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Quasimidi Sirius

Dance Workstation By Derek Johnson & Debbie Poyser
Published October 1998

Quasimidi Sirius

There's a new star in the current galaxy of groovy dance‑oriented synths, but does it outshine the rest? DEREK JOHNSON and DEBBIE POYSER investigate Quasimidi's most comprehensive dance music creation tool yet.

Among the hotter products produced by both Quasimidi and Roland in recent years have been silver all‑in‑one dance machines incorporating drum machines, sequencers and synth engines. Neither Quasimidi's Rave‑O‑Lution 309 nor Roland's MC505 (reviewed in the May '97 and April '98 issues of SOS respectively) featured a proper keyboard, but both manufacturers have obviously decided that there is room in the market for similar devices which do — hence we now have Roland's JX305, reviewed on page 204 of this issue, and Quasimidi's Sirius.

The Sirius, however, is a fair bit more than a 309 with a keyboard. For a start, the 309 had just one monophonic bass/lead synth, while the Sirius has three polyphonic synths which aren't just restricted to bass or lead duties. The new instrument pretty obviously aims to be a total dance workstation, incorporating those three synths, a 7‑track sequencer, an arpeggiator, and two effects processors. Maximum polyphony is 28 notes, and the Sirius is 7‑part multitimbral. The gooseneck mic sticking up from the front panel is not just for decoration: the Sirius also features an 11‑band vocoder and, to further reinforce the dance‑machine image, has a built‑in 'beat‑recognition' system designed to detect the tempo of rhythmic audio input and regulate the Sirius' sequencer to match. If it works, this could be useful in the studio as well as on stage, since while the Sirius' sequencer is being sync'ed to a CD it can itself provide master MIDI clock for any connected MIDI sequencers and drum machines — making it possible for a whole studio to be sync'ed to a CD.

Retro Styling

The rear panel showing connections to the vocoder/beat‑recognition system (on the left).The rear panel showing connections to the vocoder/beat‑recognition system (on the left).

The Sirius is about the size of Korg's old Mono/Poly analogue synth, and has a similar look, with a deep front panel, black end‑cheeks and a short (49‑note) keyboard featuring velocity but not aftertouch sensitivity — the synth doesn't even respond to aftertouch from an external MIDI device. The colour scheme is predominantly dark brown and orange, which certainly has a vintage '70s feel. There's a fairly high knobbage quotient (24 knobs), and 70 oval blue buttons with red backlighting (the same as on the 309), a pitch‑bend wheel, mod wheel and alpha dial complete the controller lineup. The front panel is busy, and confusing at first sight, though thankfully there are few dual‑function controls. However, a dedicated control is not provided for every parameter — while the knobs provide a moderate degree of editing power, there's a menu system, using the small backlit display, which gives access to all the synth's parameters.

At the back are the usual MIDI In, Out and Thru, a pair of audio outputs, a footswitch socket, and two inputs for the vocoder or beat‑recognition system.

The Synth Inside

Quasimidi Sirius

The synth controls, at the top left of the panel, access a synthesis engine similar in feel to that of the Rave‑O‑Lution, and of quite sufficient complexity for most people. The Sirius' 7‑part multitimbrality includes three polyphonic synth and four drum parts. Each synth voice, according to the manual, has two 'oscillators', though when you edit a voice there appears to be no way to access a second oscillator. The only evidence that there are two comes when detuning them: the effect is genuinely that of one oscillator being detuned against the other, but the fact that they can't be edited separately precludes such dual‑oscillator tricks as oscillator sync and cross‑modulation.

