Loud Commercials and the CALM Act
Effective December 13, 2012, the FCC's rules require television commercial advertisements to have the same average volume as the programs that they accompany. The FCC established these rules to comply with the directive of Congress contained in the Commercial Advertisement Loudness Mitigation (CALM) Act (PDF).
What the New FCC Rules Do
The FCC's new rules require TV stations, cable operators, satellite TV operators and other pay TV providers to limit a commercial's average volume to that of the programming that it accompanies. A commercial may have louder and quieter moments, but, overall, it should be no louder than the surrounding programming. This may mean, however, that some commercials will comply with the new rules, but still sound "too loud" to some viewers.
http://www.fcc.gov/guides/program-ba...ud-commercials