HiFiBerry DAC2 HD + DSP Control Panel

This is a React-based web UI for controlling the DSP functionality of the HiFiBerry DAC2 HD + DSP Add-on board. It uses the HiFiBerry DSP REST API and a SigmaStudio-generated DSP profile to provide real-time control of DSP parameters through a simple web interface.

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Features

• Control Master Volume
• Set Max Volume Limit
• Adjust Left / Right Channel Volume (Balance)
• Control Tone: Low, Mid, High frequencies
• Clean UI for real-time control from web browser / mobile device
• Runs as a background service on Raspberry Pi

UI Control Panel

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Services and Integration

The repository also contains systemd service definitions to ensure proper startup and integration with MoodeAudio OS and HiFiBerry components.

Included Services

Service File	Description
audio-trigger.service	Turns amplifier ON/OFF based on audio stream activity in MoodeAudio OS
dsp-control-panel.service	Runs the React UI app as a system service
sigmatcpserver.service	Starts SigmaTCPService, required for DSP parameter writes

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Getting Started

1. Install Dependencies

Make sure Node.js and npm are installed on your Raspberry Pi. Then install the UI dependencies:

cd dsp-control-panel
npm install

2. Build the UI

npm run build

3. Deploy the App as a Service

Copy the systemd service files to /etc/systemd/system.

4. Set Up Services

sudo systemctl enable sigmatcpserver.service
sudo systemctl enable dsp-control-panel.service
sudo systemctl enable audio-trigger.service

sudo systemctl start sigmatcpserver.service
sudo systemctl start dsp-control-panel.service
sudo systemctl start audio-trigger.service

SigmaStudio Integration

The DSP logic for this project is defined in the SigmaStudio project:

.\sigma-studio-profile\dsp-addon-my4.dspproj

This profile is compiled and exported for use with the HiFiBerry DSP Add-on board. It defines the signal routing, processing blocks, and external controls exposed to the UI through SigmaTCPService.

Functional Blocks

The DSP profile includes:

• Input stage: Handles stereo input from the DAC2 HD I2S input
• Master Volume: External volume block (e.g., Single Slew Ext Vol) mapped for REST API control
• Left / Right Channel Volumes: Separate external volume blocks for balance control
• Max Volume Limiter: Gain block with upper bound, also exposed externally
• Tone Controls:
  • Low Shelf Filter
  • Mid Peaking Filter
  • High Shelf Filter
    All are parameterized via external controls
• Mute: External boolean control to bypass audio
• Output stage: Connects to the DAC output via the DSP Add-on

API Integration

Each externally controllable block in SigmaStudio is configured with read/write external parameters, which are accessible via HiFiBerry's REST API (served by SigmaTCPService).

These parameters are mapped to UI elements in the React app for real-time control.

DSP Diagram

The full signal path and block layout can be seen in the screenshot:

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License

MIT License