The Quasimidi Sirius represents a comprehensive evolution in dance music production technology, positioning itself as a complete dance workstation that significantly expands beyond its predecessor, the Rave-O-Lution 309. Unlike the 309's single monophonic bass/lead synth, the Sirius incorporates three full polyphonic synthesizers unrestricted to specific roles, alongside a sophisticated 7-track sequencer, built-in arpeggiator, and dual effects processors. This German-engineered instrument achieves 28-note maximum polyphony across 7-part multitimbral operation, creating a self-contained studio for electronic dance music production.
The instrument's most distinctive feature is its integrated 11-band vocoder system, complete with a supplied gooseneck microphone, enabling the classic "robot voice" effects popularized by artists like Daft Punk and Air. Additionally, the Sirius incorporates an innovative beat-recognition system designed to detect external audio tempo and synchronize the internal sequencer accordingly, making it particularly valuable for DJ applications and live performance scenarios where synchronization with CDs or other audio sources is required.
Design and Interface
The Sirius adopts a retro-inspired aesthetic reminiscent of 1970s synthesizer design, featuring a predominantly dark brown and orange color scheme that evokes vintage analogue equipment. The physical dimensions mirror those of classic instruments like Korg's Mono/Poly, with a substantial deep front panel, black end-cheeks, and a compact 49-note keyboard providing velocity sensitivity but notably lacking aftertouch capability.
The control interface emphasizes hands-on operation with 24 dedicated knobs, 70 oval blue buttons featuring red backlighting, pitch-bend and modulation wheels, and an alpha dial for parameter adjustment. The front panel layout, while initially complex, minimizes dual-function controls, providing dedicated access to most frequently used parameters. A small backlit LCD display serves the menu system for deeper parameter access beyond the immediate knob controls.
The rear panel maintains standard connectivity expectations with MIDI In, Out, and Thru ports, stereo audio outputs, footswitch socket, and two specialized inputs dedicated to the vocoder and beat-recognition systems.
Synthesis Engine
The Sirius employs what Quasimidi terms "DTE Synthesis" (Difficult To Explain), a hybrid approach combining traditional subtractive synthesis methods with sample-based elements. Each of the three polyphonic synthesizer voices features two oscillators per voice, though these cannot be edited independently, limiting advanced techniques like oscillator sync and cross-modulation while still providing genuine detuning effects.
The synthesis architecture offers 125 oscillator "Macros" - pre-configured combinations of waveforms including traditional analogue staples (sine, pulse, sawtooth, triangle) alongside specialized waveforms like TB-303 emulations, synth-choir, synth-string, and bass timbres. The signal path follows classic analogue synthesizer design:
Oscillator Section: Features octave settings calibrated in organ-style feet measurements, comprehensive detuning up to 24 semitones (one-cent precision for the first semitone), glide/portamento control, and monophonic/polyphonic switching for authentic monosynth emulation.
Filter Section: Provides three filter types - 24dB and 12dB low-pass filters plus 12dB high-pass filtering, all with resonance extending to self-oscillation. The drive parameter adds harmonic saturation particularly effective for acid basslines and aggressive lead sounds. Keyboard tracking adjusts filter brightness according to keyboard position, while velocity sensitivity and comprehensive envelope modulation complete the filter's capabilities.
Modulation Systems: Each voice includes a pitch envelope generator with attack/decay parameters and bidirectional modulation amounts. The LFO section offers six waveform choices, rate control with MIDI clock synchronization options, and routing to oscillator, filter, and amplifier sections simultaneously.
Envelope Generators: Both filter and amplifier sections feature full ADSR envelope generators, complemented by 128 preset "Macro" envelopes accessible via front-panel knobs for rapid sound design without menu diving.
Drum Machine Capabilities
The drum section represents a significant portion of the Sirius's sound generation, organized into four dedicated parts: Bass Drum, Snare, Hi-Hat, and Percussion. The Percussion section uniquely accommodates 12 simultaneous voices while occupying only a single MIDI channel. Each drum part provides access to basic waveforms plus 96 preset sounds and 96 user memory locations.
Drum sound editing capabilities match those of the synthesizer voices, enabling extensive sound manipulation that can transform percussion elements far beyond traditional drum timbres. However, a notable limitation exists in the Percussion Set editing: modifications automatically overwrite original preset data, potentially affecting other voices and sequencer patterns utilizing those sets.
The drum programming interface adopts the familiar TR-909 grid approach, utilizing the 16 numbered buttons as a step sequencer grid corresponding to 16th-note divisions within a 4/4 bar. Multiple resolution options accommodate 8th notes, 8th-note triplets, 16th-note triplets, and 32nd-note programming precision.
Sequencer and Pattern Management
The 7-track sequencer operates exclusively in 4/4 time signature with a tempo range spanning 51-250 BPM, offering both real-time and step-time recording methods. The pattern-based architecture supports Patterns containing up to seven "Motifs" (track sequences) of varying lengths from 1-8 bars, with automatic looping to accommodate different motif lengths within a single pattern.
Pattern organization allows for comprehensive Song construction with up to 100 Pattern steps per Song, though individual steps can repeat without counting against this limit. The overall Song length restriction of 600 bars provides substantial composition scope, with storage for 16 complete Songs.