125 oscillator 'Macros' (combinations of two waveforms, some identical and some different) are available, which make use of a selection of traditional analogue‑style stalwarts such as sine, pulse, sawtooth and triangle, plus some TB303, synth‑choir, synth‑string and bass waveforms. After an oscillator Macro has been chosen, it can pass through a traditional digital emulation of an analogue synth, as follows:

  • Octave setting: this is something like the facility found on certain analogue synths and allows you to set a sound's octave range. Quasimidi calibrate it in feet, like drawbars on an organ.
  • Detune: up to 24 semitones of detuning is possible, in one‑cent steps for the first semitone, then in semitones thereafter.
  • Glide: sets portamento time.
  • Monophon on/off: sets whether the sound will play monophonically or polyphonically, so you can emulate a monosynth if you like.
  • Pitch EG (Envelope Generator): a very basic envelope with attack and decay and a positive or negative 'mod amount' which sets how much pitch modulation is applied to the sound.
  • VCF (Voltage Controlled Filter) parameters: Drive (overloads the filter stage; recommended for "acid basslines and aggressive solo sounds". In practice it seems to give sounds more edge and body); VCF Type (low‑pass 24dB or 12dB, and high‑pass 12dB); VCF Cutoff and Resonance; Keyboard Tracking (controls filter cutoff frequency according to where you play on the keyboard — the higher up the keyboard, the brighter the sound); VCF Dynamic (determines how the filter responds to keyboard velocity); VCF Envelope Modulation (sets by how much the EG affects the filter); VCF EG (offering two ways of setting a filter envelope: define attack, decay, sustain and release via the parameter access system, or choose one of 128 preset filter envelope types with the front‑panel VCF EG Macro knob).
  • VCA (Voltage Controlled Amplifier) parameters: Level; VCA Dynamic (controls a sound's volume with keyboard velocity — essentially a switch for turning velocity sensitivity on or off for a sound); VCA EG (sets amplitude envelope: as with the VCF EG, use the display, or choose from 128 preset types with the VCA EG Macro knob).
  • LFO (Low Frequency Oscillator) parameters: LFO Waveform (six choices); LFO Rate (choose a value or sync the LFO to MIDI clock); LFO Depth; LFO Amount (defines how much LFO modulation is applied to the oscillator, VCF and/or VCA).

As you can see, there's more than enough sound‑mangling power in the detailed editing levels of the Sirius. However, if you don't want to get your hands quite that dirty, quick and easy editing is available from the front panel. The 13 knobs dedicated to the synth section are divided into four areas:

  • Modulator (or LFO), where LFO Depth and Rate can be adjusted, and an LFO 'Macro' — a preset LFO routing — selected.
  • Oscillator, where a sound's basic waveform can be chosen, Glide (portamento) time and Detune amount can be set, Filter Overdrive applied, and a sound transposed by a maximum two octaves down or one octave up.
  • Resonance Filter (VCF), which provides quick access to the three filter types, cutoff frequency, resonance, keyboard tracking and VCF Dynamic. This section also offers a VCF EG Macro knob and one labelled Envelope Mod, which actually sets envelope depth.
  • Amplifier (VCA): this section has VCA EG Macro and VCA Level knobs, a VCA Dynamic switch, and a Release switch, which automatically lengthens an envelope by a fixed amount — so if you have a short sound selected, you can instantly give it a long decay.

A lot could be done to a sound using just these knobs, and naturally they can be used to vary a sound dynamically while it's playing. Their movements can also be recorded into the Sirius' sequencer, as well as transmitting over MIDI.

User‑programmed sounds can be named with up to eight characters (which wasn't an option with the 309) and saved in one of 96 synth user memory locations. The 288 presets show off the possibilities. Incidentally, the presets are arranged in a way that's very specific to Quasimidi: synth sounds are in three banks (A, B and C), and within each bank are six broad categories (Bass, Dirty Bass, Pad, Plucked, Solo, and Effect), with 16 sounds in each category. These categories each have a switch for easy selection, and you swap between banks with successive button presses. For a bass preset you'd press the Bass button, to access Bank A basses; press again for Bank B basses; one more time and you've arrived at the Bank C basses; four presses access the User bank. Once you're in the right category and Bank, sounds are selected using the 16 numbered keys above the keyboard.

The 96 synth user memories will probably fill up pretty quickly, at which point you'll want to save them externally. The Sirius will certainly oblige, allowing you to dump Sound, Song or All data via MIDI. One useful option is the Momentum Data Dump, which saves a snapshot of all the Sirius' currently‑set parameters to an external device, even if they haven't been stored yet.

