Front Air speaker problem

If you're talking about the earpiece, and if you're sure that you've already checked that the sound balnace in Settings>Accessibility>Audio/Visual is in the middle, and if you already tried (to no avail) to restart the device after gently cleaning the earpiece (using a strong flashlight, a wooden toothpick, a soft brush, and a bit of patience), I suggest that you contact Apple support directly using this link:--> Contact Apple for support and service , or make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> https://locate.apple.com/choose-country-region . After checking it out, they'll give you all the available options.

Regards

Giulio

(*) You can do it:

• Online:--> Genius Bar Reservation and Apple Support Options - Apple;
• Contacting a local Apple Store or AASP among the list provided above;
• Using the "Apple Store" app, available and downloadable from AppStore.