The main reasons why alarms can be so quiet include low system or alarm volume settings, certain features that reduce alarm sound when the phone detects you're looking at it, and the selected alarm sound itself possibly being inherently quiet. For iPhones specifically:

• The alarm volume is tied to the "Ringtone and Alerts" volume slider in Settings > Sounds & Haptics. If this is set low, alarms will be quiet. Also, if the "Change with Buttons" toggle is on, volume buttons might have accidentally lowered the alarm volume. Increasing this slider and turning off "Change with Buttons" can help.

• The selected alarm sound might be quiet by nature or set to "none". Changing to a louder or more distinct sound in the Clock app helps improve alarm volume.

• An iPhone feature called "Attention Aware Features" (in Settings > Face ID & Passcode) can lower alarm volume when it detects your gaze. Disabling this feature has helped some users restore alarm volume.

• Other focus or sleep settings may influence alarms as well, so those should be checked if alarms remain quiet.

In general for any phone:

• Ensure the system volume is turned up.
• Verify alarm sound settings.
• Disable smart features that reduce volume based on context or gaze.
• Consider restarting the device or checking for bugs if issues persist.

This comprehensive check should help diagnose and fix the issue of quiet alarms effectively.