Hello berryi, and welcome to the Apple Support Community.
Since the sound only happens after waking your MacBook Air from sleep and not after a normal startup, try these steps:
- Restart your Mac and make sure macOS is updated to the latest available version.
- Disconnect any external accessories and check if the sound still happens after waking from sleep.
- Start your Mac in safe mode to see if the issue continues. This can help check whether software loading in the background is causing the behavior.
- Check System Settings > Notifications and System Settings > Sound to see if an app or alert sound may be triggering after wake.
Since your MacBook Air is new, if the sound continues after these checks, contacting Apple Support would be the next recommended step.
Useful links:
Start up your Mac in safe mode - Apple Support
Use Apple Diagnostics to test your Mac - Apple Support
Take a screenshot on Mac - Apple Support
Please let us know if these steps identify what is causing the sound after waking from sleep.
Your feedback may help other Apple Support Community users with a similar question.
🙏🏻
Have a nice day.
And one more thing…
Never forget to think different.
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