Ultrasonic Range Finder: Automatic Volume Control

by wary
(kuala lumpur ,Malaysia)

I want to modify the project from finding the range, so it can control the volume. For example, I make surround sound speaker system.

If the person is near to the speaker, so the volume will decrease. And if the person is far from the speaker, the sound will be louder.

For controlling the volume, I will use DS1669 ic from Dallas technology. Can you give me a suggestion on what can be done?