The GEM S2R is a professional 3U rackmount synthesizer module that represents an enhanced and expanded version of General Music's acclaimed S2 keyboard synthesizer. Launched in 1994, the S2R incorporates significant improvements over its keyboard predecessor while maintaining the same intuitive operating system and exceptional sound quality that made the original S2 series popular among professional musicians.

As a full-featured S+S (Sample + Synthesis) workstation in module format, the S2R combines PCM sample playback with advanced synthesis capabilities, offering musicians a comprehensive sound generation platform suitable for both studio and live performance applications. The unit's open-ended design philosophy allows for continuous expansion through software updates and sample loading capabilities.

Key Features & Enhancements

The S2R builds upon the S2's foundation with substantial improvements including increased polyphony (up to 32 notes), an expanded ROM sound library, and enhanced Sample Translator software built directly into ROM. The module features dual digital signal processors, comprehensive MIDI implementation, and an advanced sequencer capable of handling up to 250,000 events across 16 tracks.

Notable operational improvements include a sophisticated masking function for sound library management, the ability to distinguish between ROM and user-created sounds, enhanced editing capabilities, and support for Standard MIDI Files. The unit maintains full compatibility with S2 data while offering expanded functionality for sound creation and performance.

Sound Generation Architecture

The S2R employs advanced PCM synthesis utilizing wavetable technology with multiloop and crossfade multiwave capabilities. The 6MB ROM waveform memory is complemented by 2MB of sample RAM, allowing users to import samples in various formats including Sound Designer, Avalon, MMA Sample Dump Standard, and direct Akai S1000 disk formats. The synthesis engine features 32 oscillators with dynamic voice allocation and intelligent priority management.

Each voice incorporates dual programmable digital filters offering five filter types (Low Pass, High Pass, Band Pass, Parametric Boost, and Parametric Cut) with resonance control. The system supports dynamic stereo panning and maintains professional audio specifications with a signal-to-noise ratio exceeding 96dB and frequency response from 10Hz to 18KHz at a 41.7kHz sampling rate.

Operating Modes & Performance Features

The S2R operates in four primary modes: Single, Layer, Split, and Multi. Multi mode provides 16-part multitimbrality with each part offering comprehensive programming across six parameter pages. These include standard performance parameters (volume, transpose, delay, effects assignment) and advanced features such as multiple pan options, output routing flexibility, and comprehensive MIDI filtering capabilities.

The unit features a new rotary speaker simulator with authentic speed ramping between fast and slow settings, mimicking real Leslie speaker behavior. Performance editing is enhanced by a large rotary dial with Enter/Exit buttons for intuitive parameter adjustment, replacing the hardware faders found on the keyboard versions.

TECHNICAL SPECIFICATIONS

Sound Generation

• Synthesis Type: PCM, Wavetables, Multiloop, Crossfade Multiwave and Subtractive Synthesis
• ROM Waveforms: 6MB (over 500 sounds in ROM vs. 350 in S2)
• Sample RAM: 2MB for user samples (expandable)
• Static RAM: Upgradeable for data retention (not available at review time)
• Oscillators: 32 total (16 pairs separable for extended polyphony)
• Polyphony: Up to 32 notes maximum with dynamic voice allocation and assignable priority
• Multitimbrality: 16-part multitimbral operation
• Layers/Splits: 16 layers with independent dynamic range, 16 split zones

Digital Signal Processing

• DACs: 6 x 18-bit Digital/Analog converters
• Effects Processors: 2 Digital Signal Processors
  • DSP1: Dedicated reverb processor
  • DSP2: Delays, flangers, choruses, and modulation effects
• Effects Libraries: 64 + 64 programmable effects
• Special Features: Rotary speaker simulator with variable speed ramping

Filters & Audio Processing

• Digital Filters: 32 programmable filters (2 per voice)
• Filter Types: 5 types with Resonance Q control
  • Low Pass, High Pass, Band Pass, Parametric Boost, Parametric Cut
• Audio Specifications:
  • S/N Ratio: >96dB (referenced to 'Sinus' waveform)
  • Dynamic Range: >96dB
  • Frequency Response: 10Hz - 18kHz
  • Sampling Rate: 41.7kHz
• Stereo Processing: Dynamic stereo panning capability

Memory & Data Management

• Sound Library: 518 ROM sounds + up to 1600 RAM sounds
• Performances: 100 programmable performances
• Songs: 10 song storage locations
• Operating System: Upgradeable via integral disk drive
• Sound Organization: MIDI 1.0 Version 4.2 compliant with multiple 128-sound banks
• Masking Function: Differentiates ROM sounds, Sample Translator sounds, and combinations

