Fact sheet
It's a Blast!
Sound Levels and Loudness of Commercials
You're watching your favourite television program. All of a sudden, you're
startled half out of your seat with a blast of commercial message. Or maybe
you've noticed a big difference in the sound level from one TV channel to another
- or even from one TV program to another!
Setting and maintaining sound levels so they are perceived correctly by all
listeners has been a complex process for all concerned for a long time now. And
as the conversion from analog to digital - and to high definition digital – gets
underway, further complications have arisen. We recognize these problems and
together with the broadcasting industry, solutions are being developed.
These issues are difficult to tackle and fix for a number of reasons. To begin
with, loudness is a subjective thing: It depends on the absolute level of the
sound being broadcast and also the nature of the sounds – their density and their
audio surroundings. As a result, there are no commonly accepted standards by
which to judge loudness. However, a few of these technical and psychological
factors identified in a number of studies are outlined below.
As if that weren’t enough, the systems by which TV signals are now distributed
have become much more complex in recent years. For example, signals are often
converted from analog to digital and sometimes back again during their production
and distribution. Furthermore, there are many more steps in a typical
transmission chain from originator to viewer. For this reason, many companies
have begun using equipment which automates the setting of their audio signals.
However, this way of doing things works best when certain system information is
sent and recognized in the same way by all of the different parts of the TV
signal distribution system. Because of the complexity of this system and the wide
variety of “players” sometimes the system does not work as well as it could. But
the industry is working on it.
Recently, Canadian cable companies, satellite signal distributors, TV
stations, specialty and pay-TV services, and program producers, have formed a
working group to address the growing number of customer and viewer complaints
about sound levels. This working group is currently finalizing a system solution
and expects to implement new procedures and guidelines to assist in the alignment
of audio levels by the end of 2005.
While these improvements and adjustments take place, viewers may notice some
temporary variations in the sound levels of certain programs. These adjustments
should take about two to four weeks to complete. And then the audio levels – and
most problems with loudness - should level off!
Technically speaking
"Audio compression" appears to be the most frequent cause of listener
annoyance. It's a technical method by which a commercial's sound track is
recorded at a constant and maximum loudness level. When played within a program
featuring a normal range of sounds – some loud, some soft – the contrast can be
startling. Television and radio stations are in a bind. If they reduce their
volume level to try to minimize the effect of commercials, the range between the
lowest and the highest sound levels in their normal programming would be too
restricted.
Buzzsaw barrage
"Re-shaping the sound" is another commercial production method. The
frequencies your ears are most sensitive to are raised in level, while other
frequencies (those which can make sounds more pleasant to listen to) are reduced.
The resulting commercial now features a sound track that grabs your attention,
but may also sound harsh – especially when combined with the audio compression
technique.
Faulty level
A faulty audio level setting at the local station is a possibility, but most
radio and television stations take care to ensure their programs and commercials
don't exceed the maximum level set by Industry Canada's Broadcasting Regulation
Branch. If you think a faulty level setting is to blame, give the station the
specific date, time of occurrence, and commercial involved. Ask them to check the
audio levels being fed to their transmitter. A Regional or District office of
Industry Canada can also be asked to investigate.
Rude awakening
Even if a commercial doesn't use the audio compression or frequency reshaping
techniques, it could still give the impression of being louder than the program.
Sometimes a commercial intrudes on an otherwise tranquil scene in a program. The
contrast can be startling – even though the commercial is not really excessively
loud.
This document is available in alternative format upon
request.
Date Modified: 2005-12-07 |
