Apple MacBook Air 15-inch (M3) has no sound or distorted audio

The checks in more detail

A monitor connected over HDMI or Thunderbolt often becomes the default output without telling you, and a monitor with weak or no speakers leaves the Mac seeming silent. AirPods and other Bluetooth devices reconnect automatically when nearby, so a pair in a bag in the next room can take the sound. Spatial Audio and Dolby effects change how it sounds; test with a stereo song with Spatial Audio off. If the sound crackles, close apps that use audio heavily, such as video editors or conferencing apps, and restart; a stuck audio process is cleared by restarting the Mac.

Check the volume of the app itself, since some apps have their own volume slider, and the alert volume under Sound Effects. If you use an aggregate device or a virtual audio driver from a screen-recording tool, remove it, because virtual drivers sometimes take over the output. Keep keyboard covers and sticky film off the grille above the keyboard, which muffle the speakers. If no output devices appear at all, or the speakers are silent with MacBook Air Speakers selected and every setting right, the problem may be hardware and Apple Support should run diagnostics.

Water or a drop can damage the woofers. Update macOS, as sound fixes arrive with updates. If you use the Mac for music, check Music app's Equaliser and Sound Enhancer settings, which color the sound, and macOS's own Audio MIDI Setup to see the format of the output, since a sample rate set oddly can cause crackle. Apple's built-in Spatial Audio for the Air's speakers is optional, and on some content it makes dialogue less clear, so toggle it in the sound menu when you play video and compare.