Set a Custom Timer Ringtone
If the timer on your Xiaomi phone keeps playing the same generic tone, you probably want something you actually notice - or one you can tune down for lighter naps. MIUI lets you swap the timer sound for a pre-installed ringtone or your own .mp3 file, but the option sits several taps deep inside the Clock app and is easy to miss. Picking the wrong file type can also mean silence instead of a sound.
Change Alarm Volume
If the alarm on your Xiaomi phone barely wakes you up or does not go off loud enough, the alarm volume is set too low system-wide. This one setting controls every alarm you create, and it stays the same even after the snooze function kicks in.
Restrict Floating Notifications in Do Not Disturb
If your Xiaomi phone keeps popping up banners while Do Not Disturb is active, incoming alerts are still showing as floating notifications instead of staying silent. The messages themselves are not lost, they simply arrive quietly in the background, but the pop-ups still interrupt whatever you are doing. This setting decides whether MIUI shows those floating banners while DND is on.