Starting in September German TV viewers won't have to put up with disproportionately loud commercials, trailers, or pop music interludes. A new volume standard could lead to more dynamic sound quality.
It has happened to everyone - when watching the news or listening to some quiet music on the radio when an advertising block starts by blaring music that overwhelms every other sound in the room. Until now, Germans - like everyone else - were left searching for the remote control to quickly turn down the volume.
But the new R128 loudness standard, which is endorsed by the European Broadcasting Union, came into effect September 1. The rule is simple - a program's audio level must remain within the bounds of a well-defined framework. But that hasn't stopped the advertising industry from getting sounds across at the levels it wants in commercials.
Analyzing the peaks
When measuring sound on a wave form, loud commercials technically have the same level as quiet sounding voice contributions. A pop song reaches the same peak levels as a relaxed jazz interpretation. That one is clearly louder than the other is due to a trick used by producers called compression.
"It ensures that the quietist places are as loud as possible within a program, and the loudest places remain as loud as they are," said Jörg Morawetz, a DW sound engineer. "The quiet parts in a program are brought up closer to the loud parts.”
Advertisers use compression so listeners can still hear commercials even if they leave the room. But it is not an enjoyable listening experience because it alters the so-called dynamics of the sound signal. Instead of experiencing the full range between the softest and loudest sounds, when using dynamics a whisper can sound just like the bang of a drum.
Dynamics mean range
Loud and condensed audio may seem brisk and probably drives blood pressure up, but it isn't loud in an acoustic sense.
"During a nice program it seems very quiet at times or even very loud," said Morawetz.
Dynamics are desired because they create versatility and variety. The greater the dynamics the better and audio track sounds to the human ear. But when compressed advertising roars out of the TV screen the listening pleasure is over.
Now instead of measuring sound by peak levels on a wave form, the new law calls for sound to be measured by it loudness. A new unit called a Loudness Unit (LU) will be used for measurement. An LU is the same decibel level that was valid before but with one crucial difference - the loudness measurement samples the level over a much longer period of time.
"Up till now signals with a time interval of 10 milliseconds have been involved in the measurement," said Morawetz, who was responsible for the loudness project at Deutsche Welle. "That took into account very short peaks in the audio signal that pushed up the measuring instrument's level even though the peaks are sometimes so short that a person listening cannot hear the sound."
Instead of a 10-millisecond interval, the new rule calls for a 400-millisecond interval.
"That is almost half a second and as a result this measurement method conforms closer to the way people hear," Morawetz said.
Hoping for a better sound
Initially the goal was to tone down loud, compressed audio. Over the medium-term, the new rules could develop to be even more effective. "One would hope that, in the future, advertising producers will have more dynamics in their programs," said the engineer.
Soon commercials will not only sound less loud, but may even become pleasant to listen to - at least as far as the technical acoustics are concerned.