Apple Watch Series 7 speaker or microphone is muffled

The checks in more detail

Water-resistant does not mean the openings stay clear: after swimming or a shower, water can sit in the speaker and muffle it. Apple's Water Lock, which you turn on from Control Center, uses sound to push water out of the speaker; turn it on, turn the crown to eject, and the watch plays a tone. Do it after any swim, then test the speaker. Clean the openings gently. Rinse the watch under fresh water if it has been in soapy or salty water, dry it with a soft lint-free cloth and leave it for a while.

Do not blow compressed air into the openings or use a sharp object, which can damage the meshes and the seals. Take the watch out of its band and case and look for a film. Check the settings: in Settings, Sounds and Haptics on the watch, check the volume and that Silent Mode is off, and in the Watch app on the iPhone check the same. For calls, check the audio route: the watch uses its speaker only when the call is on the watch, so a call routed to the iPhone or to a Bluetooth headset sounds different.

Make sure the watch is connected to the iPhone, and restart both. Software also matters. Update watchOS through the Watch app on the iPhone, with the watch on its charger. If the problem is only on certain apps, check their settings and microphone permission. Restart the watch by holding the side button and sliding the power off slider. If the sound stays poor after drying and cleaning, the speaker or microphone may be damaged, and Apple can test them, so contact Apple Support with the serial number. Avoid exposing the watch to soaps and hot water, and rinse after salt water.