Drum Major

Quasimidi's Rave‑O‑Lution 309 was arguably even more drum machine than it was synth, presenting one monophonic synth part alongside a comprehensive 4‑part drum section. The arrangement of the 309's drum section is largely carried over to the Sirius. The four parts are Bass drum, Snare, Hi‑Hat, and Percussion, although the last is a set of 12 percussion voices; these can all sound at the same time but only occupy a single MIDI channel. Each drum part has a collection of basic waveforms, plus 96 preset sounds and 96 user memories. Arguably this is overkill, especially on the user memory front. It would be quite possible to run out of synth sound memories while having some of the many drum sound memories unused, yet you can't save synth sounds in drum slots.

Each drum sound can be treated with virtually the same parameters as the synth waveforms, so drum sounds don't even have to sound like drum sounds when they're finished with. You've got to start with a drum waveform, obviously, but after that the sky's the limit. Bear in mind that a Percussion sound set behaves as one drum sound, so if you alter filter cutoff for the Percussion part, for example, this affects all 12 Percussion sounds in the set.

And speaking of Percussion, there's one small problem... A Percussion sound has as its source a Percussion Set (the assignment of 12 Percussion waveforms to 12 keys of the keyboard, plus level, pan, tuning and effects send parameters). There are 20 Percussion Sets on board, and though they're already filled with waveforms, they can all be edited. However, when you make an edit the Sirius automatically saves it to that Set, overwriting the original. So once you edit a Percussion Set, any Percussion voice using that Set will no longer sound correctly. This would also affect sequencer Patterns which use that voice.

Making Tracks

The Sirius' 7‑track sequencer has dedicated transport controls and also uses the numbered buttons above the keyboard. It's fixed in 4/4 time (so no prizes for guessing what kind of music Quasimidi think you'll be producing with it), has a tempo range of 51‑250bpm, offers real‑ and step‑time recording, and is pattern‑based. Patterns have up to seven 'Motifs' (one on each track of the sequencer) which can be be 1‑8 bars long. If a bass drum Motif is only a bar long and a synth Motif plays for eight bars, the drum Motif automatically loops eight times. Patterns are chained to make Songs, with up to 100 Pattern steps in a Song, though steps can be repeated without affecting this limit. The overall restriction on Song length, however, is 600 bars, and the Sirius has memories for 16 Songs.

Real‑time programming operates as you'd expect: play and the sequencer records the data, after which you can comprehensively quantise and/or apply 'swing', courtesy of the Groove parameter. Programming in step time involves scrolling through an event list in the display, inputting the desired note on each step. While the event list defaults to 16th‑note resolution (that's 16 steps per 4/4 bar), a choice of 8th, 8th triplet, 16th‑note triplet or 32nd‑note resolution is available. You can't enter chords in step‑time mode, and velocity and gate‑time information are entered separately, using front‑panel buttons, despite the fact that the Sirius' keyboard is velocity sensitive.

Drum sequence programming is via the numbered 1‑16 buttons: these behave as a drum grid, as with the TR909 (and 309), with each button corresponding to a 16th note in a 4/4 bar (though you have the same resolution options as step‑time recording). To record a complete rhythm part you'd make several passes, laying down a different drum track each time.

When it comes to editing a Pattern, the Sirius has a couple of shortcomings: the first is that there's no proper edit mode. If a real‑time recording has a mistake in it, the best you can do is go into step‑record mode and change the offending event (and this possibility isn't even mentioned in the manual). There's no 'microscope' event‑edit mode such as you'd find on a Roland Microcomposer. An additional complication is that it's not possible to edit chords in step mode. So if you were recording in real time and played a chord wrong, you'd just have to play it again, and since there's no punch‑in facility you'd have to play the whole thing again.

As you'd expect, there are preset sequencer Patterns — 142 of them — and Motifs from within these can be used in new compositions. A randomise function is also available: the Sirius can pick a Motif from any of its preset Patterns for each part of a new Pattern. This is a bit of a cheat, but it could be interesting to use live, and if you like the result you can save it to a user Pattern. Should you actually want to use a preset Pattern in a Song, a quirk of the operating system means that you'll need to copy it to a user memory first.

