What is sonicflow?

SonicFlow is a free, open-source macOS menu bar app that gives you separate volume controls for each application running on your computer. Instead of a single system volume knob that affects everything equally, SonicFlow lets you turn down a video call while keeping your music louder, or mute a specific app with a single click, all without leaving what you're doing. The app lives entirely in the menu bar and has no Dock icon. It shows every application currently producing audio in a small panel, with a slider for each one. There is also a master volume control that follows the standard keyboard volume keys. An auto-ducking feature automatically lowers other apps' volume by a configurable amount, defaulting to 50 percent, whenever a communication app is actively outputting voice. Under the hood, SonicFlow uses CoreAudio Process Taps, a low-level audio interception API built into macOS 14.2 and later, to capture each app's audio stream independently, apply the volume adjustment, and mix everything back to the speakers in real time. The original app's audio path to the speakers is silenced during capture so you don't hear double audio. This processing adds less than 1 percent CPU usage at idle and 1 to 2 percent during active audio. The project is written in Swift 6 and uses SwiftUI for its interface. It requires macOS 14.2 or later. The README does not state a license.