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Emu Procussion

Sampled Percussion Performance Module

What is it about programmed drum parts that make them sound programmed. Paul Wiffen goes in search of the secret of realistic drumming, and finds it in the Emu Procussion.

Drum sounds... these days they emerge from virtually every MIDI device on the market. Gone are the days when the drum sounds available to the musician were limited to the single bass drum, snare, hi and lo toms, open and closed hi-hat, and the odd percussion sound from his/her drum machine, and adding any more involved all that tedious mucking about opening the machine and changing the chips inside (it seems like only yesterday!).

Nowadays you turn on a £250 portable keyboard and monster drum sounds issue from it. Workstations ooze with different kits; even some sequencers that can't play any other type of sounds have the ability to trigger internal percussion sounds; and if you trigger the demo sequence of the average modern drum machine you barely have time to get used to one set of sounds before it has gone through a bewildering variety of kits and you can't remember which you liked and which you might be able to use.

So do we really need another box chock full of percussion sounds? Well, if that was all Procussion had to offer, I would probably have to say no, however great the range and power of its sounds. But what Procussion is actually offering is something much rarer: the ability to create drum parts that sound like drum parts. Let's face it, with the wealth of drum sounds that are available to the musician these days, 9 out of every 10 records on the radio use sampled drum loops rather than individual sampled sounds. Why? Probably because somewhere back in the dim and distant past, a drummer actually played his instrument(s) and injected the original track with a modicum of that rare commodity, 'feel' (or 'groove' if you prefer — never liked the term myself).

So rather than try and create something so elusive and ephemeral themselves, producers, rappers and songwriters (there are some left, aren't there?) prefer to grab it from somewhere else.


Procussion is not actually the first instrument to move in this direction. There have already been brave attempts which have tried to place as much emphasis on the ability to create 'human' percussion parts as on the humungousness of their sounds, and they have met with some success. For all its failings, the Linn 9000 must be credited with some of the first advances in this direction. The torch was then picked up by Sequential with the Studio 440, and perhaps the ultimate product of this school of thought was the Akai/Roger Linn MPC60, a machine which I never really rated as a sequencer, but which in the hands of a drummer produces drum tracks of breathtaking realism.

In terms of drum machines pure and simple, the Roland R8 and its descendants unquestionably merit their classification as 'human feel' machines.

However, I suspect that the majority of music today is made without the help of such splendid machines (or at least it sounds that way), and I think the reason for this can be traced to the centrepiece of the average MIDI set-up these days: the computer sequencer. The machines I mentioned above tend to perform at their best when the drum parts are created and played back from the machine's own sequencing facilities. What is sent out over MIDI, or the response to what is received at the MIDI input, tends to be a mere shadow of what is possible internally. I have on many occasions tried to use via MIDI percussion parts played or programmed by percussionists, either to trigger a drum machine's sounds from a sequencer rather than from the machine itself, or to assign the parts to better quality sounds — the character and life of the track seems to disappear completely from the parts, even if the sound quality is improved.

Don't get me wrong, I am not criticising the abilities of the computer sequencers involved. There are many fine sequencing programs available which in themselves can impart grooves or feel to percussion parts. The problem is that many of the nuances that make a percussion part sound human have no standardised coding for transmission over MIDI. In fact, MIDI (which I always felt should have been called KIDI anyway — Keyboard Instrument Digital Interface) serves the percussionist less well than any other instrumentalist, with the possible exception of the Balkan Nose Flautist.


To start with, the artificial assignment of MIDI Notes to percussion sounds has always been a minefield, hence the proliferation of remapping facilities within sequencers to get round this. Another problem arises from the numerous ways a drum can be hit, which can only be dealt with by making separate samples and assigning them to completely different keys. Add to this the fact that timing variations, generated either by too much MIDI data being sent down one cable or by a slowness in the receiving instrument to act upon that data, stick out like a sore thumb on percussion parts whilst they will often pass unnoticed in most other areas, and it all adds up to a pretty sorry state of affairs in the percussion department.

Of course, it is perfectly possible to slave your sequencer to your human feel drum machine, and there are probably people out there doing just that (slaving the drum machine to the sequencer often has the same effect as recording the data via MIDI), but that tends to go against the modern trend of doing everything from one central point. And what do you do if you are really bucking modern trends by triggering percussion parts live, and so a sequencer of any kind doesn't figure in your set-up?

