What is system audio?

System audio refers to any sound produced inside the computer and routed to its speakers or audio output: a video playing in a browser, a game's soundtrack, a notification chime, or music from a streaming app. It is distinct from microphone audio, which captures sound from the surrounding environment. When people say they want to record 'internal audio,' they usually mean capturing this system output directly and cleanly, without picking it up through a mic and losing quality to room noise, echo, or background sound.

Capturing system audio matters most for tutorials, product demos, and gameplay clips where the on-screen sound is part of the story. On macOS, apps cannot record system audio through a native API alone; Apple does not expose internal sound to third-party recorders by default. Creators typically install a loopback or virtual audio-device tool (such as BlackHole or Loopback) that reroutes the computer's output back in as a recordable input. That virtual device then feeds the recorder or an editor, letting the internal sound be saved alongside or separately from the video.

Limelight is a visual-only screen recorder: it focuses entirely on picture quality — auto-zoom, cursor smoothing, on-screen keystrokes, and a clean padded background — and does not capture microphone or system audio. If your workflow needs internal sound, record it with a loopback tool or add a voiceover and soundtrack in a separate audio or video editor, then pair it with Limelight's polished silent footage. This keeps each tool doing what it does best.