I have an iPod touch (4th gen). A few weeks ago, it started making an alert sound (tritone) every day at exactly 12 noon. There is no on-screen alert, nothing in the Notification Center pull-down. Just a sound. Every day.
I have NO apps in my Notifications (Settings). I have NO alarms set. NO reoccurring calendar items.
Anyone have a clue why my device is doing this?