Sequencer Specifications

• Tracks: 16 tracks maximum
• Resolution: 192 Beats Per Quarter (BPQ)
• Capacity: Approximately 250,000 recordable events
• Editing Features:
  • Real-time and step-time recording
  • Overdub/Replace modes
  • Quantization with note range specification
  • Real-time delay compensation
  • Microscope editing (event-by-event)
  • Copy/erase functions between locator points and note ranges
  • Duplicate note deletion
  • Track copying between songs
• File Compatibility: Standard MIDI File loading and saving
• Background Operation: Background song loading (preload)

Sample Import Capabilities

• Supported Formats:
  • Sound Designer format
  • Avalon format
  • MMA Sample Dump Standard (over MIDI)
  • Akai S1000 disk format (direct reading)
• Sample Translator: Version 2 built into ROM (vs. optional on S2)
• Integration: Samples become part of machine's waveform library

Physical Interface

• Display: Large LCD (240 x 64 pixels, backlit)
• Controls: Nearly 50 buttons, large rotary dial with Enter/Exit buttons
• Front Panel Features: Internal 3.5" HD disk drive, comprehensive button layout
• Menu System: 8-item main menu with page memory retention
• Data Security: Impossible to lose editing data without explicit save/abort

Storage System

• Disk Drive: 3.5" High Density (1.62MB format capacity)
• Loadable Data Types:
  • PCM sample data
  • Sound libraries and individual sounds
  • Songs and performances
  • DSP effects settings
  • Standard MIDI Files
  • System software upgrades
  • Akai S1000 samples and programs
• Background Operation: Full background disk operations
• Compatibility: S2 disk reading capability (with limitations due to expanded ROM)

MIDI Implementation

• Channels: 16+16 independent MIDI channels
• Ports: 2 MIDI IN, 2 MIDI OUT, 2 MIDI THRU
• Special Features:
  • MIDI Merge capability
  • Clock In/Out
  • Sample transmission/reception via MMA Sample Dump Standard
• General MIDI: Full General MIDI compliance (switchable utility option)
• Multi Mode Programming: 16 voices/tracks with 6 parameter pages each
• MIDI Filtering: Two dedicated pages of MIDI filter options per track

Audio Outputs

• Total Outputs: 6 audio outputs plus headphones
• Main Outputs: Stereo pair (outputs 1+2) with effects (wet)
• Individual Outputs: 4 additional outputs configurable as:
  • Two additional stereo pairs
  • Four separate mono outputs
  • Combination of stereo pairs and mono outputs
• Output Routing: Programmable per voice/track
• Headphone Output: Dedicated headphone jack

Control Interface

• Foot Controls:
  • 1 dedicated volume pedal input
  • 2 assignable footswitch inputs
• Physical Controllers:
  • Large rotary dial with Enter/Exit confirmation
  • Numeric keypad for parameter entry
  • Nearly 50 dedicated function buttons

Internal Processing

• Main Processor: Motorola MC68302 (16MHz)
• System RAM: 2MB for data handling tasks (excluding sample RAM)
• Architecture: Computer-like system requiring disk-based data storage (unless Static RAM upgrade installed)

Physical Specifications

• Format: 3U rackmount module
• Dimensions: 434 x 132.5 x 276.5 mm (L x H x D)
• Weight: 7.3kg
• Back Panel Features: Knockout section for possible future expansion (possibly SCSI)

Upgrade Options

• Turbokit Retrofit: Available for S2/S3 keyboard owners
  • Professional installation required (complex soldering/modification)
  • Provides all S2R features to existing S2/S3 units
  • Includes socket preparation for Static RAM upgrade
• Static RAM Upgrade: Planned option for data retention without disk loading
  • Ready-socketed on Turbokit installations
  • Installation timing: To be determined

Compatibility & Legacy Support

• S2 Compatibility: Reads most S2 disks with limitations due to expanded ROM
• S2R to S2: Requires special software for S2 units to read S2R disks
• Sound Library Compatibility: S2R libraries cannot be read by S2 units
• Third-party Support: Growing availability of third-party sound libraries

Performance Characteristics

• Operating Modes: Single, Layer, Split, Multi
• Voice Priority: Assignable priority system with dynamic allocation
• Real-time Control: Comprehensive real-time parameter control via rotary dial
• Stage/Studio Use: Designed for both live performance and studio applications
• Sound Quality: Described as "clean, rich, and very usable" with exceptional clarity