Roland D-550 (1987)
Polyphonic digital synthesizer module with PCM and synth waveforms, ring modulation, resonant filter, pitch/TVA/TVF envelopes, three LFOs per tone, 2x EQ, 2x chorus and reverb units. One of Roland's very first completely digital synthesizers featuring the Linear Arithmetic (LA) synthesis.
Synthesis
Structure
- Patch: consists of two tones (layer/split)
- Tone: 7 tone structures combining two partials, pitch envelope, three LFOs, ring modulator and EQ into a tone
- Partial: includes wave generator, TVF with envelope, TVA with envelope
Wave generator (WG)
- Type: PCM (ROM waveforms), synth (saw and square with PWM)
- 5-stage pitch envelope
Filter (TVF)
- Resonant digital low-pass filter
- 5-stage TVF envelope
LFO
- Type: triangle, sine, square, sample and hold
- Destination: WG pitch, WG PW, TVF cutoff, TVA level
- LFO delay, key sync
TVA
- 5-stage TVA envelope
Memory
- 100 PCM ROM waves
- 64 internal, 64 card patch locations
Effects
- Two-band EQ (low, parametric mid) and chorus (8 types) per tone
- Global reverb processor (32 reverb types)
Controls
- 40x2 symbol backlit LCD
Connections
- Line, headphone outputs
- MIDI in/out/thru