The Mixer section is very handy when a Pattern is being recorded: each sequencer track has its own knob, for quick, intuitive adjustment of level, pan and effects sends — select which will be adjusted using the three buttons to the left of the Mixer. Movements of the Mixer knobs can be recorded into a Pattern, and tracks can be muted and unmuted using the buttons below the knobs. When Patterns are being chained into a Song, track mute settings can be different for each step, so the maximum sonic variety can be squeezed out of even a small number of Patterns.

One useful facility has failed to make it from the 309 to the Sirius: the Master Track. With the 309, front‑panel knob tweaks for an entire Song were recorded into a sequencer Master Track, so you could record a tweaking 'performance' for a whole Song. As the Sirius can record knob movements into Patterns, Quasimidi have left the Master Track off, which is a shame.

Finally, note that the sequencer can be the sync master or slave in a more complex MIDI setup, and that it responds to MIDI Song Position Pointers.

Ups & Downs

The arpeggiator offers seven preset monophonic arpeggio types: Up, Down, Up/Down, Random, Assign (arpeggiates the notes in the order you play them), Reverse Assign, and Assign/Reverse Assign. There are nine extra arpeggiator patterns that can be overwritten with your own. User patterns, which can incorporate chords, can be up to 32 steps long.

Additional sophistication is added with the Chord Trigger and Gater facilities. The Chord Trigger repeats whatever chord you've just played, in a rhythm triggered by a sequencer part of your choice; you could trigger the chord with the bass drum part of a sequencer Pattern, for example. The Gater function is similar, but cuts off the sustain of the sound, giving a rhythmic gated effect such as you can achieve conventionally by triggering the opening and closing of a noise gate with a rhythmic pulse.

Part of the fun of an old analogue synth is holding an arpeggio and transposing it in real time, and this is possible with the Sirius. The trick is to press and hold a connected sustain pedal: while an arpeggio is active this allows it to be transposed up or down over two octaves from the keyboard. Arpeggios can be recorded into the sequencer for instant track creation, and the arpeggiator can also be used at the same time as a sequence Pattern is playing, though this will have implications for polyphony. Finally, a Hold feature repeats the arpeggio without the need to keep your fingers on the keys.

Hit That Perfect Beat?

Quasimidi state that any audio you want to sync the Sirius to, using its beat recognition system, should be rhythmic, with an easily locatable bass drum pulse. External audio is fed into the Sirius via either of the two vocoder inputs, and you have to tap along in time for a bar, using the Tap Tempo button, after which it needs three bars to settle on a tempo. In practice, however, the system seemed a bit flaky: at one point it had trouble sync'ing to a simple bass drum pulse from a drum machine, and it certainly wasn't happy tracking tempo changes. With rhythmic material from a CD it fared rather better, but you have to be very exact with your tempo‑tapping: the more on‑the‑nail you are, the better the results. The task isn't made easier by the fact that the Tap Tempo button is small and in an awkward, position just behind two prominent knobs and to the left of the headphone socket, which makes it harder to hit squarely. You have to give it a good confident bashing, too, and even when we thought we were doing everything right the display sometimes showed tempos which were wildly out.

In short, you can make this facility work properly, but it needs practice and patience. It should be good enough for DJs segueing records with their own material, but if the beat recognition system is important to you, try to check it out before buying.

Vox Clever

One of the 309's optional expansions adds two audio inputs, so external sound sources can be treated by its synth engine. The Sirius doesn't have this facility — at least, not exactly. Instead, Quasimidi have provided a vocoder with a 9‑band filter bank, plus high‑pass and low‑pass filter, complete with a gooseneck microphone. Vocoders were discussed in the January 1994 issue of SOS (and if you want to know the theory, dig it out), but to recap briefly and simply, they enable the character of one signal (the modulator) to be imposed on another (the carrier). The more filters the vocoder has, the more accurately it can analyse the frequency content of the modulator signal — super‑duper vocoders of old had up to 22 filters.

