To put an end to the annoying variations in sound volume between programs and advertising breaks, the International Telecommunications Union (ITU) is about to adopt a new standard on audio levels for broadcast television.

The UN-affiliated body said it is recommending the new standard because many viewers get irritated when changing channels or when a commercial break leads to a significant variation in the audio levels accompanying the picture.

“Viewers generally adjust the sound to their liking when they settle down to watch their program, only to find that changing channels or interrupting the program for an advertising break requires them to adjust the volume control all over again,” the ITU said.

The ITU explained that the proposed new measuring technique will bring more uniformity to loudness in international program exchange and make television viewing more pleasurable.

“Loudness variation has become more noticeable with the advent of digital broadcasting because of higher sound quality, so this development is expected to be eagerly received by industry and viewers alike,” it said.

The ITU said viewers often erroneously blame differences in loudness on careless sound technicians or deliberate policies on the part of broadcasters and advertisers. But the fact is, the agency said, there are a number of technical reasons for differences in “loudness” which are not currently easily controlled at the broadcast studio.

When sound is measured on a technician’s VU (volume unit) meter, the equipment registers the strength of the electrical sound signal, which is not itself a direct measure of how loud the TV sound will be to viewers, the ITU said. Volume is also affected, it added, by other things such as the range (or degree of compression) of the sound.

To rectify the problem, the ITU said broadcasters need a monitor or meter which displays “loudness” (rather than electrical signal strength), and an agreement on a standard setting level for loudness, so that sound technicians everywhere can make the same adjustment.

The new ITU recommendation suggests how sound levels should be measured and set in international program exchange to maintain more constant volume for viewers.

The draft will now be submitted to national telecommunications administrations for approval, the ITU said.(Edwin P. Sallan)