This second part of our CALM Act tutorial addresses implementation. The law goes into effect on Dec. 13, and every broadcast engineer should be familiar with the law, its implementation and implications. However, the fact is that much of the law was implemented 17 years ago when the FCC adopted the ATSC standard, including A/52 and A/53. A/52 describes the audio codec, and A/53 describes the DTV format. Both identify the golden rule of loudness, which is that the loudness of normal spoken dialog and the metadata parameter called dialnorm shall match. If all content obeys this rule, the loudness will be consistent.
The CALM Act was passed to eliminate letters, phone calls and e-mails to the FCC or other federal government officials, elected or appointed, complaining about loud commercials. If no viewers complain about loud commercials on your station, then your station is in compliance. However, once the FCC identifies a “pattern or trend” of loud commercial complaints on your channel, be prepared to defend your station with documentation, because documentation is all you’ve got to prove your Innocence.
The great side benefit of the CALM Act is that it opens the possibility for less processing and better dynamic range, presenting the sound track as the content producer intended it to be heard. On the other hand, footnote 119 on page 18 of the FCC Report and Order says not necessarily.
It says, “A station or MVPD can install, utilize and maintain, in a commercially reasonable manner, a real-time or ‘conventional’ processor to ensure consistent loudness by limiting dynamic range, rather than by setting the dialnorm or meeting the Target Loudness. Conventional processing modifies the dynamic range of the decoded content by reducing the level of very loud portions of the content to avoid annoying the viewer and by raising the level of very quiet portions of the content so that they are better adapted to the listening environment.”
In other words, if traditional limiting and compression works for you, fine. Is it the best you can do? No.