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."
