iPhone ringtone gets quieter when you look at it: check Attention Aware

Notice whether the alert starts at a normal volume and becomes quieter as you look at the phone. That pattern makes Attention Aware Features worth checking. Apple documents attention-based alert reduction on supported TrueDepth devices even when Face ID has not been enrolled. An iPhone SE does not have the same TrueDepth support.

Open Settings > Face ID & Passcode and switch off Attention Aware Features. Ask someone to call again and compare the behavior from the same position. This switch also affects other attention-based behavior, such as keeping the display from dimming while you look at it. Restore it if you prefer those features. Change the named Attention Aware Features switch; the Face ID attention requirement is a different control.

Open Settings > Sounds & Haptics and adjust the ringtone volume slider shown on your iOS version. Preview a ringtone there. Check Change with Buttons: turn it off if you want to prevent the volume buttons from altering the ringer level. A media player’s volume setting is not a reliable way to check the saved ringtone level.

If the ringtone is still faint with Attention Aware Features off, compare its preview with another ringtone at a comfortable setting. Record whether other sounds are also quiet and whether the issue happens for every caller. Give that pattern and your iPhone model to Apple Support if it persists. If no incoming alert starts at all, investigate call delivery or silence settings separately.