Today, indoor swimming pools are used for more than just recreation. And indoor water parks have gained popularity. Activities such as swimming lessons, kayaking, SCUBA diving instruction and aquatic exercise are scheduled daily. Communication between swimmers, lifeguards and instructors during these activities may be disrupted because of the echo.

Most people have experienced the echo heard in indoor pools. Several aspects of pool designs contribute to the echo: cement, tile, glass and other hard, flat surfaces such as water. In fact, water has been found to be a significant source of echo.