SoundSync

A lightweight, low-latency C# WPF application that captures your system's audio and routes it to multiple hardware output devices simultaneously. Built entirely on the Windows Core Audio API (WASAPI) using the NAudio library.

demo.mp4

✨ Features

• Multi-Endpoint Routing: Play a single audio source (like a YouTube video or Spotify or any audio source) through multiple headphones or speakers at the exact same time.
• Aggressive Latency Control: Implements a custom ring-buffer clearing strategy to combat hardware clock drift, ensuring secondary devices stay within ~10-30ms of real-time.
• Anti-Feedback Loop Protection: Automatically detects your default Windows playback device and prevents audio from being routed back into it, completely eliminating infinite echo loops.
• Dynamic Device Scanning: Easily refresh the device list to detect newly plugged-in USB or Bluetooth headphones without restarting the app.
• Modern UI: Built with Windows Presentation Foundation (WPF) featuring a sleek, dark-mode graphical interface.

⚙️ How it Works

The application uses WasapiLoopbackCapture to intercept the raw audio bytes flowing to your default Windows audio endpoint.

When the user clicks "Connect", the app initializes a separate WasapiOut stream for every selected hardware device in Shared Mode. As Windows fires DataAvailable events containing the live audio bytes, the application aggressively broadcasts those bytes into a BufferedWaveProvider attached to every selected output.

🚀 Getting Started

📥 Download & Installation (For Regular Users)

You do not need to install anything to use SoundSync!

1. Go to the Releases Page.
2. Download SoundSync-Portable.exe.
3. Double-click the file to run it. That's it!
4. If you face any issue, open the application with "Run as Administrator".

(Note: If you download the smaller SoundSync-Light.exe version, you must have the .NET 8.0 Desktop Runtime installed on your PC).

💻 Building from Source (For Developers)

1. Clone the repository:

   git clone https://github.com/sugumar247/SoundSync.git

2. Open SoundSync.slnx in Visual Studio 2022.
3. The project relies on the NAudio library. Visual Studio should restore this NuGet package automatically. If not, run:

   dotnet restore

4. Press F5 to compile and run the application.

🎧 Usage & "Perfect Sync" Tutorial

If you are trying to share a movie with a friend using two pairs of headphones, you will notice a slight ~30ms delay on the 2nd pair of headphones if you capture audio directly from the 1st pair.

To achieve 100.00% perfect synchronization with zero echoes, use the "Dummy Hardware" trick:

1. Look at your Windows sound settings and find an audio device you aren't currently using (e.g., an HDMI Monitor with no speakers, or a Virtual Audio Cable like VB-Audio Cable).
2. Set that silent device as your Default Windows Output. (Your computer will go silent).
3. Open SoundSync.
4. Check the boxes for Headphone 1 and Headphone 2 or more.
5. Click Connect.

The app will now capture the silent audio stream, duplicate it, and push it to both sets of headphones via the C# engine. Because they share the exact same routing path, their latency is identical and they are perfectly synchronized!

🛠️ Built With

• C# / .NET 8.0 - The core framework
• WPF - UI Framework
• NAudio - Audio and WASAPI interaction

🤝 Contributing

Contributions, issues, and feature requests are welcome!

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📝 License

Distributed under the MIT License. See LICENSE for more information.