The Korg TR-Rack is a professional 1U rackmount synthesizer module that brings the advanced synthesis technology of Korg's flagship Trinity workstation series to a more accessible price point. Released in 1998 at about USD1000, this module delivers the Trinity's renowned ACCESS (Advanced Control Combined Synthesis System) synthesis and multi-effects technology in a compact, silver-cased rack format.

The TR Rack represents Korg's traditional approach of creating rackmount alternatives to their workstation ranges, allowing musicians to access the core synthesis capabilities without investing in a full workstation setup. Despite being more affordable than the Trinity workstation, the TR Rack actually offers enhanced capabilities with 32MB of sound ROM (8MB more than the Trinity) and twice as many built-in Programs, Combis, and Drumkits.

Synthesis Architecture

The module employs sample-based subtractive synthesis using Korg's mature ACCESS technology. Each Program features two oscillators, with each oscillator routed through dedicated filter and amplifier sections. The architecture includes comprehensive five-stage pitch, filter, and amplitude envelopes, plus pitch and filter LFOs for each oscillator. The system supports both single/double oscillator modes and drum modes, with the ability to assign any of the module's Drumkits to a Program.

Notable synthesis features include velocity switching between two Multisamples per oscillator with user-definable switch points, and enhanced drumkit programming with velocity switching between two drum sounds per key. The sophisticated filtering system offers multi-mode resonant filters with low-pass, high-pass, band-pass, and band-reject types, plus velocity-controllable resonance.

Effects System

The TR Rack features an exceptionally versatile multi-effects architecture based on a mixing desk-style arrangement of Master (send/return) and Insert effects. The system provides 14 Master effects and an impressive 100 Insert effects to choose from. Master effects include reverb/delay and modulation processors shared across all Programs, Combis, and Multi Tracks. Insert effects can be configured in series, with complex routing possibilities and dynamic modulation capabilities using 26 different modulation sources.

Effects are classified by size (1, 2, or 4) based on their mono/stereo configuration, with a total combined size limit of 8 per Program/Combi/Multi, allowing flexible trade-offs between number of effects and number of parts affected.

Performance Modes

The module operates in three distinct performance modes:

• Program Mode: Single part/channel operation
• Combination Mode: Up to eight Timbres/channels for complex split/layer textures
• Multi Mode: 16 Tracks/channels for MIDI sequencing applications

User Interface and Control

The front panel features a large 2x20-character backlit LCD with unusually large lettering for excellent readability, even from several feet away. While the Trinity's graphical touch-screen is absent, the clear display makes navigation straightforward. Front-panel controls include mode selection, parameter editing, and utility functions, though full synthesis parameter editing requires the included SoundDiver software for PC/Mac.

The module includes convenient features like category-based sound browsing, with 16 different sound categories for both Programs and Combis, and an A4 button for auditioning sounds without a connected keyboard.

Connectivity and Integration

Beyond standard MIDI connections, the TR Rack includes a "To Host" serial port for direct computer connection without requiring a separate MIDI interface. The rear panel provides stereo main outputs plus two separate audio outputs for external effects processing. An optional DI-TRI digital audio interface board enables ADAT-format digital output transmission.

Sound Content

The module ships with extensive sound content across four banks:

• 512 Programs (128 x 4 banks) spanning 15 categories from keyboards and organs to synth leads and sound effects
• 512 Combis (128 x 4 banks) covering 16 categories including pads, splits, orchestral sounds, and complex textures
• 24 Drumkits ranging from standard acoustic sets to specialized electronic, ethnic, and processed kits

The additional 8MB of ROM compared to the Trinity provides 40 new Multisamples and 200 new drum samples, with particular emphasis on enhanced bass and snare drum collections. Notable sounds include stereo-sampled acoustic piano, rich analog-style synthesis patches, and atmospheric textures that showcase Korg's characteristic warm, full, and dynamic sound palette.

Technical Specifications

Core Synthesis

• Synthesis Method: ACCESS sample-based subtractive synthesis
• Polyphony: 32 oscillators (32-voice with single-oscillator Programs, 16-voice with double-oscillator Programs)
• Multitimbrality: 16 parts (Multi mode), 8 parts (Combi mode)
• Sound ROM: 32MB PCM samples
• Sampling Rate: 48kHz

Architecture

• Oscillators: 2 per Program
• Filters: Multi-mode resonant filters per oscillator (low-pass, high-pass, band-pass, band-reject)
• Envelopes: 5-stage pitch, filter, and amplitude envelopes per oscillator
• LFOs: Pitch and filter LFOs per oscillator
• Modulation: AMS (Alternate Modulation Source) matrix with 26 sources, 27 destinations

Sound Memory

• Programs: 512 (128 × 4 banks)
• Combinations: 512 (128 × 4 banks)
• Drumkits: 24 total (11 from Trinity + 11 new + 2 user)
• Multisamples: 40 additional (beyond Trinity's content)
• Drum Samples: 200 additional

Effects System

• Insert Effects: 100 types
• Master Effects: 14 types (reverb/delay and modulation)
• Effect Configuration: Series routing for Insert effects
• Effect Sizing: Size 1, 2, and 4 classifications (max combined size of 8 per Program/Combi/Multi)
• Dynamic Modulation: 26 modulation sources for real-time effect control

Display and Interface

• Display: 2 × 20-character backlit LCD with large lettering
• Front Panel Controls: Mode selection, page/parameter navigation, edit functions, compare/write/reset
• Special Functions: A4 note play button, category browsing, MIDI activity LED

Connectivity

• Audio Outputs:
  • L/Mono and Right stereo audio jacks (main outputs)
  • Two separate audio jacks (additional outputs)
  • Stereo headphone jack
• MIDI: In, Out, Thru (standard 5-pin DIN)
• Computer Interface: "To Host" serial port (PC/Mac direct connection)
• Digital Audio: Optional DI-TRI board (ADAT format output + 48kHz wordclock input)
• Power: AC power input socket

Physical Specifications

• Format: 1U rackmount (19-inch)
• Casing: Silver finish
• Weight: 2.8kg
• Dimensions: Standard 1U rack height

Software and Expansion

• Included Software:
  • Emagic SoundDiver Trinity editor/librarian (PC/Mac)
  • Korg MIDI driver software (PC/Mac)
• Expansion Options: DI-TRI digital audio interface board only
• Editing Limitations: Full synthesis parameter editing requires computer software (not available from front panel)

Performance Modes

• Program Mode: Single part/channel
• Combination Mode: Up to 8 Timbres/channels
• Multi Mode: 16 Tracks/channels (MIDI sequencing)

Sound Categories

Programs (15 Categories)

Keyboard, Organ, Mallet, Bell, Strings, Vocal/Airy, Brass, Woodwind/Reeds, Guitar, Bass, Plucked Synth, Synth Lead, Motion Synth, Sound Effect, Drums/Percussion

Combis (16 Categories)

Pad & Lead, Bass, Splits, Breathy/Airy, Bell & Mallet, Motion Synth, Keyboard Synth, Strings, Orchestral, Horn Section, Guitar, Bass, Ethnic/Trad, Organ, Complex, Drums/Special FX

Drumkits (22 Total)

Standard, Processed, Jazz/Brush, Analog/Club (Mega-Mix), Psycho, BassDrum&Snares, Toms&Cymbals, Percussion, Orchestra&Ethnic, 01/W Total, 01/W Producer's, Vintage Kit, Ezer Goodie, WellArrrd, Hip-Hop/Rap, Pop/R&B, Jazz/Funk/Reggae, House/Techno, Industry/Analog, Funk Drummin', Aggressiv Vox

Tags: digital synthesizer