- 2017-04-09 ISGK Instruments
- https://github.com/risgk/digital-synth-vra8-p/tree/vra8-px
- 3 Voice Pseudo Polyphonic Synthesizer for Arduino Uno
- A Variant of Digital Synth VRA8-P https://github.com/risgk/digital-synth-vra8-p
- Cutoff Velocity Sensitivity
- Detune EG Amount
- Phase Resolution: 24 bit
- Internal Signal Processing: 16 bit
- Audio Output (8 bit) with Error Diffusion
- Sub Oscillators (Triangle Wave)
- Changeable Osc 2 (Detune) Level
- Resonance with Q = 11.3 (Max)
- Velocity Sensitivity
- 3 Voice Pseudo Polyphonic Synthesizer (Paraphonic Synthesizer), MIDI Sound Module
- Serial MIDI In (38400 bps), PWM Audio Out (Pin 6), PWM Rate: 62500 Hz
- We recommend adding a RC filter circuit to reduce PWM ripples
- A cutoff frequency 10.6 kHz (R: 150 ohm, C: 100 nF) works well
- CAUTION: Click sounds may occur when you connect the audio out to an amp/a speaker or reset the board
- CAUTION: The Arduino PWM audio output is a unipolar LINE OUT
- Please connect this to a power amp/a headphone amp (not to a speaker/a headphone directly)
- Sampling Rate: 15625 Hz, Bit Depth: 8 bit
- LPF Attenuation Slope: -12 dB/oct
- Recommending Hairless MIDI<->Serial Bridge to connect PC
- Files
DigitalSynthVRA8Px.inois a sketch for Arduino/Genuino Unomake-sample-wav-file.ccis for Debugging on PC- Requiring GCC (G++) or other
make-sample-wav-file-cc.batmakes a sample WAV file (working on Windows)
generate-*.rbgenerate source files- Requiring a Ruby execution environment
- CAUTION: Use Arduino IDE 1.8.1 or later
- Parameter Editor (MIDI Controller) for VRA8-Px, Web App
- We recommend Google Chrome, which implements Web MIDI API
- VRA8-Px CTRL includes PRESET programs
- Recommending loopMIDI (virtual loopback MIDI cable) to connect VRA8-Px
- CAUTION: Low CUTOFF with high RESONANCE can damage the speakers
+---------------+------+----------------+----------+----------------+-----------------------------+
| Controller | Init | Value 0 | Value 64 | Value 127 | Notes |
+---------------+------+----------------+----------+----------------+-----------------------------+
| UNISON/MIX | 8 | OFF | ON | ON | 3 Voice Unison |
| | | +100% | -100% | +100% | Osc 2 (Detune) Level |
| WAVEFORM/SUB | 16 | Sawtooth | Organ | Square | Waveform |
| | | 100% | (0%) | 100% | Sub Osc Level |
| DETUNE | 64 | 0.06 Hz | 1.0 Hz | 3.8 Hz | |
| DETUNE EG AMT | 0 | -126 (EG 100%) | 0 | +125 (EG 100%) | Modulates DETUNE |
| AMP EG | 0 | OFF | ON | ON | |
+---------------+------+----------------+----------+----------------+-----------------------------+
| CUTOFF | 64 | 0.22 kHz | 1.2 kHz | 7.0 kHz | Range 4 to 124 |
| RESONANCE | 64 | Q = 0.7 | Q = 2.8 | Q = 11.3 | |
| CUTOFF EG AMT | 96 | -126 (EG 100%) | 0 | +125 (EG 100%) | Modulates CUTOFF |
| EG DECAY | 64 | 34 ms | 2.2 s | 8.7 s | Decay Time |
+---------------+------+----------------+----------+----------------+-----------------------------+
| VELOCITY SENS | 0 | 0% | 50.4% | 100% | Gain Velocity Sensitivity |
| CUTOFF V SENS | 127 | 0% | 50.4% | 100% | Cutoff Velocity Sensitivity |
+---------------+------+----------------+----------+----------------+-----------------------------+
[Experimental Synthesizer] Date: 2017-04-09
Model Digital Synth VRA8-Px MIDI Implementation Chart Version: 1.2.2
+-------------------------------+---------------+---------------+-----------------------+
| Function... | Transmitted | Recognized | Remarks |
+-------------------------------+---------------+---------------+-----------------------+
| Basic Default | x | 1 | |
| Channel Changed | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Mode Default | x | Mode 3 | |
| Messages | x | x | |
| Altered | ************* | | |
+-------------------------------+---------------+---------------+-----------------------+
| Note | x | 24-84 | |
| Number : True Voice | ************* | 24-84 | |
+-------------------------------+---------------+---------------+-----------------------+
| Velocity Note ON | x | o (V=1-127) | |
| Note OFF | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| After Key's | x | x | |
| Touch Ch's | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Pitch Bend | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Control 16 | x | o | UNISON/MIX |
| Change 17 | x | o | WAVEFORM/SUB |
| 18 | x | o | DETUNE |
| 19 | x | o | AMP EG |
| 20 | x | o | CUTOFF |
| 21 | x | o | RESONANCE |
| 22 | x | o | CUTOFF EG AMT |
| 23 | x | o | EG DECAY |
| 24 | x | o | VELOCITY SENS |
| 25 | x | o | CUTOFF V SENS |
| 27 | x | o | DETUNE EG AMT |
+-------------------------------+---------------+---------------+-----------------------+
| Program | x | x | |
| Change : True # | ************* | | |
+-------------------------------+---------------+---------------+-----------------------+
| System Exclusive | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| System : Song Pos | x | x | |
| Common : Song Sel | x | x | |
| : Tune | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| System : Clock | x | x | |
| Real Time : Commands | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Aux : Local ON/OFF | x | x | |
| Messages : All Notes OFF | x | o (123-127) | |
| : Active Sense | x | x | |
| : Reset | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Notes | |
| | |
+-------------------------------+-------------------------------------------------------+
Mode 1: Omni On, Poly Mode 2: Omni On, Mono o: Yes
Mode 3: Omni Off, Poly Mode 4: Omni Off, Mono x: No