In the US, broadcast loudness control became a legal requirement in December 2010 when President Obama signed into law the Commercial Advertisement Loudness Mitigation (Calm) Act. This makes it illegal for commercials to be overly loud compared to the rest of the programming on a given channel. The Calm Act, which refers directly to ATSC Recommended Practice A/85 ‘Techniques for Establishing and Maintaining Audio Loudness for Digital Television’, compels the FCC to enforce rules that ensure that the average integrated loudness of the station audio matches the dialnorm metadata parameter in their transmitted Dolby Digital (AC-3) stream.
In Europe, Loudness recommendations include the ITU BS 1770/1771 specifications that were introduced in 2006, and the EBU R128 recommendation, which was announced at the IBC Convention in September, 2010.
Legislation and control
EBU R128 explains how broadcasters can now measure and normalise audio using Loudness meters instead of peak meters (PPMs), which had previously been common practice. The result of two years of intense deliberation by audio experts in the EBU PLOUD Group, R128 and the four technical documents that support it, build on the foundation of the ITU specifications but add a number of new developments, including a gating method.
R128, which specifies programme loudness normalisation and permitted maximum level of audio signals, is designed to be short, precise, and simple. Basically EBU R128 recommends that broadcasters normalize audio at -23 LUFS ±1 LU, measured with a relative gate at -8 LU.
Jünger Audio’s flagship T*AP TV Audio Processor was launched in 2010 for controlling broadcast audio loudness. The unit, which is fully compliant with ATSC A/85, ITU and EBU R128 recommendations, incorporates a new Sharc-based DSP solution that allows for very precise audio analysis. ‘This unit provides engineers with the perfect solution for controlling audio loudness,’ says Jünger Audio MD, Peter Poers. ‘It takes the broadcaster from postproduction to transmission without encountering any problems from legislators – or any complaints from viewers.’
Jünger Audio’s T*AP is a wideband, eight-channel processor (8x1, 4x2, or 6+2) that focuses on automatic and adaptive loudness control using the company’s Level Magic algorithm. Using proprietary Spectral Signature technology, it also offers dynamic equalisation so that the sound can be ‘coloured’ much more easily than with a traditional multi-band sound processor. Optional Dolby Decoding and Encoding (D, D+, or Pulse), as well as metadata management, are also provided along with 5.1 Downmix and Jünger Audio’s 5.1 UPMIX circuit, which has been upgraded to deliver greatly improved performance and a range of new settings.
The new processor is capable of handling digital inputs (AES) and, through interface slots, all other usual audio formats including all SDI versions (SD, HD, 3G. It is controllable through front panel and Web based GUI, plus remote control, and GPI – and it comes with a redundant power supply as standard. ‘All of our Level Magic based loudness control solutions, including the D06, B46 and C8000 series of products, are already compliant with ATSC and ITU recommendations,’ Poers adds. ‘It is anticipated that the ITU mode will soon be modified to bring it in line with the EBU’s R128 recommendation. We believe this will happen during 2011 and when it does, we will be offering existing Level Magic customers a hardware upgrade programme incorporating the new powerful DSP solution.’
More: www.junger-audio.com
