The Roland D-50 Linear Digital Synthesizer arrived in 1987 as Roland’s first fully digital synthesiser and introduced the company’s newly developed Linear Arithmetic, or LA, synthesis system. Rather than relying exclusively on conventional digital waveforms or attempting to reproduce complete instruments through sampling, the Roland D-50 combined digitally generated synthesiser waveforms with short PCM sampled elements. This architecture allowed complex transient information from acoustic and percussive sounds to be combined with fully synthesised components, providing a flexible approach to creating both recognisable instrument characteristics and entirely new sounds.
At the centre of the Roland D-50 architecture were 32 Partials. Two Partials could form a Tone, with Upper and Lower Tones combined to create a Patch. The Roland D-50 provided seven Structure configurations that determined how its Synthesizer Sound Generator and PCM Sound Generator were combined. Structures could mix two Partials directly or employ a Ring Modulator to create additional harmonic complexity. The PCM section incorporated 4 megabits of waveform memory containing 100 sound components derived from processed samples.
The synthesiser-generated Partials offered a digital signal path structured around familiar synthesis functions. These included pitch, waveform and pulse-width parameters, Time Variant Filter processing with cutoff frequency, envelope and resonance controls, Time Variant Amplifier processing and three Low Frequency Oscillators. PCM Partials could be combined with these synthesised elements through the Structure system, allowing sampled attacks or complex waveforms to be paired with programmable sustaining components.
This combination was fundamental to LA synthesis. Instead of consuming large amounts of sample memory reproducing an entire sound, the Roland D-50 could use PCM material for complex portions of a sound while generating other elements algorithmically. The result was a synthesis system capable of building sounds from numerous individually controlled components rather than simply playing back complete recordings.
Each Roland D-50 Patch could contain Upper and Lower Tones, and the keyboard offered Whole, Dual, Split and Separate operating modes. Whole mode could provide up to 16 simultaneous notes from a single Tone, while Dual mode combined Upper and Lower Tones with up to eight notes sounding simultaneously. Split and Separate modes provided additional arrangements for assigning the two Tones across the keyboard and MIDI system.
The Roland D-50 also integrated digital effects directly into the instrument. Its effects system incorporated two 2-band parametric equalisers, two stereo chorus processors and digital reverb. The chorus section provided eight modes, including chorus, flanger and tremolo treatments, while the reverb system offered 32 types. Roland combined these processing stages with 28-bit internal signal processing and 20-bit D/A conversion.
The effects were integrated into the Patch architecture rather than being treated simply as an external addition. This allowed a complete programmed sound, including its synthesis parameters and processing, to be recalled from memory. The combination of synthesis and onboard processing was a particularly important part of the Roland D-50 design because it allowed finished sounds to be created within a single keyboard without requiring separate chorus, equalisation and reverb processors.
Patch storage was equally comprehensive for the period. The Roland D-50 provided 64 internal Patches, with a further 64 available from a Memory Card. An M-256D RAM Memory Card could store user-created sounds, while ROM cards could provide additional read-only sound libraries. The ROM card supplied with the Roland D-50 contained the factory preset programs as a backup.
Programming was handled through an illuminated 80-character LCD, arranged as two lines of 40 characters, together with a menu-based interface and a joystick. Parameters could be selected and edited from the front panel, while comparison, copy, undo and recall functions aided sound development. The joystick provided real-time control of Partial balance and parameter values and could manipulate more than one value simultaneously.
The Roland D-50 keyboard comprised 61 velocity-sensitive and pressure-sensitive keys. Performance functions included a combined Bender/Modulation lever, aftertouch sensitivity adjustment, portamento, chase, key transpose and programmable keyboard modes. Upper and Lower Tones could also be assigned to separate MIDI channels when required.
For musicians requiring more immediate access to synthesis parameters, Roland offered the optional PG-1000 Programmer. The Roland PG-1000 incorporated 56 editing knobs arranged into sections corresponding to the Roland D-50’s four Partials and common parameters. It allowed multiple parameters and Partials to be edited simultaneously and communicated with the Roland D-50 through MIDI.
The Roland D-50 occupies an important position in synthesiser history because it represented Roland’s decisive move into fully digital synthesis. Roland identifies the Roland D-50 as its first fully digital synthesiser and records that it became a worldwide success following its introduction in 1987.
Its LA synthesis system also helped establish an approach that would become fundamental to subsequent generations of digital instruments: combining sampled material with synthesised waveforms rather than treating sampling and synthesis as entirely separate technologies. Sound On Sound subsequently characterised the Roland D-50 as an early landmark of the sample-plus-synthesis approach that became widespread in later digital synthesisers and workstations.
The integration of digital effects was equally significant. Roland identifies the Roland D-50 as the first performance synthesiser to incorporate DSP effects, combining synthesis with chorus, reverb and equalisation inside the instrument. At a time when comparable processing would normally have required external studio equipment, this allowed a Patch to include much of the processing required to produce a finished sound. The factory sound library became another important part of the Roland D-50’s influence. Roland identifies presets including Fantasia and Calliope as sounds that became associated with major recordings of the late 1980s. Eric Persing was one of the principal sound designers involved with the Roland D-50, while Adrian Scott also participated in sound creation and evaluation during development.
The Roland D-50 therefore represented more than a change in Roland’s synthesis technology. Its combination of PCM elements, programmable digital synthesis, onboard effects, extensive patch memory and performance control anticipated the integrated digital synthesiser architecture that became increasingly common during the closing years of the 1980s and throughout the 1990s.
Features
- Linear Arithmetic synthesis combining PCM and synthesised sound generation
- 32-Partial architecture with seven Structure configurations
- 4-megabit PCM waveform memory with 100 sound components
- Upper and Lower Tone architecture with Whole, Split, Dual and Separate keyboard modes
- Built-in 2-band parametric equalisation, stereo chorus and digital reverb
- 64 internal Patches with an additional 64 Patches available from Memory Card
- 61-key velocity-sensitive and pressure-sensitive keyboard
- Illuminated 80-character LCD and joystick-based parameter control
- Comprehensive MIDI In, Out and Thru connectivity
- Optional Roland PG-1000 Programmer for direct parameter editing
