System audio vs microphone
System audio is the sound produced by macOS and its apps. The microphone records your voice and surroundings. A narrated tutorial may use both; a silent product demo may only need internal audio.
Check macOS privacy permissions
Open System Settings and go to Privacy & Security. Allow Frame Record under Screen & System Audio Recording. Enable Microphone access when needed, then relaunch the app if macOS requests it.
Get clean audio levels
Lower notification volume, keep the microphone at a stable distance and avoid clipping. Headphones prevent the microphone from capturing speaker output. Always record and review a short test.
Use pause during capture
Pause lets you interrupt an explanation without creating multiple files. Paused time should not appear in the final recording. Resume only when the window and audio sources are ready.
Review the exported file
Listen to the beginning, a transition and the ending. Check synchronization between cursor, video and sound. For important publishing work, review with headphones and on a second device.