The Sirius' vocoder can take input from the mic as the modulator signal, or line‑level audio as either carrier or modulator. In addition, two onboard sounds can interact with each other as modulator and carrier, or the same sound can be both modulator and carrier. In fact, it's possible to select up to all seven sequencer parts as modulator or carrier, or both at the same time. This effect is quite fascinating and would take you a long time to achieve with more conventional means, if you could at all.

Of course, the vocoder effect that everyone is familiar with is the 'Mr Blue Sky' effect, employed more recently and credibly by French popsters Daft Punk and Air. With some tweakage (find the right basic sound and set up the level of the mic carefully), you can replicate this effect. However, since you can do so many other fun things with this vocoder, why restrict yourself?

The vocoder is editable to a certain extent: Quasimidi provide 16 vocoder programs, badly explained in the manual: you can tweak the level and pan position of each of the filter bands, their low‑ and high‑pass filter levels, and a global effects send level for each program. Any edits can be saved with the current Song, but the programs themselves remain unchanged. One thing that contributes greatly to the vocoder's ease of use is the fact that the seven Mixer knobs, plus the Vocoder volume control, can tweak the levels of filter bands 2‑9, so you can mess with the sound in a totally non‑theoretical and hands‑on way.

One last thing to mention is that the mic can still be used when the vocoder is switched off: the mic's output is mixed with the Sirius' stereo output, and can even be treated with the effects — good for DJs and live performers in general.


The Sirius looks, feels and sounds the part. Its physical resemblance to an analogue monosynth can only stand it in good stead for the dance market, whose fondness for compact, easily portable sound machines has been demonstrated by Korg's Prophecy lead synth, Roland's MC303 and 505, and Quasimidi's own Rave‑O‑Lution 309. On the sound front, while the preset palette is not especially varied (with the exception of the drum sounds), it is very well targeted — and users prepared to program can introduce more sonic variation themselves. The provision of 128 filter and amplifier EG Macro presets is clever, making programming easier for the novice. Presets of this kind have been used on the odd synth before (Yamaha's SY85 has something similar), but probably never in these kind of numbers. The only real fly in the ointment when it comes to programming is the limited number of onboard synth sound memories compared to the number of drum sound slots.

In use, after you're familiar with the layout and multiplicity of buttons, the Sirius is intuitive, as is its sequencer. However, the latter is not a match in sophistication for the one available on (for example) the Roland JX305, and the fact that it's fixed in 4/4 time could also be seen as a limitation. The dedicated Mixer section, however, is worth its weight in gold knobs.

Especially commendable is the way in which, when you're doing one thing — editing a sound, say — you can still do another, such as tweak the level or pan position of the sequencer part the sound you're editing is assigned to. This makes the Sirius feel like a very hands‑on instrument. When you add in the large amount of dedicated knob control, trendy features such as the vocoder and arpeggiator, and nice little touches like the patch randomise function (surely destined to be popular) it's not hard to work out that Quasimidi are onto a winner. At £799, it should positively fly off the shelves, and could be the company's most successful product to date.

The Full Treatment: Sirius Effects

Effects are basic: one of the Sirius' processors offers reverbs (Room, Metallic, Chamber, Hall, Cathedral, Plate, Delay, Pan Delay), while the other provides modulation effects (Chorus, Slow Chorus, Fast Chorus, Super Chorus, Feedback Chorus, Flanger, Short Delay, Pan Delay). Pan Delay appears twice, for some reason... Note that effects are global: if a reverb and a chorus are set up, for example, all sounds and Patterns, and the current Song, will be processed with them, though send levels for each track in a Pattern allow you to vary effect amounts. Luckily, effects settings are saved with each Song.

The Rave‑O‑Lution had similar effects capabilities to the Sirius, but also offered a 2‑band parametric EQ. This is missing on the Sirius, though the 309's 'Overblast' bass‑boost is present.

Patch Test

The Sirius isn't what you'd call a general‑purpose synth — you certainly wouldn't buy one for orchestral music. It has a huge dance bias (all the preset Patterns and many of the preset sounds) and works fabulously well for that purpose, though you could conceivably use it for any style of synth/hi‑tech music.

