Broadcasting Framework LO 10

The audio industry has many different standards for different things. However Broadcasting is the most documented and most common of audio standards in the world, with different countries using different standards with different laws governing what they can and can’t do. There is a real need at the moment for one governing standard to combat varying degrees of volume in broadcasting be it TV, Radio or some other form of broadcasting.

From the very beginning of Digital audio sample peak metering has been used to determine the level of audio tracks. Some companies are able to fool this method and make their audio more attention grabbing than their competitors but in turn makes listening to different broadcasts sometimes very dismaying. Heavy use of compression and limiting are the way around this method and it makes the audio inconsistent and reduces the quality of the audio in a very dramatic way.

Now though we have different standards across the world to measure loudness in broadcasts. They all have different names but they achieve the same goal in measuring loudness in broadcasting for example:

  • 1 unit of LKFS (Loudness K-weighted Full Scale) = 1dB (US)
  • 1 unit of LUFS (Loudness Units Full Scale) = 1dB (EU)
  • 1 unit of LU (Loudness Units) = 1dB (International)

LKFS and LUFS are based of the international ITU BS.1700 standard. With -25 LKFS and -23 LUFS being the limit for the U.S and Europe they are both equal to 0 LU

However in 2006 the International Telecommunication Union released the ITU BS.1770 which is a uniform standard for measuring perceived loudness uses a algorithm that can measure a humans perceived loudness, by using this algorithm you can get a quantitive measure of the loudness of a track. Many countries broadcasting standards are based of this standard such as Australia’s OP59 standard.

OP59 was brought out in January 2013 in a effort to bring Australia and New Zealand in line with the same standards as other countries such as the U.S and Europe.  Previously metering was done using a VU meter which only measures signal level with the OP48 standard which wasn’t very definitive in the face that you could put a multi-band compressor on the track and make the audio seem louder while still falling in line with the OP48 standard. This is why there have been many complaints in different audio jumping in volume with the old standard. But with the new OP59 standard being based on the ITU BS.1770 standard there is no way around the standard resulting in seamless loudness in audio in broadcasting.

However when talking about music in broadcasting different genres sound different in terms of loudness. For example Classical Music sounds very different to Metal. Gates are used in broadcasting to combat this it brings them to the same level making it more genre friendly. Holding the level for louder music at -10 LUFS.

All of these standards and ways of measuring loudness internationally they all want to achieve the same goal of making consistent audio levels in broadcasting.

References:  

http://www.tcelectronic.com/loudness/loudness-explained/

http://www.sandymilne.com/op-59-and-loudness-standards-for-australian-tv/

http://www.tcelectronic.com/loudness/broadcast-standards/

http://www.freetv.com.au/media/Engineering/OP59_Measurement_and_management_of_Loudness_in_Soundtracks_for_Television_Broadcasting_-_Issue_1_-_July_2010.pdf

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