- 2016-09-22 ISGK Instruments
- https://github.com/risgk/digital-synth-vra8-p
- 3 Voice Pseudo Polyphonic Synthesizer for Arduino Uno
- 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
- Sampling Rate: 15625 Hz, Bit Depth: 8 bits
- LPF Attenuation Slope: -12 dB/oct
- Recommending Hairless MIDI<->Serial Bridge to connect PC
- Files
DigitalSynthVRA8P.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
- Parameter Editor (MIDI Controller) for VRA8-P, Web App
- We recommend Google Chrome, which implements Web MIDI API
- VRA8-P CTRL includes PRESET programs
- Recommending loopMIDI (virtual loopback MIDI cable) to connect VRA8-P
- CAUTION: Click sounds may occur when you change the controllers (especially AMP EG and FILTER CUTOFF)
- CAUTION: Low FILTER CUTOFF with high FILTER RESO can damage the speakers
+---------------+----------------+----------+----------------+-----------------+
| Controller | Value 0 | Value 64 | Value 127 | Notes |
+---------------+----------------+----------+----------------+-----------------+
| UNISON | OFF | (ON) | ON | 3 Voice UNISON |
| OSC WAVEFORM | SAW (SAWtooth) | ORGAN | SQ (SQuare) | |
| OSC DETUNE | 0.24 Hz | 2.1 Hz | 3.8 Hz | |
| AMP EG | OFF | (ON) | ON | |
+---------------+----------------+----------+----------------+-----------------+
| FILTER CUTOFF | 0.22 kHz | 1.2 kHz | 7.0 kHz | Range 4 to 124 |
| FILTER RESO | Q = 0.71 | Q = 1.4 | Q = 2.6 | RESOnance |
| FILTER EG AMT | -125 (EG 100%) | 0 | +124 (EG 100%) | Modulate CUTOFF |
| EG DECAY | 21 ms | 1.4 s | 5.4 s | DECAY Time |
+---------------+----------------+----------+----------------+-----------------+
[Experimental Synthesizer] Date: 2016-09-22
Model Digital Synth VRA8-P MIDI Implementation Chart Version: 1.0.1
+-------------------------------+---------------+---------------+-----------------------+
| Function... | Transmitted | Recognized | Remarks |
+-------------------------------+---------------+---------------+-----------------------+
| Basic Default | x | 1 | |
| Channel Changed | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Mode Default | x | Mode 3 | |
| Messages | x | x | |
| Altered | ************* | | |
+-------------------------------+---------------+---------------+-----------------------+
| Note | x | 0-127 | |
| Number : True Voice | ************* | 24-84 | |
+-------------------------------+---------------+---------------+-----------------------+
| Velocity Note ON | x | x | |
| Note OFF | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| After Key's | x | x | |
| Touch Ch's | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Pitch Bend | x | x | |
+-------------------------------+---------------+---------------+-----------------------+
| Control 16 | x | o | UNISON |
| Change 17 | x | o | OSC WAVEFORM |
| 18 | x | o | OSC DETUNE |
| 19 | x | o | AMP EG |
| 20 | x | o | FILTER CUTOFF |
| 21 | x | o | FILTER RESO |
| 22 | x | o | FILTER EG AMT |
| 23 | x | o | EG DECAY |
+-------------------------------+---------------+---------------+-----------------------+
| 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 | |
| : 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