Real-time recording captures performance data with subsequent quantization and groove adjustment capabilities. Step-time programming utilizes a display-based event list defaulting to 16th-note resolution, though other timing divisions are available. A significant limitation exists in step-time mode's inability to handle chord input and the lack of comprehensive edit facilities for correcting real-time recording errors.
The sequencer incorporates 142 preset Patterns with the ability to extract individual Motifs for new compositions. A randomize function can automatically populate new Patterns with Motifs selected from preset Pattern libraries, offering creative starting points for composition.
The integrated Mixer section provides intuitive real-time control during Pattern recording, with dedicated knobs for each track controlling level, pan, and effects sends. These knob movements can be recorded into Patterns, and individual track muting is available both from mixer buttons and keyboard shortcuts.
Arpeggiator and Performance Features
The built-in arpeggiator offers seven monophonic preset types (Up, Down, Up/Down, Random, Assign, Reverse Assign, and Assign/Reverse Assign) plus nine user-programmable patterns supporting up to 32 steps and chord incorporation. The Assign modes create arpeggios based on the order of note input, providing more musical and less predictable results than standard algorithmic types.
Performance enhancements include Chord Trigger functionality, which repeats held chords in rhythm with selected sequencer parts, and the Gater function, which creates rhythmic gating effects by controlling sustain timing. A Hold feature maintains arpeggios without continuous key depression, while sustain pedal transpose capability allows real-time arpeggio transposition across a two-octave range.
Live performance capabilities extend through several dedicated features:
- Favorite Patterns: Eight user patterns can be stored on numbered keys 1-8 for instant access per Song
- Breaks: Four Break patterns (keys 9-12) can replace currently playing patterns for predetermined durations up to eight bars
- Loop Tracks: Individual Motifs can be assigned to keys 13-16 with custom sound assignments
- Keyboard Shortcuts: White keys C-E provide track muting, while the second keyboard octave enables real-time transposition of synth parts
Vocoder System
The 11-band vocoder represents one of the Sirius's most distinctive features, incorporating a 9-band filter bank plus dedicated high-pass and low-pass filters. The system accommodates multiple signal routing scenarios: external microphone input as modulator, line-level audio as either carrier or modulator, and internal sound interaction where any combination of the seven sequencer parts can serve as modulator, carrier, or both simultaneously.
Sixteen editable vocoder programs provide starting points for various effects, from classic "robot voice" timbres to more experimental cross-modulation effects. The editing system allows adjustment of individual filter band levels and pan positions, high-pass and low-pass filter settings, and global effects send amounts. Modifications save with individual Songs while preserving original program templates.
The vocoder's user interface emphasizes real-time control through the seven Mixer knobs, which provide hands-on adjustment of filter bands 2-9, eliminating theoretical complexity in favor of intuitive sound shaping. When not used for vocoding, the microphone remains active and mixes with the main stereo output, supporting DJ and live vocal applications.
Beat Recognition Technology
The beat recognition system represents an ambitious attempt to synchronize the Sirius with external rhythmic audio sources such as turntables or CD players. The system requires rhythmic input with clearly defined bass drum pulses fed through either vocoder input, followed by a bar of tempo tapping using the dedicated Tap Tempo button, after which three bars are needed for tempo stabilization.
Practical implementation proves somewhat challenging, requiring precise tempo tapping and optimal input material for reliable synchronization. The system performs better with processed CD audio than simple drum machine pulses and struggles with tempo changes. The Tap Tempo button's placement behind prominent knobs and near the headphone socket complicates accurate operation. While functional with practice and patience, the beat recognition system requires realistic expectations regarding its reliability and ease of use.
Effects Processing
Two independent effects processors handle the Sirius's signal processing requirements, though the implementation remains basic compared to dedicated effects units. The first processor provides reverb algorithms (Room, Metallic, Chamber, Hall, Cathedral, Plate) plus delay options (Delay, Pan Delay), while the second handles modulation effects (multiple Chorus variations, Flanger, Short Delay, Pan Delay).
Effects operation is global, meaning all sounds and patterns receive the same processing, though individual track send levels allow variation in effect intensity. Effects settings save with individual Songs, maintaining consistent sonic character across compositions. The system notably lacks the parametric EQ found in the Rave-O-Lution 309, though the "Overblast" bass boost function carries over.
Sound Character and Applications
The Sirius targets electronic dance music production specifically, with preset sounds and patterns optimized for genres including techno, trance, jungle, and Euro-dance styles. The characteristic sound palette emphasizes analogue-style aggression and edge, though smoother pad sounds provide textural variety. Drum and percussion timbres lean toward dirty, electronic, and analogue-inspired timbres alongside more natural acoustic drum voices.
Factory presets demonstrate strong dance music relevance, though some groups exhibit tonal similarity that may require user programming for broader sonic variety. The preset Pattern library includes recognizable dance music elements, sometimes approaching commercial hit simulations, which could limit originality if used extensively without modification.
The random sound generation feature provides creative starting points with automatically generated names like "Nasdobin," "Gatfokis," and "Daxwomix," offering both sonic and nomenclatural inspiration for sound design exploration.
