Looking for more drum sounds? Yamaha's RM50 packs 500 assorted drum voices (with space for over 1,000) into an appealing 1U rack unit and throws in six external trigger inputs for good measure. Derek Johnson gives it a good thrashing!

Despite the increasing number of drum sounds available on modern synths, especially those of the 'workstation' variety, many musicians still turn to drum machines for their percussive needs. This is no doubt due to the often wider variety of sounds available from a dedicated drum box, but also, perhaps, due in part to the attitude that a synth should be a synth! Hi-tech manufacturers have taken note of this phenomenon over the past few years and responded with sound modules that provide only percussion sounds. Roland's highly-regarded R8M springs immediately to mind, along with Emu's classy Procussion module and the Alesis D4. I suppose it was only a matter of time before Yamaha entered this particular fray — which brings us to the RM50 Rhythm Sound Module, a source of all things percussive, aimed not only at MIDI musicians but drummers too; the latter breed will be attracted by the inclusion of six trigger inputs, allowing sounds to be triggered by a variety of external, non-MIDI sources.

THE LOOK

The front panel of the 1U-high RM50 bears a very strong resemblance to that of Yamaha's recent sound module, the TG500: the power switch, MIDI activity and Edit LEDs, headphone socket, volume knob, two line by 24-character display, 12 miscellaneous buttons and a selection of waveform and data card slots are all in just the same locations too. The various buttons (for kit selection and editing) carry different legends, but the initial feel of the unit is very similar.

Moving to the rear panel, the resemblance to the TG500 disappears completely — there's a main stereo output as well as six individual outputs, and, crucially, the additional array of six trigger inputs. It is possible to use audio signals off tape or any drum trigger to fire the sounds contained within the RM50.

Internally, the RM50's sounds are based around a selection of Yamaha's second generation Advanced Wave Memory (AWM2) 16-bit samples. There are 133 in all, with the manual quoting a maximum sampling rate of 48kHz — I presume this has been reserved for cymbals and other sounds which have important high frequency content. The sample waveforms include masses of traditional kit sounds, some of which feature ambience and effects, as well as analogue drum machine sounds, latin percussion sound effects and synth waveforms — the latter samples are particularly effective when used either for bass parts or for adding something unusual to percussion sounds.

Polyphony is a maximum of 16 notes, and the unit is 16-part multitimbral — you wouldn't expect to find this on a conventional drum machine, and it's very useful. The available waveform memory can be increased through the addition of the optional SYEMB06 512 kbyte expansion board — the same as that available for the TG500. This allows you to load, via MIDI Sample Dump Standard or waveform cards, additional samples for use in RM50 voices. Waveform cards can be accessed through the three slots in the front panel, but are not stored in the machine. Cards for the SY77, TG55 and RY50 are all compatible with the RM50.

Being a child of the '90s, the RM50 has MIDI written all over it: MIDI controllers can be used to alter various parameters in real time, and sounds respond to pitch bend. This is great news, since this facility has been lacking in many Yamaha drum machines and synths that feature drum sounds. Leaving this option off the RM50 would have been a major let-down in what is otherwise a comprehensively specified product. Other MIDI refinements include a MIDI monitor — pressing the Shift and Play button enables this function. This isn't fully comprehensive, but simply shows note numbers, their velocities, and the MIDI channel(s) the notes appear on.

RM50 VOICES

The next step up in the programming hierarchy from raw waveforms is the Element; up to two Elements make up a Voice. Each element consists of a waveform with a wide range of sound sculpting parameters assigned to it — some of which are very unexpected. Each element can be assigned a level pan position and a pitch value of +/- three octaves (in one cent intervals). There is an attack, decay and release (ADR) envelope generator, which also features a Punch parameter; this sets the amount of time for which the element's attack level is held when a note is sounded. Next in line is the element's filter. This can be set to high pass (12kHz or 24kHz) or low pass (12kHz or 24kHz), or switched off entirely. A cutoff frequency of between 0 and 22.4kHz can be programmed, as well as a useful resonance setting.

