Hold Option and click the speaker icon in the menu bar to see all available output devices — select the one you want. Alternatively, go to System Settings > Sound > Output and choose your device. For Bluetooth headphones, connect them first, then select them from the output list. If a device doesn't appear, disconnect and reconnect it. Mac defaults to the last-connected device (e.g., plugging in headphones auto-switches from speakers). To switch audio for a specific app (like routing Zoom to headphones but music to speakers), you'll need a third-party app like SoundSource or Audio Hijack, since macOS doesn't natively support per-app audio routing. For HDMI/DisplayPort audio, select the display from the output list. If sound plays through the wrong device after waking from sleep, re-select your preferred output.
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