The Broadcast Committee of Advertising Practice (BCAP) has launched a consultation on the sound levels of TV ads. Its consultation paper includes a proposal for a new rule that would provide more certainty for broadcasters and ensure that no single ad in a commercial break is significantly louder than the others.
Between September 2005 and December 2006, the Advertising Standards Authority received 245 complaints about the perceived noisiness of TV ads.
The existing rule states:
Advertisements must not be excessively noisy or strident. Studio transmission power must not be increased from normal levels during advertising.
Note: The peak level of sound at the studio output should not exceed +8dBm. To ensure that the subjective volume is consistent with adjacent programming, whilst also preventing excessive loudness changes, highly compressed commercials should be limited to a Normal Peak of 4 and a Full Range of 2–4 (measured on a PPM Type IIa, specified in BS6840: Part 10, Programme Level Meters). A fairly constant average level of sound energy should be maintained in transitions from programmes to advertising breaks and vice versa so that listeners do not need to adjust the volume. A perceived loudness meter may be useful where sound levels might cause problems.
According to BCAP, the note to the existing rule is difficult to interpret. Audio compression takes place when minimum sound levels are raised artificially during the production stage in order to make them stand out; but the note does not explain what constitutes a "highly compressed" advertisement. That allows broadcasters to transmit compressed ads and decide for themselves what a suitable peak level would be, up to +8dBm.
Even at lower levels, an ad can sound excessively noisy if the TV programme content is quiet. A channel showing old movies "would likely have a quieter loudness profile than a music video channel or a sports channel," explains the BCAP document.
The proposed replacement rule states:
A consistent subjective loudness must be maintained between individual advertisements and between the advertisements and programme and other junction material. Measurement and balancing of subjective loudness levels should preferably be carried out using a loudness-level meter conforming to ITU recommendations. If a peak-reading meter is used instead, the maximum level of the advertisements must be limited to 6dB less than the maximum level of the programmes to take account of the limited dynamic range exhibited by most advertisements.
For editorial reasons, commercial breaks sometimes occur during especially quiet parts of a programme, with the result that advertisements at ‘normally acceptable’ levels seem loud in comparison. Broadcasters must strive to minimise the annoyance that that perceived imbalance could cause the audience, with the aim that the audience need not adjust the volume of their television sets during programme breaks.
BCAP anticipates that the new rule will "reduce the risk of the audience having to adjust the volume in the advertisement breaks because they consider the advertisements to be too loud."