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Marcus Ryle: Designing The Alesis Quadrasynth

Marcus Ryle

Article from Sound On Sound, June 1993

From their early roots in affordable effects, Alesis have progressed so far that they now threaten to equip your entire studio — and even provide your keyboard. For their newest project, the Quadrasynth, Alesis have once more enlisted the expertise of Marcus Ryle, a designer with an impeccable background, including work on the great Oberheim synths. Paul White talks to him about his newest synth design.

Marcus Ryle was instrumental in the development of Oberheim's classic analogue synthesizers and has gone on to form his own company, Fast Forward Designs, which designs hardware and software for some of the top names in the hi-tech music business. Fast Forward Designs had more than a passing involvement in the development of the Alesis ADAT, they put in most of the hardware and software design for the BRC, and now they're working with Alesis on their new Quadrasynth. I put it to Marcus that since the introduction of LA synthesis, nearly every manufacturer has jumped on the same bandwagon, resulting in an unhealthy level of stagnation in sound generating technology, and that with few exceptions, manufacturers were as far as ever from giving us a truly acceptable user interface for sound editing.

Marcus Ryle: "That's a fair point, and in terms of true creativity and expressiveness, there does seem to be something lacking these days. The good old analogue synths were expressive instruments, but obviously they had a finite tonal palette. I think the popularity of sample-based synthesis is simply due to the fact that the available palette can be increased so widely. For example, in the Quadrasynth that we're working on now, you can have analogue synth samples, wavetables, digital sounds and a whole load of acoustic instruments which makes that technology a natural choice for sound generation."

Perhaps it's not the generation system that's at fault but the ways in which we can treat and process those sounds. For example, ring modulation, which worked so dramatically on the early analogue monosynths, has all but disappeared.

"That's very true; there are some machines that try to go in that direction, but it comes at a price. With the Quadrasynth, we wanted to take the most important elements to begin with — very high quality samples and 16MB of sound ROM. We felt a sweepable filter was a necessity and developed a digital design, though it isn't a resonant type. That choice was down to cost, because we wanted to maximise the number of voices, and with a polyphony of 64 voices, each voice with its own envelopes, LFOs and filter parameters, you can be a little bit more creative with layering and cross-fading sounds. We have also incorporated a very complete modulation system to handle virtually all the things that are modulatable."

That sounds very much like a reflection of your Oberheim days — specifically Matrix Modulation.

"Yes, though the credit for that really belongs to my Partner Michel Doidic, who developed it originally at Oberheim and carried the concept into the Quadrasynth. He was always a big fan of the early EMS stuff which had a matrix pin panel that allowed you to connect anything to anything. When we developed the Oberheim Matrix 12, we felt much the same as you feel now, in that new analogue synths of the time were being provided with fewer facilities.

"I feel that the Quadrasynth will be the most versatile machine in terms of effects programming, and I think that's very important, as effects are an integral part of creating new sounds. The environment in which a sound exists is now as important as the sound itself."

Before we leave the subject of voicing, what have you included in the way of non-sample style waveforms?

"We've got a number of analogue waveforms sampled from various synths such as MiniMoogs and Oberheims. We also have quite a large number of PPG and Microwave-type digital waveforms and some FM-style stuff. Since you can stack four sounds in each voice, you could do these vector type of things, or whatever you want to call it, where you could have different waveforms crossfade with each other and so forth. Many of the sounds are looped, even the sounds that wouldn't normally be used looped. For example, there's a sample of just the percussion of a Hammond B3 organ. In an organ it would simply die away, but because we've looped it, you can impose your own envelope on it and decide what you want it to do. We prefer to loop sounds wherever possible to give the user the maximum amount of flexibility."


Referring back to the modulation systems, will this allow you, for example, to modulate one sample loop with another?

