Take a look what i just found at amazon:
Their description:
Product Description
Automatically Adjusts Volume for Normal Listening Levels / Compatible with any Television using RCA Composite Connectors. Do you find your self repeatedly adjusting the volume on your TV and home-theater sound system? TERK VR-1 Volume Regulator is a fully automatic device that automatically adjusts loudness to proper listening levels. Also works with MP3 play through audio and computer systems 3.8 High x 3.2 Wide x 1.4 Deep… More >>
Go & get it here - i can recommend it:
Terk VR1 Automatic TV Volume Controller