank Select message is not yet a standardised command (or, in Roland's case, set of commands), for reasons I fail to understand. Because of this, manufacturers of MIDI patchbays have shied away from implementing Bank Select. While this doesn't pose much of a problem in the studio (because you have the time and technology to access the sounds you need), in live performance it can pose huge problems. This is not meant as a criticism of the MR Rack, but it is something you will have to deal with if you plan to use this as a stage module.

Early Ensoniq keyboards were renowned for their instant stackability, and it's good to see such a feature spreading over into modules.

MR Rack Sounds are single MIDI channel entities. Multitimbrally, the instrument employs Performances that contain 16 Sounds each, slotted into what Ensoniq calls a Part, plus a dedicated effects set‑up. This is fast becoming a standard system, so you won't find it at all complex to understand. A degree of sound editing is available at this Part level. You can tweak a filter, soften an attack, alter the tuning and so forth. Useful as this is, it's important to realise that you are only altering a Sound's appearance within that Part — and only temporarily, until you re‑save it within a new Performance. However, Ensoniq have been thoughtful enough to give you the option of letting the Sound's originally programmed Part parameters come with it, or letting the current Part's parameters take precedence (because, for instance, you might have some weird tuning, pitch, or modulation you want to preserve).

Performances are categorised and called up in much the same way as Sounds. General MIDI is a special type of Performance and, fortunately, there's very little performance (with a small 'p') involved in accessing the mode: hit the System button until you see the prompt, hit 'ENTER For GM!' and you're off. Within each Performance you can also store one 'Stak', which as the name suggests, is where you can stack or layer sounds upon each other. Early Ensoniq keyboards were renowned for their instant stackability, and it's good to see such a feature spreading over into modules.

What is good about the MR system is that the system itself is fairly unobtrusive. You are, for instance, always operating within a Performance even if you have not specifically selected an actual Performance to work in. This is simply how Sounds appear — and it works well. The system is unobtrusive, and it's also flexible, to the extent that you can alter the way the instrument presents itself to you, via a selection of 'WakeUp Modes'. If you only use GM, you can set the instrument to default to GM mode on power‑up. Alternatively, you can set 'Last Selected Sound', Performances, or 'As Turned Off.'

Ensoniq have made a bold decision in not offering complete front‑panel sound editing, but provided you fully understand the consequences editing at the Part level is quite sufficient for most practical purposes. Emu's Proteus offers only fractionally more editing power in real terms, even if you have notionally freer access, in terms of being able to save 'edited' sounds afresh. Admittedly, nobody likes being told they can't do something, especially at this price, but at least Ensoniq programmers were instructed to pull out their Grade‑A programming skills when it came to the factory sounds.

Party Down!

The MR Rack is no Oberheim Xpander in the programming department, but this does not mean you're lumbered with a collection of immovable, immutable sounds. The Part level houses a vast collection of parameters, pertaining not only to control items like MIDI channel, pan, pitch bend response, glide, delay, keyboard range and such, but also quasi‑editing parameters such as LFO rate, depth and delay, amplifier and filter envelope, volume, and tuning. In each camp, you'll find some highly imaginative offers.

Unusually, if not uniquely, there are two pitch bend parameters, one for up and one for down, each operating in up to 12 semitone ranges. A Part can also elect to use Global pitch bend mode, where you then have an additional choice of 'Held' mode. This mode will only pitch‑bend notes that are held down. Notes simply sustaining, or in release, will remain static. It's a trick you need to get used to, but it will let you produce some authentic‑sounding double stopping or internal pitch‑bend effects in guitar, fiddle, or pedal steel style — a nice feature. Alternative tunings are an acquired taste. But if you have such leanings, or are interested in finding out about alternatives to equal temperament, the MR Rack makes the search about as easy as it can be.

Within the PitchTbl= page in Part Parameter, you'll find 30 or so wild and wacky tuning scales, from Java‑Pelog 1‑3 (no, not a trendy blend of coffee but versions of the seven‑tone Pelog scale used in gamelan), a 22‑pure interval Raga tuning, several Chinese and Tibetan scales, Arabic, and some truly awful Greek tunings that make the instrument and you feel drunk. Okay, so this can be fun, and I really appreciated the fact that you have the choice of retaining a new tuning in a Part location (so you can try out different Sounds on a new scale), or simply can the whole idea of alternative tunings as soon as a fresh Sound is brought in. Full marks for this.