"No, it's really all from control sources as opposed to audio sources. There isn't any ring modulation or true audio FM type of modulation. But then you have to provide a system that's usable. I feel that usability is an aspect of synthesis that is often overlooked, and I feel quite proud of what we've done. The difficult thing is that companies have to deal with the realities of the commercial market — if only a small percentage of the people are screaming for really useful editing features, then a difficult decision has to be made on how many features to provide and at what price. The DX7 was probably the one instrument that delivered the strongest strike against a really comprehensive user interface. They sold a ton of those machines, and it was a breakthrough product in many ways, but the message it gave to the marketing people was that you don't need a good editing interface to sell loads of synthesizers. Despite that, we still feel it's important, and for the Quadrasynth, we developed a custom LCD display, the sole purpose of which was to make manoeuvring easy while editing. It's easy to put in a big dot matrix display because that leaves the design of the user interface open until later, but that often leads to convoluted parameter access systems. Our aim was to make the interface as consistent as possible over its whole area of operation. That way, after a few minutes experience, you can find your way around the machine. Whatever edit mode you're in, every single function that you have available shows up in the display at that time. All the words appear in the display but just one of them is underlined — that's the one you have selected. You never have to guess how many functions might exist in any edit mode because you can see them all.

"In the Oberheim Matrix-12, we had six knobs which were active at the same time; in the Quadrasynth we have four knobs which give access to four parameters simultaneously, and if there are more than four parameters, then there'll be a series of pages. The display will always tell you which page you're on and how many pages there are. In addition to that, we provided two different modes of editing because of the way up to four voices might be stacked to produce a sound. You can think of it as being horizontal or vertical. You might want to edit one sound at a time and look at the attack, decay, sustain and release of an envelope, or you may want to edit all four sounds where now you might want to see the envelope release for all four voices simultaneously."

Do you have an equivalent of an easy edit function for people who want to make quick adjustments to, say, the overall attack or release times of a patch?

"What there will be is a kind of a combination of the two edit modes where you can see all four parameters at a time, but edit all four voices together rather than one at a time. I don't know if I'd call it an easy edit, though, because the whole thing has been designed for easy editing. The fact that the system isn't so multi-layered in operation means that you can get where you want very quickly.

"The display also shows MIDI channels 1 to 16 with a little block above each channel number that acts as a MIDI receive light. That enables you to monitor the MIDI activity on all 16 channels at the same time, and if you select one of those MIDI channels, you get access to the program that's assigned to that channel.

"There's a number of choices for parameter editing; there's the four pots, there's value up and down buttons, and there's a button underneath each pot to select the parameter without moving the pot — when you move the pot you automatically select it. And in the display, there's four bargraphs which show the levels of the four parameters. And if that isn't enough, the display also provides a numerical value for each parameter being edited.

"We wanted to be able to virtually write the user manual before we started the software, because once you know what you want the machine to do, you can design something that makes sense in terms of the way you operate it."

Is the software developed or are there areas you're still working on?

"At this point there are some final things in terms of MIDI performance controls and stuff like that which we're working on, along with some miscellaneous things, but hopefully, by the time you print this, it will be all done. An example is pitch bend; it would sometimes be nice to hold down a sustain pedal, play a bunch of notes, and when you bend, have it only bend the note you're currently holding. Or you could have an LFO that only comes in on the notes if you hold them down for a long enough time — any notes that were released, even if they had very long release times, would not be affected. From a master keyboard standpoint, we've fixed it so you can put a different program on each of the 16 MIDI channels and each program can contain up to four sounds.

You can also decide whether MIDI is going out or coming in, what the note range is and whether the keyboard should be functioning on that as well. With 64 voices, that's pretty flexible, especially if you're working with a sequencer or have a complex system involving other keyboards.

"The keyboard itself has monophonic aftertouch and that can be routed in the same way as the other modulation sources, so it can be used to control pitch, LFO, filter opening or whatever. If you have a keyboard split, you could set it so the aftertouch affects, for example, the bass sound but not the piano sound or whatever. That's rather more flexible than a global aftertouch that relates to everything that's playing."


Is there anything new on the manufacturing side that makes the Quadrasynth technically different from its competitors?

