LONDON: British viewers are sensitive to loud TV commercials it seems. So says the Broadcast Committee, a subset of the nation's Committee of Advertising Practice, prompting a new rule that TV ads must not be "excessively noisy or strident".

A sentiment with which fans of fuzzy phraseology will enthusiastically concur. But how do you determine "excessive noise" or "stridency" in ads? Or programs, for that matter?

The CAP/BC acknowledges this to be a problem. Many ads, it says, use a recording technique called audio compression which shrinks the range of sounds in a 30-second spot.

This enables commercials to adhere to previous guidelines that require commercials to be no louder than the maximum volume of surrounding shows.

But this doesn't help much. A movie, for example, might run the full gamut of decibels from a sigh to a volcanic eruption. Which should a broadcaster use as a yardstick?. 

Nothing fazed, the new guidelines take account of this: "Broadcasters must endeavor to minimize the annoyance that perceived imbalances could cause, with the aim that the audience need not adjust the volume of their TV sets during program breaks."

This happy state is achievable via a loudness-level meter, which monitors 'subjective volume' – the audio level perceived by the ear in a show with a range of sounds. CAP/GBC urges use of meters as the best way to handle compressed ads.

CAP's Broadcast Committee is contracted by UK communications regulator Ofcom to construct and police the codes of practice governing TV and radio advertising. 

But the same rigor is rarely applied to excessive noise levels and the Advertising Standards Authority last year received over one hundred complaints from viewers about noisy ads.

Data sourced from New York Times; additional content by WARC staff