mediteo uses a short and discreet sound for all reminders. However, you can customize this.

Changing the volume:

The volume is not managed by mediteo, but by your smartphone.
So make sure not to turn off the sound on your smartphone or set your smartphone to silent or do-not-disturb mode.

Enabling/disabling certain notifications:

iOS:

More → Settings → Reminders → Notification sound on/off

Android:

More → Settings → Reminders → Notifications → Adjust → Activate/deactivate reminders

Change notification sound:

iOS:

More → Settings → Reminders → Sound → Select new sound

Android:

More → Settings → Reminders → Notifications → Adjust → Select Reminder Type → Sound