Humours: Alchemical Modeling
*Still under development.
Humours is a sound processing module based on the Teensy 4.0 with high performance Codecs and more than 20 seconds of 16bit stereo delay memory. The module can be used in alternate modes for reverb, delay, granular synthsis, physical modeling (Karplus-Strong), spectral processing, etc. With the Teensy audio library there are many different sonic possibilities.
Audio input, output, send and return are handeled by a pair of WM8731 audio codecs running at 16bit 44.1kHz.
The SD card links to the Teensy through the full 4bit interface for maximum throughput. Used for loading samples and recording a buffer for granular effects. Can also be used to store start up parameters and mode before shutdown.
The 8 CVs are buffered through MCP6004 OpAmps to a MAX1300 16bit ADC.
The 4 main and 8 CV potentiometers go through a pair of 4051 analog multiplexers to the 12 bit (4096 steps) ADCs on the Teensy 4.0. This allows for variable responses for the attenuverters/attenuators and the main parameters. Also gives the possiblity of 12 parameters independent from the 8 CVs inputs.
The 4 of the buttons and gates are likewise are read through a 4051 multiplexer. They are independent from the gate inputs so they can be used as alternate functions or mode switching. The central gate may act as either an input or output with clamping and level shifting. The output will be useful as an end of sample/cycle or rate indicator.
The 13 RGB LEDs are WS2812 (neopixels) that use a single wire non-blocking protocol.
RAM can be expanded with up to 8 SPI SOCI-8 ICs (SPI1). Some options are: 23LC1024 with 1Mbit $2, IS62WVS2568 with 2Mbit $3, and IS62WVS5128 4Mbit $5. 1Mbit gives roughly 1.4s of delay, so with 32Mbit there is 22.4s of stereo buffer.
License
All code developed for the Humours will be licensed CC BY-NC-SA 4.0 and provided in a repository. The code inherited from the Arduino and Teensy libraries will respect their respective licenses. Panel files and panel art is also under CC BY-NC-SA 4.0. This is a permisive license that allows for attributed non-comercial remixes under the same license.
The schematics are under a CC BY-NC-ND 4.0 license. For use in DIY and debuging, not for use in creating alternate versions of Humours.
The board files are all rights reserved and will not be provided. The reasoning is that Sin Phi will be expected to support clones and derivatives of their product without being able to control the implementation. Boards will be availible through DIY synth retailers.
Schematic
Full schematics for the IO and main boards are provided for debugging purposes. Sin Phi will not support any 3rd party boards produced from these schematics.
Front Panel
The front panel is designed to be made by a PCB fabricator. It is double sided to minimize the waste panels due to blemishes. Legends are made by using solder mask to expose the copper layer. Full copper layers front and back to increase panel stiffness. Mounting holes are 0.3" from the panels edge at each side. Modifications and enhancements of the panel design are encouraged!
PCB Layout
Bill of Materials
This is built around the Teensy 4.0, availible from PJRC and retailers. Knobs should be close to 0.5" in diameter and matched to your potentiometer shaft type. Davies 1900h, Rogan 1PS, and Sifam small unskirted would all be suitable. The project materials cost is likely to be ~$200.
Tuning and Calibration
No tunning or calibration should be required. A calibration routine can be performed when all 5 gate buttons are held. Remove all patch cables and set all poteniomters to full counter clockwise before begining calibration.
Pin Assignments
Max 1300 ADC
0 - SPI CS, 1 - SPI MISO, 26 - SPI MOSI, 27 - SPI SCK
WM8731 Codec x2
16 - I2C SCL, 17 - I2C SDA, 7 - I2S Out Digital 1, 8 - I2S In Digital 1, 2 - I2S Out Digital 2, 5 - I2S In Digital 2, 20 - I2S LRCLK, 21 - I2S BCLK, 23 - I2S MCLK
SRAM & 74LSX138
11 - SPI MOSI, 12 - SPI MISO, 13 - SPI SCK, 28 - A2, 30 - A1, 32 - A0
8051 Mux x3
3 - B, 4 - A, 6 - C, 10 - Common Button, 25 - ADC 1, 22 - ADC 2
Other
9 - Sun Button, 15 - Sun Gate
14 - Neopixel
25 - Normilization Probe
I2C Expander
18 - I2C SDA, 19 - I2C SCL
Panel Legend
Audio In
♄ Saturn
Audio Out
♅ Uranus
Audio Send
⚴ Pallas
Audio Return
⚳ Ceres
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Control Voltage and Attenuverters
☌ Conjunction
Gates and Buttons
♀ Venus
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Patch Programming
The Humours module is able to perform more than a dozen different functions. Alternate modes can be accessed by holding the sun button and selecting a 4 bit code from the other buttons. Releasing the sun button will trigger the mode switch. Be aware the sun gate may switch between input or output depending on mode.
Stereo Reverb
Size
Depth
Color
Decay
Mix
Speed
Pre-Delay
Absorb
Granular Synthesis
Pitch
Inputs in, outputs out.
Speed
Position
Size
Density
Overlap
Window
Blend
Karplus-Strong
Frequency
Inputs in, outputs out.
Structure
Harmonics
Position
Tone
Timbre
Formant
Cutoff
Stereo Delay
Time
Feedback
Modulation
Wet/Dry
Noise Types
-6dB/Oct Brown/Red, -3dB/Oct Pink (equal energy per octave), Psychoacoustic Grey (precieved equal energy per octave), 0db/Oct White (equal energy per frequency), +3db/Oct Blue, and fluctuating random.
Specifictations
Width | Depth | +12 V | -12 V | +5 V |
18 hp | 40 mm | 20 mA | 10 mA | 200mA |