Each element has an LFO setting with a choice of waveforms, including triangle, square, and sample and hold. A Pitch envelope is also available, as found on most Yamaha synths, which can be used to create portamento-type effects, although that is understating the effect somewhat. Most interesting is the element Delay parameter: this is a simple, but very useful, effect. It is not a true digital delay, but a novel piece of software that appears to work on MIDI data only — and, thankfully, with no compromise in polyphony. Each delay can have up to seven repetitions, and a delay time of up to 1,280 milliseconds (in 10ms steps) can be assigned. There is also a level and pitch offset (+/-12 semitones), so that each repeat can grow louder or quieter and/or rise or descend in pitch (fans of the Lexicon PCM70 will like this!).

A total of 1,128 Voices are provided on the RM50 — that's six banks each of 500 preset Voices, a further 500 Voice variations (which can be slightly edited by the user), and 128 user Voices that are completely user-editable. The highest level is the rhythm Kit, and there are 64 preset and 64 user kits on board with, again, the option to store more on plug-in cards. Simply put, a kit can contain one voice per MIDI note, although this isn't the full story — MIDI notes B0-A#2 can have two Voices assigned to them; the remainder (B2-B4) can only be assigned one Voice. This is where the polyphonic compromises arise: a MIDI note that fires two Voices, each with two Elements, will eat up four notes of polyphony.

In addition to ordinary kits, the RM50 offers a Pitched Voice alternative, where any Voice can be assigned to the whole MIDI note range (C2-C8). Pitched Voices can then be played much like a sound on a synth — in fact, the handful of synth waveforms on board the RM50 can be treated in just this way. As a taster, Yamaha have provided a number of bass sounds and pitched effects, as well as tuned percussion. A Pitched Voice can't be named, however; the name section of the display shows the name of the source Voice you have chosen for transforming into a Pitched Voice — slightly irritating, but not a major problem. There are also no specific memory locations for storing Pitched Voices, but each of the 16 MIDI channels can have its own alternative Pitched Voice, so you could say that there are 16 memory locations for Pitched Voices.

EDITING

The editing process has two levels, both accessed through the Edit button, not surprisingly. Press the button once and you are in Setup Edit mode; it is here that you build drum kits. There are only a few parameters here, used to assign voices and trigger inputs, adjust various voice levels against each other, define pitch bend parameters and select which MIDI controllers affect which parameters. A kit can also be named here.

Press Edit a second time, and you are in Voice Edit mode. The first two pages of Voice Edit contain a selection of so-called Easy Edit parameters which affect both elements in a two-element voice. Here you can quickly alter volume, pitch, decay, cutoff frequency, and element balance. Further pages offer more precise editing possibilities.

Note that there is a limit on what you can edit: Preset Voices cannot be edited; Internal Voices can only be given limited user variations (they are otherwise duplicates of the Preset Voices); and only the 128 User Definable Voices can be completely edited from scratch — you can, however, copy any voices into the user bank and edit them.

Utility options include trigger input sensitivity, a metronome click (which can be clocked to MIDI), program change table and MIDI bulk dump options.

With menu-driven hardware such as the RM50 — and most contemporary MIDI gear is the same — it is often necessary to press many buttons to get to a parameter or function that needs to be changed. Five or six button presses is not unusual and over 20 is not unheard of. Once you've got into the swing of using your new drum module, you may discover that there is one particular function that you alter regularly, and those 20-odd button pushes are getting you down. Well, fear not for Yamaha have already come to your rescue: a dedicated Macro button allows up to 10 sets of (up to 50) button presses to be recorded and replayed with only two — simply hit Macro and one of the other keys that is assigned to the macro you require. Macros can be named and the steps within a macro can be viewed at any time, although not edited. You'll also have to re-record each button press if you make a mistake when entering them.

