Sub Phatty Controller

A simple Python application to control LFO Wave Shape and VCO 1 Octave on your Moog Sub Phatty via MIDI when physical switches are broken.

Features

• 6 LFO Wave Forms: Triangle, Square, Saw, Ramp, Sample & Hold, Filter Envelope
• 4 VCO Octaves: 16', 8', 4', 2' (correctly mapped according to MIDI spec)
• LFO Rate Control: Real-time slider control (CC #3, values 0-127)
• Web-based GUI: Works on Mac, iPhone, iPad - any device with a browser
• Command-line Interface: Quick commands for fast adjustments
• Mobile Optimized: Touch-friendly interface for live performance

Installation

1. Install Python Dependencies

Open Terminal and navigate to this folder, then run:

pip3 install -r requirements.txt

2. Connect Sub Phatty

• Connect your Sub Phatty to the computer via USB
• Make sure it's powered on and recognized as a MIDI device

3. Run the Application

Web Interface (Recommended):

python3 sub_phatty_web.py

Then open: http://localhost:8080 (or the IP address shown for mobile access)

Command Line Interface:

python3 sub_phatty_final.py

Usage

Web Interface

The web application provides:

LFO Wave Shape Buttons

• Triangle: Triangle wave
• Square: Square wave
• Saw: Sawtooth wave
• Ramp: Ramp wave (reverse sawtooth)
• Sample & Hold: Random stepped values
• Filter Envelope: Uses filter envelope as LFO source

LFO Rate Slider

• Range: 0-127 (Slow → Fast)
• Real-time: Immediate response and value display
• Touch-friendly: Optimized for mobile devices

VCO 1 Octave Buttons

• 16': One octave lower
• 8': Normal pitch
• 4': One octave higher
• 2': Two octaves higher

Command Line Interface

Quick Commands:

python3 sub_phatty_final.py lfo triangle    # Set LFO to triangle wave
python3 sub_phatty_final.py lfo square      # Set LFO to square wave
python3 sub_phatty_final.py lfo ramp        # Set LFO to ramp wave
python3 sub_phatty_final.py lfo filter_env  # Set LFO to filter envelope
python3 sub_phatty_final.py vco 16          # Set VCO to 16' octave
python3 sub_phatty_final.py vco 2           # Set VCO to 2' octave
python3 sub_phatty_final.py help            # Show help

Interactive Mode:

python3 sub_phatty_final.py

Mobile Access

1. Start the web server on your Mac
2. Note the IP address shown (e.g., http://192.168.68.81:8080)
3. Open that address on your iPhone/iPad browser
4. Control your Sub Phatty remotely!

Troubleshooting

"No MIDI ports found"

• Check that Sub Phatty is connected and powered on
• Try unplugging and reconnecting the USB cable
• Restart the application

"MIDI connection error"

• Close Moog Sub Phatty Editor if running (only one application can use the MIDI port at a time)
• Click "Reconnect MIDI" in the web interface
• Check that the Sub Phatty is recognized by your system

Settings don't change on the synthesizer

• Verify that Sub Phatty is set to MIDI channel 2 (this app uses channel 2, same as Sub Phatty Editor)
• Ensure MIDI over USB is enabled on the synthesizer
• Try power cycling the Sub Phatty

Web interface won't load

• Make sure no other application is using port 8080
• Check your firewall settings
• For mobile access, ensure both devices are on the same WiFi network

Technical MIDI Details

This application uses the following MIDI Control Change (CC) messages according to the official Moog Sub Phatty MIDI Implementation:

• LFO Wave Shape: CC #71
  • Triangle: 0, Square: 16, Saw: 32, Ramp: 48, Sample & Hold: 64, Filter Envelope: 80
• LFO Rate: CC #3 (values 0-127)
• VCO 1 Octave: CC #74
  • 16': 16, 8': 32, 4': 48, 2': 64

All messages are sent on MIDI channel 2 (same as Sub Phatty Editor).

Why This Project Exists

Physical switches on analog synthesizers can break over time. Rather than expensive repairs, this software solution provides:

• Better functionality than original switches (LFO rate control, more wave shapes)
• Remote control capability (perfect for live performance)
• Reliability - software doesn't wear out like mechanical switches
• Mobile access - control from phone/tablet while playing

Project Structure

Main Files (Required for Operation)

• sub_phatty_web.py - Web-based GUI controller (recommended)
• sub_phatty_final.py - Command-line interface
• midi-implementation.csv - Official Moog MIDI specification
• requirements.txt - Python dependencies
• README.md - This documentation

Utils Directory

The utils/ directory contains development tools, debug utilities, and test files used during project development. These are not needed for normal operation but can be useful for debugging or extending functionality.

See utils/README.md for detailed information about these tools.