What seems to be required is a module which, although it doesn't feature any sequencing capabilities (so as not to compete with the all-powerful computer sequencing god), is nonetheless capable of processing the incoming MIDI data to produce exactly the humanisation we are talking about. This would make it equally effective with live performance MIDI data or that arriving from sequencers.

Enter Procussion ('ah', they cry, 'we wondered when he'd get around to that'). For Procussion is not just a Proteus with amnesia (the casing is identical) that has learnt to produce drum sounds instead. It has a completely different operating system, which allows you to determine just how the percussion sounds will react to the incoming MIDI data. And for me, this is Procussion's raison d'etre, excellent though the drum sounds in it are.


The 4 meg of ROM in Procussion (same as that in the original Proteus, allowing another 4 meg to be added at later date) contains 140 samples, plus 80 single-cycle waveforms which can be used to add pitched elements into stacked sounds. The samples include 12 bass drums, 26 snares, 6 toms, 10 hi-hats (in various degrees of openness — or is it closedness?), various crash and ride cymbals, plus all the various other percussion devices you have ever heard of (congas, guiros, cabasa, shekere, etc.), quite a few that you haven't (Tumba or Hembra?), and some bass sounds to round things off. These can be used to actually play basslines over a keyboard range, as could the various standard single-cycle waveforms (sine, triangle, square, sawtooth) and not-so-standard single-cycle waveforms (Fuzzy Gruzz, Duck Cycle 2) that are in ROM.

It might seem at first that Emu would have been better off providing some more drum samples instead of all the synthesis-style waves, until you consider that all the single-cycle stuff probably only occupies the same amount of ROM as one drum sample. It is also worth bearing in mind that most of the electronic drum sounds that have now entered (or re-entered in some cases) the modern drum vocabulary were generated using just such building blocks. It is much more efficient in terms of sample memory to provide access to such electronic percussion sounds in this way than to fill the ROM with sampled recordings of them.


These ROM drum sounds differ to those found in any other drum machine or brain that I have ever come across, in that they are not intended to be used as final sounds (although some of them could well be) — they are but the raw data out of which to build the final sounds. Procussion's unique approach is to combine these sounds into more complex ones using its stacking architecture, which is completely different to that of the Proteus which spawned it.

One of the features that Procussion does inherit from Proteus is critically important for a percussion module, particularly in view of the way this module builds up its sounds — its polyphony. 32-voice polyphony is vital in a machine which is able to stack lots of samples together to build huge drum sounds. Many a time I have put lots of drum samples together on expensive samplers to make a Drum Kit Of Doom, only to find that the bass drum was cutting off the snare because there wasn't enough polyphony to play bass, snare and hi-hat together. No chance of that here — even if you stack together four sounds on each key you still have 8-note polyphony, more than enough for the busiest drum part.


Stacking is one of the features that makes the Procussion sound huge, and it is also responsible for its flexibility and sonic complexity. Some of the sounds are pretty big on their own, but put a few of them together and you can really make ears bleed! Each patch in the Procussion, referred to as a Kit, can have eight Stacks within it. Each instrument layer in the Stack (there can be up to up to four) can be given its own coarse and fine tuning, volume and pan position, as well as a delay time, and pitch and alternative amplifier envelopes.

This means you can balance the levels of the four sounds, perhaps to add a hint of one sound to another, or to combine several sounds at equal volumes then alter the tunings — coarse, to give the different components separate pitches, or fine, to bring in phase/chorus effects from de-tunings. You could delay some elements to create echo-type repeats, and even alter the pitch and volume during the course of the sound. I'm trying to avoid cliches like 'the possibilities are endless', but it has to be said that this degree of percussive sound design control is unique.


However, complete though these parameters are, they are nothing compared to what can be achieved once you start to use the modulation available. If you can stand the listings, sources include: velocity; trigger tempo (which needs a section all to itself, as it is where much of the humanisation and feel I was alluding to earlier can be programmed in); random; pressure; pitch; key positions; wheels; and any other MIDI continuous controllers (up to four, set globally). And if you think that's a lot, there are three times as many destinations, including overall or individual layer pitches, volumes (and their respective envelopes), accents, attacks, decays, sample starts, pans, holds and filterings, plus LFO rate and amount.

