Fact sheet
It's a Blast!
Sound Levels and Loudness of Commercials
Introduction
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!
Loudness variations between ads and programs or between programs account for a number of viewer complaints. But why does it happen and what can be done?
Why sound levels vary
The causes of loudness variation can be any of the following:
- Ad production techniques
- Contrasting sounds
- The TV transmission process
Ad production techniques
Audio compression is a recording technique in 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.
"Re-shaping the sound" is another commercial production method. Those frequencies to which the ear is most sensitive are raised in level, while frequencies that make for more pleasant listening are reduced. The resulting commercial now features a sound track that grabs your attention, but which may also sound harsh – especially when combined with the audio compression technique.
Contrasting sounds
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.
The TV transmission process
The process of moving pictures and sound from production studios to your TV is a complex process with many intermediate steps involved. These video and sound elements are handled by producers, engineers, editors, archivists and others, combined and fed to transmission devices which in turn deliver the signal to over-the-air or via cable, satellite or other distribution technologies to your home receiver – the TV set.
Transmissions also involve many kinds of material such as new programs and ads, archival material, live and taped broadcasts, as well as combinations of technologies such as programs and ads recorded with analog technology and delivered via analog, programs and ads recorded with analog technology and delivered by digital means, or programs and ads produced and delivered digitally.
Fixing the problem
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 group worked throughout 2005 to finalize a system solution and to implement new procedures and guidelines to assist in the alignment of audio levels. While these improvements and adjustments were being made, viewers may have noticed some temporary variations in the sound levels of certain programs.
It’s an ongoing process and it will take some time to get programming sound levels in order. There will also be exceptions -- as older broadcasts were never produced with target audio levels in mind, they cannot be expected to meet the target ranges agreed by the working group. Quality control and verification by individual programming services are the keys to success.
What you can do
Ongoing difficulties with audio levels should be reported to the programming service involved, as well to company who delivers the signal to your home. Ask the programming service to check the audio levels being fed to its transmitter, taking care to note the specific date and time of occurrence and the program or commercial involved.
This document is available in alternative format upon request.
Date Modified: 2006-09-06 |
