TECH main core is a 8-bits CPU UPD78312 manages 16 voices polyphony based on LA synthesis - the relative DAC is a Burr-Brown model HP54HP.
D50 Linear Arithmetic is not like a wavetable synthesizer as no harmonic spectrograms are involved in this synthesis, instead, L.A is based on very short attack PCM transients for limiting memory usage. Psychoacoustic facts demonstrate that the "attack" segment is the most important part for the sound identification by human ear.
LA synthesis WG Wave Generator is a mix of 2 syntheses:
- Digitally generated basic waveforms (sawtooth & square waves) a kind of primitive VA (1)
- PCM wavetable (2)
STRUCTURE HIERARCHY the minimal part is the PARTIAL composed by 2 UPPER tones + 2 LOWER tones then 4 combined tones make a PATCH. TONE has value for relation between both partials and each partial is like an oscillator with various synthesis chain elements:
->WG (voice) + TVF (filter) + TVA (amplitude)
WAVE GENERATOR the WG system handles a 128 kb ROM (at IC29-30) PCM wavetable + a digital waveform generator.
- 47 Transient PCM acoustic
- 29 Transient PCM spectral loops
- 23 Transient PCM normal loops
2 digitally generated sawtooth and square wave
ALGORITHMS the WG combines partial synthesis elements with a digital ring modulator in 7 possible signal pathways or algorithms:
(p= pcm sample / s= digitally generated wave)
PERFORMANCE parameter CHASE is a special delay mode between the tones with 3 directions modes:
- Upper -> Lower
- Upper -> Lower -> Lower
- Upper ->Lower -> Upper
PATCH can be played also with a legato with variable portamento time.
MIDI quite basic but full MIDI exclusives is implemented with full support of edit and data dump.
FILTER structure is based on the TVF time variant filter which is a digital 4-poles resonant lowpass filter.
TECH filter has a restriction: TVF does not act on a PCM element later possible on V-synth D50 emulation.
LFO 3 delayed modulators (shapes: saw, triangle, random and square) and 3 destinations:
- LFO to amplitude
- LFO to pulse width
- LFO to filter cutoff.
ENVELOPE 2 main EGs:
- EG1 amplitude : 5 segments + 5 times
- EG2 filter : 5 segments + 5 times.
All partials have their own EG for both amplitude + filter, for a total of 4 TVF EGs and 4 TVA EGs.
EFFECTS 32 reverbs + 7 chorus modulations.
Effect can be balanced with dry / wet parameter to different tones in 3 modes:
mono tones with stereo reverb
- stereo tones with stereo reverb
- stereo Tones with reverb to upper or lower tone.
A simple serial -12 dB EQ with HIGH settings boost (250 Hz) or a LOW boost (63 Hz) + Q-emphasis.
MAINTENANCE the D-50 usually suffers from dead key contacts: get q-tips and cleaning solution to wash both contacts and strips and pay attention to remove also possible cotton debris. Aftertouch is more critical and may need more attention to fix the sensors.
64 RAM internal patches
no ROM sounds
RAM is doubled if using cards m-256E or m-256D.
RAM system included a Cr-2032 lithium battery in holder.
D-50 RELATED MODELS:
EDITOR many computer-based softwares are available:
D50 librarian (PC donationware) PIC
Soundquest (MAC/PC $$)
- EMC D50 editor manager (Atari ST) PIC
- Roland D50 parameter editor (Commodore Amiga) PIC
DR.T editor (Atari ST)
- Synth works (Atari ST) PIC
- D50 manager (Atari ST) PIC
- CTRLR (PC/MAC free) PIC
- D50v (VST editor) PIC
VST PLUGIN / SAMPLED VERSION there are some free and commercial samples set:
||200 MB free
D50 / D550 AUDIO TEST DEMO