Needless to say, as in any system with this many possibilities, the brain needs time to accustom itself to the way in which sounds are created, so Emu have thoughtfully provided 550 factory Stacks for you to be getting on with while you learn to build your own sounds (there are a further 512 locations for user Stacks). If you think of each of these as the equivalent to a sound in other percussion sound generators, you will see the sheer size of the percussion palette Emu are giving you, before you even begin to make up sounds of your own.

"Never before has so much thought gone into making MIDI percussion so responsive, so flexible, and so frighteningly realistic. I kept expecting Procussion to swear like a drummer or try and steal my girlfriend when it got drunk."


The factory Stacks are organised and grouped into 64 factory Kits, but of course you can use any of the factory stacks to build up your own kits in the 64 user memories.

The sheer breadth of drum sounds in Procussion is demonstrated by these Kits. All musical styles are here, from the huge sounds of Stadium Rox and Mega Drums (for BOFs like myself), through the up-to-the-minute House Machine and Hip Hop, to the classical in Orch Perc and the twiddly in Jazzy Traps. Even those Kits which don't appeal, one has to grudgingly admit, are completely authentic for the music they are designed for, eg. Country Kit, Disco Ball, Rockabilly. If your regular gig is playing those styles of music, the punters won't be disappointed. For sheer hooligan value, you can't beat Heavyosity, Thundadome and Heavy Metal. My neighbours have to be saints not to have complained when I got started on those!

Kits like Huge Room and Ambient Rock had me checking the specs to see if Emu hadn't slipped in some signal processing while no-one was looking, but it was all done by mixing samples of drum reverb and ambience (separate sounds in the ROM) in with the drum sounds themselves, making me aware of yet more potential for the stacking and modulation system than I had already worked out for myself. Which reminds me: I shouldn't spend all my time listing factory presets, which I know you are only going to use for the first couple of weeks till you get your own unique sounds going (?), but instead get back to describing the architecture of the system and how this increases the potential for authentic performance.


Much of this potential comes from the unique Trigger Tempo modulation source, which I tantalisingly mentioned earlier. Now it's time to look at it in greater depth. The principle behind this facility is that in acoustic drumming when the same drum is hit more than once in quick succession, it sounds different on the second or third strike, particularly if the successive strikes are not played with the same hand (as in a snare drum roll or a tom fill). On Procussion, any multiple hits in quick succession can be modulated so that subtle (or not so subtle) variations can be introduced to better represent what happens in the real world.

Once the Trigger Tempo has been set, to match the tempo of the song you're working on, then any repeat triggers of a MIDI note which has Trigger Tempo set as a modulator that fall within the time interval of one beat at the tempo set will have the assigned modulation brought in. You can set this modulation up so that a completely different stack is triggered, or so that any of the modulation destinations we saw earlier can be affected.

This relatively simple parameter allows all sorts of authentic drumming characteristics to be set up — so a backbeat snare which would normally be played with one stick can remain constant, but when a snare roll comes along an alternating sound (or variation) is introduced. As Trigger Tempo can be routed to lots of different parameters, the effect can be as subtle as a slight change of volume, filter or pitch in one of the stacked sounds, or as drastic as you care to make it, with completely different sounds.

This parameter can also be used to simulate hitting a different area of a drum head, different degrees of openness in a hi-hat, different pitches in a set of tom-toms, and I'm sure many other typical drum attributes which a humble keyboard player like myself can only imagine. One thing is for sure — when I was playing the factory Kits from the keyboard, even I sounded more like a drummer than ever before.

Procussion's manual explains very clearly how this brand new parameter works, and how to use it, but I ought to also mention a second document included with the review machine, called Pro Tips. This explains in layman's (ie. non-drummer) language why certain things happen in drum performance, and how to recreate them in a very logical step-by-step manner on the Procussion. If you've ever wondered why your drum parts sound wooden, make sure you get a copy of this from Emu.


Another area that Pro Tips goes into (also covered in the manual) is what our American cousins seem to refer to as 'rip-offs'. At first I wondered if Procussion could protect me against unscrupulous salesman, but it turns out to be a problem that I have often noticed with drum machines in particular. If a note is retriggered before the first one has died away, then the first sound is abruptly cut off so that the new sound can be played.

This can be a problem even in instruments which have plenty of polyphony, because the re-triggering often uses the same voice in the machine's hardware. Procussion deals with this by letting you specify, in more detail that I have found in any MIDI keyboard, let alone a percussion module, just how the polyphony is assigned.