Front‑panel parameters that can be accessed include LFO — speed, depth and delay, plus the option of synchronising the LFO to MIDI, and simple envelope stages of attack, decay, and release for amplifier and filter. Filter cutoff can also be adjusted, working as a simple tone control. While it would be wrong to suggest this offers sufficient editing power for everyone, experience and practicality does suggest that these are the types of edit parameters most of us stick to. If you're running an Atari, say, and cannot run an MR‑compatible editor, you can take some comfort in the fact that the sound edit parameters can also be adjusted using Non‑Registered Parameter Numbers (NRPNs). In other words, you can control changes in tone, envelope, and LFO directly from your computer, storing changes within your sequencer. NRPNs can also be used for volume, chorus, pan changes and so on.

Drum De Dum Dum Drum

Somewhat of a similar myth (as in something we like to think we do, though we don't) surrounds drum mapping. You like the way a kit sounds — you use it. You don't — in my experience, you find another one. However, the MR Rack offers detailed selection and processing of drum kits, direct from the module itself. Starting off with a choice of basic mapping — Ensoniq or GM — you can alter the sound that each key will trigger, using not just pre‑selected drum sounds but any which are available. You can alter a sound's pan position, whether or not it will respond to effects, and its tuning.

The MR Rack's complement of drum kits and drum/percussion patches is both wide and excellent. Ensoniq has only relatively recently included GM mapping within its instruments, in addition to its own format. This makes them rather more playable, because sounds are often mapped to two keys and so can be triggered faster. In Ensoniq format, you have seven kits to choose from, and in GM format no fewer than 11. A drum kit can hold up to 64 individual sounds.

In Effect

Built‑in effects are both a blessing and a curse on modern synths, enhancing individual sounds on the one hand, while on the other creating problems when you want to combine effects‑laden sounds multitimbrally. The MR Rack's solution is becoming quite standard: although Sounds arrive complete with their own effects settings, when you take these into a Performance, you'll have to make a decision. You can plump for what Ensoniq call an Insert effect, which is the effects setting from one individual Sound applied to all Sounds within the Performance. Alternatively, the Sounds can remain dry, or they can tap into a global chorus and a global reverb setting.

The effects themselves span parametric EQ to non‑linear reverbs, phaser, DDLs, chorus, flanger. There are also some most unusual offerings, like Chatter Box (a vocalising formant filter that almost gives the effect of a voice box — remember those?), and Formant Morph (similar, but with distortion and less movement). "Yes," I hear you say, "But who wants stuff like this?" Me, for one. You, for another. Dramatic effects like these are simply money in the bank when it comes to producing unusual, stand‑out sounds. Tailor‑made for the charts — for a month or two, at least.

Not only are there plenty of unusual algorithms, but the level of control offered is staggering. On Chatter Box, for instance, you have control over a the articulated 'shape,' the formant warp, auto pan depth, two LFO rates and depths, delay time and level, feedback and damping, plus the amount of signal being fed into the filter. This is great stuff. Use of the MR Rack's effects merits a specific article in itself, but I had to ask the Ensoniq marketing team how they justified offering such detailed programming in areas such as the effects and drum mapping, while restricting the onboard sound programming. Apparently, their market research has revealed that of those Ensoniq users who are interested in detailed sound design, the majority will have access to a computer for software editing. Items such as effects and bespoke drum kit building are valued more as onboard, post‑production facilities.

The nature of the effects, and the way that the MR Rack is set up does produce one initially disconcerting feature; namely the short gap between a new Sound being selected and that sound appearing. This only occurs, says Ensoniq, if you continually select a new Sound within the same Part. True, but isn't that what most people will want to do? Still, this blip shouldn't detract too much from your enjoyment of this instrument.


The MR Rack is a very tasty unit. It's well‑thought out, generally easy to use, sounds terrific, and has enough innovative features to make it exciting both to play and listen to. I did encounter some oddities in GM mode: parts disappeared on some sequences, and the pitch bend ranges went squiffy on others. GM is not an exact science, and I also fired in some GM SMFs that were real killers.

Roland's JV1080 is probably the closest the MR rack has to head‑to‑head competition, and has the obvious GM advantage of being made by Roland. Nevertheless, the MR Rack has, I feel, more interesting sounds than the Roland, while Korg's are suffering from a degree of over‑exposure. Buying an Ensoniq is not the risk it was a few years ago, and now could be just the moment to jump in.

