MacBook Air CRACKLING RIGHT SPEAKER.

Hello blowlory99,

Based off of the information you linked in your post, the right speaker on your MacBook Air pro produces a crackling sound when playing high-pitched sounds. Also, your Mac was recently replaced for this same issue. I'm happy to help you get to the bottom of this.

While it is possible this is a hardware issue, there are some steps you can take to make sure. Try these out:

1. Update your Mac computer to the most current version available for it: How to update the software on your Mac.
2. Make sure the Balance slider for your output sound is in the middle in System Preferences > Sounds > Output.
3. Test out the sound while there are no peripherals and accessories connected to your Mac other than the power cable.
4. Reset the NVRAM: Reset NVRAM or PRAM on your Mac.
5. Test the sound while booted in safe mode: Use safe mode to isolate issues with your Mac.

Thanks for using Apple Support Communities.

Take care.

Hello again blowlory99,

Thanks for responding back to let us know you're still experiencing the same thing.

Next you can try testing out your speakers while booted into a brand-new user account: How to test an issue in another user account on your Mac. This helps narrow things down even further. Reinstalling macOS would be the last step to try and narrow things down to being hardware or software related: How to reinstall macOS from macOS Recovery.

If you continue to experience the same issue I recommend reaching out to Apple Support: Contact Apple for support and services.

Thanks for using Apple Support Communities.

Take care.