special report loudness control
With broadcast production formats and workflows changing so rapidly, audio teams are continuously presented with new challenges. At virtually any stage of production, from content generation to end-product distribution on a variety of channels, there is a high demand for metering an incredible number of audio formats. These metering processes are often held to an array of new criteria and the result reports must be clear and easy to understand. Due to these new standards, the times when a serial- peak meter inserted into the stereo master bus of the broadcasting desk would provide all necessary information on broadcast audio are definitely over. And while the engineer’s ear definitely plays a key role in evaluating signal quality, it has become less appropriate as the only QA tool in modern environments. Mike Kahsnitz, technical director at RTW, reports.
Loudness control: new challenges for broadcasters
W
hile older metering designs still meet current requirements, it is only on a very limited basis.
Reasons include low channel counts, limited computing power not providing the processing capacities required for more than metering, and user interfaces that are outdated compared to modern workflows. For these reasons and more, a shift has begun from peak to loudness metering, which the broadcast industry is currently undergoing. Loudness metering is an essential component of a fully integrated loudness- management system as specified by current standards and recommendations including EBU R128, ITU 1770/1771, ATSC A/85, the CALM Act or ARIB. As standard computers are
becoming more and more powerful, the obvious question in connection with increased metering demands is whether using a software application running on a standard PC would not be a simpler approach compared to dedicated hardware solutions. In this case, however, the solution providers
Practically all major broadcasting services worldwide are currently thinking about using loudness meters rather than peak meters for controlling signal levels or have already completed the change.
would not be able to control critical parameters including the graphics resolution, the display device and the audio interface since choosing the respective hardware components would be up to the end user. Therefore, when using a pure software solution, controlling crucial display settings such as the time response would be impossible. In addition, the majority of professional broadcast engineers are convinced that meters should be permanently visible. The metering instrument should neither depend on launching a specific software application, nor should it be possible that the metering window is hidden behind another window on the computer screen. Hence, an autonomous and permanently available meter is still the instrument of choice in the vast majority of professional broadcast scenarios. For decades, RTW has specialised in
visualising audio and now offers an entirely new metering product based on the above considerations: the TouchMonitor range. The TouchMonitor combines the technological benefits of a dedicated hardware with the flexibility of software solutions and a highly ergonomic touch-sensitive
78 l ibe l september/october 2011 l
www.ibeweb.com
display. The first two models of the new range - the TM7 with a 7" display and the TM9 featuring a 9" display - integrate the entire signal-processing functionality, the display unit, and all interface ports into a handy hardware unit with an overall depth of just 46mm. Thanks to the amazing power of modern DSP technology, a TouchMonitor simultaneously visualises up to 16 signal sources using many flexible and highly advanced instruments. The 3G SDI interface for the larger TM9 model, which will be launched this summer, is capable of processing and visualising up to 32 input signals at the same time. In addition, the unit handles and displays many independent audio groups simultaneously within the same preset. Each group is displayed on a different instrument. While the screen layout of traditional
RTW meters was largely static, the TouchMonitor allows for freely arranging, scaling and (where appropriate) even rotating all instruments that are part of a preset on the screen. Thus, the user can quickly access a large number of signal paths, each configured with the appropriate instruments, using presets.
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