"Well, from an electronic standpoint, there are three custom chips inside and they are relatively sophisticated. The good thing about being able to do such a high level of integration is that the actual circuit board looks relatively simple. Obviously a lot of work has to go into the chips, but for the end user, this means a more reliable product. The Oberheim OB8 used to have 150 trimmers which had to be adjusted at the factory and periodically recalibrated. We made a big step with the Oberheim Xpander with a bunch of auto-tune capabilities, and really there was only one trimmer to calibrate everything for the six voices. Here, with the system being entirely digital, there's relatively little circuitry inside the machine and there's no adjustment or calibration required. We're quite proud of the chips — one of them is dedicated purely to the effect processing and has over five seconds of delay memory."

One area which I feel tends to get neglected by some manufacturers is the tactile quality of mod wheels. Pitch wheels in particular can be a problem and I've seen some designs with such a wide dead spot in the centre that they're virtually unusable. On the other hand, some are so finely set up that they're forever sending out spurious pitch information, even if you don't touch them at all.

"Don't you just hate it when that happens! What we do is, essentially, auto-tune the pitch wheel on power up so it's always centred properly. We've also positioned the wheel for ease of use, which is important on a 76-note keyboard."

Have you any future projects lined up for Alesis?

"Yes — we're not done yet. Alesis are taking up a lot of our design time, with Digidesign coming second. Since we have a relationship with both companies, there's a natural alliance and we'll be involved in interface products which bridge the gap between Digidesign's products and the ADAT. It looks as though we're going to stay pretty busy for a while.


Sound Generation: 16-bit PCM 48kHz sample ROM with sweepable filter per voice
Synthesis: QSComposite synthesis™
Number of Voices: 64-voice polyphony, each with sweepable filter, 3 envelope generators, 3 LFOs, programmable effects send and QS Modulation Matrix ™ Dynamic voice allocation
Keyboard: 76 keys (velocity, release velocity, aftertouch)
Waveform Memory: 16MB of onboard sample ROM plus ROM curd slot
Program Memory: OS Program Mode (128 preset, 128 user); QS Mix Mode (128 preset, 128 user)
Effects: 4 independent stereo effects processing busses with multiple simultaneous effects on each bus
Audio Outputs: 4 assignable (2 stereo pairs); headphone output
Digital Interface: Fibre Optic output (ADAT Multichannel Optical Digital Interface ™


  • ADD-one drum sound generator
  • ADD-drive sampling & disk drive option
  • ADD-two 16-bit, 16-voice drum sound generator
  • ADS 16-bit, 16-voice stereo sampler module
  • ADS-K 16-bit, 16-voice stereo sampling keyboard

  • LM850 56-channel programmable MIDI lighting controller
  • LD360M 6-channel MIDI-controlled lighting dimmer box

  • MMT8 8-track MIDI sequencer
  • HR16/HR16B 16-bit digital drum machines
  • SR16 16-bit digital drum machine
  • MIDIverb III, Quadraverb and Quadraverb GT digital effects
  • DataDisk MIDI storage device
  • ADAT 8-track 16-bit digital audio tape recorder
  • BRC remote controller and RMB meter bridge for ADAT
  • AI1 ADAT digital interface with sample rate converter
  • Quadrasynth S4 64-voice, 16-bit synth module
  • Quadrasynth S5: S4 with 76-note keyboard

  • SampleCell I, II and PC 16-bit sample player cards for Apple Mac and PC
  • ADAT I/O 8-channel digital interface between ADAT and Session 8 and Pro Tools

  • ACI ADAT computer interface

Prior to founding Fast Forward Designs, Marcus Ryle and partner Michel Doidic worked at Oberheim Electronics, where they headed the development of the Oberheim DSX, OB8, Xpander and Matrix 12.

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Publisher: Sound On Sound - SOS Publications Ltd.
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Sound On Sound - Jun 1993

Feature by Paul White

Previous article in this issue:

> Microdeal Replay 16

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> Atari Notes

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