My Windows HTC phone makes a high pitched sound when I receive a call or a calendar reminder.

[Windows Central Question]

The high-pitched noise or squeal occurs when I receive a call, open an email, and receive a calendar reminder. The noise lasts 5-10 seconds and is audible at least 25 feet away (several office cubicles away, for example). I have had the phone approximately one year and this noise started occurring about 3 weeks ago.