Programming The Mr Rack With Unisyn

As mentioned elsewhere in this review, full MR editing is only possible via software. Although MR Rack editing modules are currently in development for Emagic's Sound Diver and Opcode's Galaxy, the only module available now runs with Mark Of The Unicorn's Unisyn, available for Macs and Windows PCs (see review, SOS Dec 95). In the States, when you return your MR Rack registration card, Ensoniq, not MOTU, will send you a cut‑down version of Unisyn, along with a 'Profile' (layout and set of instructions) pertaining to the MR Rack. If you're sold on the program, you can (for a modest charge) upgrade to full Unisyn status, whereupon you'll receive Profiles for pretty well all major instruments/manufacturers. Be warned, however, that this arrangement does not apply in the UK!

Armed with Unisyn, the MR Rack becomes a fully programmable synthesizer in the S+S mould, tapping into the 12Mb of keyboard, string, percussion instruments, analogue‑style waveforms, inharmonic waves and transwaves, and more. Unisyn is a clean‑lined, logical editor, thankfully free of frills; you're simply given a series of pages with sliders and pots you can manoeuvre as if you were being presented with a hands‑on synth front panel.

Unisyn's extensive librarian duties are somewhat upstaged by the excellent housekeeping of the MR Rack itself, but the randomising facilities are fun, and the whole big screen package is wonderfully clear and simple to use.

Ensoniq would like it known that the availability of the Unisyn package should not deter programmers from producing dedicated MR Rack editors, especially in Europe, where the Atari is still widely used. Pockets of Atari‑dom do exist in the US, but the platform is regarded in the same light as, say, users of manual coffee grinders, or people who bake their own bread. You know, a bit weird.

Sound Types

Categories in which Sounds exist ex‑factory, and under which they can be located using the SoundFinder system:

  • Bass
  • Bass (Synth)
  • Bell
  • Brass (Section)
  • Brass (Solo)
  • Drum Kit (Ensoniq)
  • Drum Kit (GM)
  • Guitar (Acoustic)
  • Guitar (Electric)
  • Hits
  • Keys
  • Layers
  • Loop Grooves
  • Mallets
  • Orchestral
  • Organ (Acoustic/Pipe)
  • Organ (Electric)
  • Organ (Layers)
  • Percussion (Kit)
  • Percussion (Solo)
  • Piano (Acoustic)
  • Piano (Electric)
  • Piano (Layers)
  • Plucked
  • Sax Solo
  • Sound FX
  • Splits
  • String (Section)
  • String (Solo)
  • Synths (Poly)
  • Synths (Mono)
  • Synths (Pads)
  • Synths (Vintage)
  • Synths (General)
  • Vocals
  • Wind/Reed

Each Sound Type holds many individual sounds, far too many to list. Here are some thoughts on key, or particularly noteworthy ones:

    This is a beautiful sound, offering plenty of edge when you dig in, but otherwise quietly classical and expansive. It has exceptionally smooth sample cross‑overs, and one of the most natural responses to progressive increases in velocity I've ever come across. The decay tapers naturally, too, over a 13 second period, with no noticeable degradation. Okay, so my Broadwood acoustic decays for over 40 seconds but... [Stop bragging — Ed].
    A real treat for Byrd(s) lovers. Electric, but not electronic.
    Light and jazzy, and highly playable with a delicious repeat.
    Twangs like a giant elastic band and sounds brilliant.
  • STEEL PAD (a layer)
    A rich and seductive amalgam of soft synth and what sounds like bazouki. Thins out beautifully as it goes up the scale.
    A string section that rivals the classic Noble Strings patch on the Wavestation.
  • RAVE M7Maj7
    One‑finger chord stabs you hear every day on the radio. Tinny, nasty; perfect.

Expand Your Horizons

A synth that cannot be updated or uprated in some way would be dead meat today, say the marketing experts. The MR Rack's Expansion Board options do look good, with three slots available, adding up to a potential total of 84Mb of waveform data. Expansion cards range from 8Mb to 24Mb, and rejoice in titles such as as World Instruments, Pianos, Dance/Hip Hop and Drums. Ranging from 8Mb to 24Mb, they come with a complete pack of new Sounds and Performances, and are expected to cost from £200.


  • First‑rate sound selection process.
  • Yummy effects.
  • Expandable.


  • No controller inputs.
  • If you're the kind of sound designer that likes to get to the bottom of things, the lack of full front panel editability may bother you.


A controversial instrument with its brave stance on editing, but if you like driving a car more than working on it, you'll find this the Austin Healy of synth modules — fast, sporty, and a lot of fun.