Another welcome timesaver is the Chase facility, which allows individual notes to be selected from an external source — typically a MIDI keyboard, but potentially anything capable of transmitting MIDI note numbers; I was using the pads on a drum machine. Given that there are potentially a lot of voices within an RM50 kit, some way of quickly selecting a note to edit is very welcome — it's quite a drag editing kits and voices from the display.

IN ACTION

The RM50 is a fine machine and sounds great, but operationally it's a little tricky. Intuition doesn't help much in the early stages. One display prompt you'll see a lot of during your learning time is 'Can't edit this data!'. This appears whenever you try to do something to a preset Voice, and you soon learn how to avoid it. Should you want to slightly change a preset Kit that is made up of preset Voices, the only way is to copy it to an internal Kit, and copy the sound(s) you want to change from the preset banks to one of the 128 locations in the user bank — the voice is now editable. It is not possible to edit a factory voice and then store it in a user location, which would seem to be the most logical approach.

Thankfully, the manual does a good job of guiding you through a tricky machine. New users are advised to start at the beginning, read every word and follow every example. This way you obtain a great insight into your new instrument, fast.

On a positive note, edited sounds and kits don't have to be saved manually — once you've made an edit of any kind, it stays in memory until you initialise the unit or make a change of your own. This is very friendly.

OPINION

As with the latest Yamaha synths (SY77, SY99, SY85 et al), the RM50's AWM2 sounds offer a wide frequency range with a really thumping bottom end. There are some really excellent bass drums in here, and the rest of the sounds are equally dynamic. Cymbals sparkle and fade into silence instead of digital 'mush' — indeed, the RM50 is a noise-free unit. There is no on-board signal processor, but plenty of the sounds have been sampled complete with various amounts of room ambience or reverb. If this isn't enough, then you can use the separate outputs to add your own effects. When creating voices from scratch the filter is rather effective, and is a model of deceptive simplicity — use non-percussive waveforms and you'd think you were programming a synth, especially given the envelope generator and delay.

Amongst my favourite kits are 'Brazil', which features a wonderfully deep, rich, resonant kick drum plus a goodly assortment of Latin sounds, and 'MouthKit', which is pretty much self-descriptive. Rhythm patterns created with a traditional kit take on a completely new character when played with either of these two kits. There are plenty of suitable kit selections amongst the presets, whether you are into techno, house, fusion, or pop music — sounds that are identifiable with all these genres and more are already present, with no programming work necessary. Creating your own kits, with your own voices, does eventually become quite a simple task, and is ultimately highly rewarding.

Several kits are actually collections of similar sounds — kicks, snares, cymbals and so on. This is especially useful, since each type of sound can be assigned its own MIDI channel (and its own output if you wish) for instant access to a huge number of sounds. Could prove invaluable during recording sessions.

Apart from the rather unusual operating system — which might prove overpowering to a technically inexperienced drummer and does seem a bit stifling at times — the RM50 is a trouper. I tried to make it crash, but it held its ground — throwing far too much MIDI data at 240bpm does make it choke somewhat, but it never gives up trying to play all the notes. One slight idiosyncrasy shared by the majority of rhythm sound sources is the way in which rolls don't sound quite realistic — the machine gun effect, as it's known. There are ways of lessening the problem (for example, two elements within a Voice can be set to fire on alternate strikes), but it is always evident. While cymbals don't get cut off in a roll, the attacks never quite sound natural.

The bottom line is the sound, and here the RM50 scores highly. The price is also pretty attractive — £599 for all these great sounds, and half a dozen trigger inputs thrown into the bargain. Sequencer users in MIDI studios, recording engineers in need of further percussive muscle, and drummer's moving in or into electronic circles will all find something to covet in Yamaha's new module.

Further information

RM50 £599 including VAT.

Yamaha-Kemble Music UK, (Contact Details).