While the factory presets are generally very good, there's occasionally a sameness about groups of presets. The characteristic Sirius 'sound' is analogue, aggressive and edgy, though there are some more subtle, smooth pads on board. Drum and percussion timbres are dirty, electronic and analogue in feel, with a collection of more natural drum voices available too. Some might say 96 each of bass drums, snares and hi‑hats is overdoing it a bit, though. On the whole, the sounds are perfectly optimised for their target market — think Prodigy, Sash, Kraftwerk, euro‑techno, jungle... The same goes for the preset Patterns, though it's hard to discuss favourites, since none of them are named. Some of the simulations of recent dance hits are rather too close for comfort, as you'll notice instantly if you hear them. And if you make too much use of preset patterns, you won't be setting many new trends, just following them.

The Randomise button on the front panel randomly generates a new sound (or drum kit), complete with randomly stupid name. Personal faves include: Nasdobin, Gatfokis, Daxwomix, Calroxii, Nafoonia and Zagbonio. If you were Terry Pratchett you could buy a Sirius just to generate new character names.

Brief Spec

  • Synthesis System: DTE Synthesis.
  • Polyphony: 28‑note.
  • Multitimbrality: 7‑part.
  • Preset Sounds: 672 ROM; 480 User (96 each for synth, bass drum, snare, hi‑hat and percussion).
  • Sequencer: 7‑track; 142 ROM Patterns, 100 User Patterns; 16 Songs.
  • Arpeggiator: 16 preset Programs, nine of which can be overwritten with user patterns; Chord Trigger and Gater features.
  • Effects: 2 effects processors; Overblast bass boost.
  • Keyboard: 4‑octave, velocity‑sensitive, with pitch‑bend and mod wheels.
  • Display: 2‑line x 16‑character, backlit.
  • Vocoder: 11‑band, with 16 editable presets and supplied gooseneck mic.
  • Beat‑recognition system.
  • Connections: MIDI In, Out & Thru; L/R stereo audio outs on quarter‑inch jacks; 2 input jacks for vocoder/beat recognition system; quarter‑inch footswitch jack; front‑panel mic and headphone sockets; external PSU socket.

Difficult To Explain

It's hard to tell what synthesis system the Sirius uses, because Quasimidi don't say, preferring not to "confront musicians with too much technology". What we can tell you is that it employs the traditional subtractive method, as found on analogue synths, and that there are definitely some samples in there. However, the white noise 'waveform' doesn't change in pitch across the keyboard, which would suggest that it's either produced by a real noise generator or modelled in some way. So what do Quasimidi call all this? DTE Synthesis, because it's "Difficult to Explain"!

Performing Arts

The Sirius has several features especially suited to performance use:

  • Favourite Patterns could be used to create new pieces on the fly, as you can store eight of the 100 user Patterns on the first eight of the numbered keys for each Song.
  • Breaks are similar to Favourite Patterns, though there are only four in a set, stored on keys 9‑12. A Break can be triggered while a sequencer Pattern is playing and it will replace the currently playing Pattern for a pre‑defined duration (up to eight bars).
  • Special Loop tracks are similar to Breaks, except that in this case single Motifs, from any of the user and the first 100 preset Patterns, can be assigned to keys 13‑16, along with your choice of sound. A Loop Track replaces one of the current Pattern's Motifs.
  • Mute Tracks lets you mute sequencer tracks from the keyboard (using white notes

C‑E), as an alternative to the Mixer section buttons — possibly more convenient live.

  • Transpose Tracks allows you to transpose the three synth parts using the second octave of the keyboard (C‑B), by up five or down six semitones.


  • Very hands‑on interface.
  • Sounds just right for target market.
  • Built‑in vocoder, with free gooseneck mic.
  • Logical patch organisation.
  • Arpeggiator.
  • Fun patch‑randomise feature.
  • Looks brilliant.
  • Reasonable price.


  • No Pattern naming.
  • Too many drum patches.
  • Basic effects.
  • Beat recognition system a bit flaky.
  • Keyboard doesn't transmit or respond to aftertouch.


Any shortcomings the Sirius has are relatively minor, and overall it's a very desirable little instrument, with the looks, sounds and features to make a real impact on the electronic/dance music market.