If you want, a single repeated note could use all 32 voices, or just eight or four, or you can choose to fix a sound's polyphony to 'mono' so that you can deliberately cause exactly the effect described above (very useful with hi-hats). But it goes much deeper than this: you can set the polyphony assignment so that layers within a stack do or don't choke themselves and/or other layers off. I spent ages playing with this particular parameter and found it incredibly useful. Can I get this on a synthesizer please - and quickly?

There are many other extremely well thought out aspects of Procussion's operating system about which I could wax lyrical for hours, but as space is limited I had better give you a brief summary of them.

Hi-hat realism reaches new levels when you assign a MIDI continuous controller (volume-type pedal or mod wheel for example) to govern the opening and closing. Clever filtering can vary the tone of cymbals so that the same set of frequencies isn't simply regurgitated every time the cymbal is triggered. Velocity control of filter (or tone as it's called on Procussion, so as not to confuse drummers unused to synthspeak) means that higher velocities increase brightness, and not just volume as on most drum machines.

Velocity scaling maps allow customisation of Procussion for different MIDI controllers and to different playing styles. In fact, everywhere you look, Procussion goes that extra mile for authenticity. But this need not dismay those crazy experimenters out there. All these parameters allow the sounds to be messed up more than ever before, so if a snare drum rising in pitch and turning into a reverse cymbal via velocity is your idea of the ultimate drum sound, Procussion's still for you.

The mix and output facilities are very similar to those of Proteus, but for those whose paths have not crossed that of Proteus yet (you poor souls), here is how it works. Any sound can be sent to the main stereo outputs (which automatically sum to mono if only one output is connected) or to either or both sides of the two stereo sub outputs. These can then be sent to external effects (if the sampled ambiences available in the machine aren't enough for you) and then (if required) by devilish cunning brought back into the main stereo output mix via the ring of a stereo jack plugged into the sub output sockets (a facility many Proteus owners have yet to discover because they haven't read their manuals). How many other MIDI modules can boast two stereo returns?


To my ears Procussion seemed to trigger right on the nose every time, giving the lie to those who claim that MIDI is just not fast enough for percussion. More importantly (I mean, what do keyboard players know about such things anyway?) a drummer friend expressed the same opinion on hearing Procussion, albeit slightly more colourfully. It does however seem a shame that those who still cling to this idea about MIDI (usually because their attempts to use it have not followed certain basic principles like putting timing critical parts on MIDI channel 1 or even on a separate MIDI output bus) will not give themselves the chance to avail themselves of Procussion's glorious realism simply because there are no analogue trigger inputs. I guess there was no more room on the back of the unit for half a dozen trigger inputs. My advice to real drummers is get yourself a trigger-to-MIDI convertor, fast!

So is the lack of analogue trigger inputs really the only ghost of a criticism in this review? Well, I looked very hard for other omissions or flaws, but I'm damned if I could find them. Other reviewers have whinged about the lack of RAM or ROM card slots for more source sounds. Personally I always hated these things. They get lost, or people nick them, the sounds you want to use are always on different cards and there aren't enough slots to have them accessible at the same time, they cost a fortune per sound... the list is endless. If I want extra sounds, I want them inside the machine where they can't suddenly disappear. I'm with Emu on this one. Give me expandable internal ROM every time.

No — I'm sorry to disappoint the fans of the Wiffen carve-up job, but I could find precious little to criticise and much to praise in Procussion. Never before has so much thought gone into making MIDI percussion so responsive, so flexible, and so frighteningly realistic. I kept expecting it to swear like a drummer or try and steal my girlfriend when it got drunk. It sounds great, but in this respect it has many rivals. More importantly it plays great, and here it's in a class of its own. Now, the only question is: can I replace all the drum parts on everything I've ever recorded before they ring up to ask for the review model back?


£699 inc VAT.

Emu Systems, (Contact Details)

Also featuring gear in this article

Previous Article in this issue

The Max Factor

Next article in this issue

MIDI Mixing Made Easy

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Jul 1991

Gear in this article:

Drum Module > Emu Systems > ProCussion

Gear Tags:

Digital Drums

Review by Paul Wiffen

Previous article in this issue:

> The Max Factor

Next article in this issue:

> MIDI Mixing Made Easy

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