TV Advertising Sound Levels 

Since assuming responsibility for TV advertising regulation, the ASA has received hundreds of complaints from viewers objecting to what they have found to be “noisy ads”. In many of those instances, the ASA has found that the ads have been broadcast at levels that are acceptable according to the current stipulations of the BCAP TV Advertising Standards Code. Concerned at the apparent incongruity between viewer perception and the realities of TV ad broadcasting, BCAP has been monitoring the ad sound levels issue and now proposes that the current rule on sound levels be changed. But what does it all mean for the viewer?

Sound level standards – the technicalities (you may wish to skip to the next section!)
Sound levels in TV broadcasting have traditionally been measured using Peak Programme Meters (PPMs), which indicate the peak sound levels (the loudest part or parts) of ads’ soundtracks. Currently, the BCAP TV Advertising Standards Code states that: “ads must not be excessively noisy or strident. Studio transmission power must not be increased from normal levels during advertising.”
 

A peak programme meter

To comply with the rule, broadcasters are told that the peak sound level at the studio output should not exceed a level of 6 on the PPM or, as a lot of advertisers today use sound compression techniques, a maximum level of 4 on the PPM is imposed on ads with a highly compressed soundtrack. Compressing an ad’s soundtrack is akin to levelling out the ‘peaks and troughs’ of the sound waves so that the peak levels of the compressed version would be the same as those of the “natural” version but the ‘troughs’ are raised. The graphs below illustrate the difference between natural and compressed sound waves.   

     
                      Natural sound                                         Compressed sound

The overall effect will be that the ad is subjectively louder. Also an ad break may occur during a quiet moment in a programme, therefore increasing the perceived loudness of the ads that follow.

What is to be done?
BCAP’s proposed rule encourages broadcasters to measure the subjective loudness levels of ads, rather than simply measuring peak sound levels. Subjective loudness is based on:

*the peak levels of sounds
*the length of time sound levels are maintained
*the different frequencies, or ‘pitches’, contained in the soundtrack.

Under the proposed rule, broadcasters will be told that “A consistent subjective loudness must be maintained between individual advertisements and between the advertisements and programme and other junction material.” 

The proposed new rule gives broadcasters much more technical guidance on how they can ensure greater consistency between ad and programme sound levels. The International Telecommunications Union (ITU) has drawn up recommendations on measuring subjective loudness levels; those recommendations have been incorporated into the proposed rule. Broadcasters will now have the option to carry out their testing in accordance with the following ITU recommendations:

Algorithms to measure audio programme loudness and true-peak audio level (ITU-R BS1770)

and

Requirements for loudness and true-peak indicating meter (ITU-R BS1771)

What should it all mean?
If the proposal is accepted, BCAP considers that broadcasters should be better able to match the sound levels of ads with the sound output of the whole channel. That means there should be less of a perceived imbalance between ad and programme sound levels, leading to less viewer irritation and fewer complaints to the ASA.

What now?
BCAP is consulting on its proposed rule. The purpose of the consultation is not simply to ask if TV ads are too loud: BCAP already acknowledges that some viewers perceive that they are. Instead, the purpose of the consultation is to encourage technically informed responses as to whether the proposed rule will give broadcasters enough guidance to ensure that there will be less of a perceived disparity between the sound levels of TV ads and programmes.

The consultation will close on Friday 17 August 2007 at 5pm. Any responses received will be considered and then a final decision made. BCAP will announce its decision later in the year.

Further information on the consultation can be here.