All broadcasters implemented and enforced stricter audio standards from January 2013. These standards were improved further in January 2014 to align them with an improved Australian standard called Operational Practice 59 (or OP-59).
OP-59 is based on the perceived loudness of the soundtrack in contrast with the earlier standard (aligned with Australia’s OP-48) which was based on the electrical level of the audio signal. The purpose of OP-59 is to further reduce the number of complaints about jumps in audio levels between advertisements and programs.
For technical specifications relating to this click here.