The Audio Interruption
macOS uses a feature known as audio ducking to manage competing sounds on your system. By default, when you are listening to Apple Music, Spotify, or a podcast and a system notification arrives (such as an iMessage, a calendar alert, or an email), the operating system automatically lowers the volume of your music, plays the “ding” sound of the notification, and then slowly ramps your music volume back up. While this ensures you never miss a critical alert, it completely ruins the listening experience if you are wearing headphones and trying to focus on an album, as the constant dipping and pausing of the audio track is incredibly jarring.
Isolating the Audio Channels
To stop macOS from ducking your music, you must separate the notification audio channel from your primary media channel. This is done by routing alert sounds to a different device or disabling the audio feedback for notifications entirely.
Open the System Settings app and navigate to the Sound menu in the left-hand sidebar. In the main pane, locate the section titled “Output & Input.” Look below this for a dropdown menu labelled Play sound effects through. If you have an external monitor with speakers or a Mac mini with an internal speaker, change this dropdown from your primary headphones to that secondary device. If you only have one audio output, scroll down to the “Sound Effects” section and turn Off the toggle switch for Play user interface sound effects. macOS will now deliver visual notifications silently, completely ignoring your active music stream and allowing it to play uninterrupted.