June 5, 2008
As an avid audio / video enthusiast, my friends and family will often contact me when they have a question about their home AV system. One of the most common questions I get, is regarding the relative inconsistency in audio level between different TV programs, channels and in particular commercials. The complaint about TV commercials has been around for a long time, but with the advent of HDTV and digital broadcast television, new technologies are available to the content creators and broadcasters which are designed to mitigate the severity of these differences in level. Unfortunately, even with HDTV and digital broadcast television, the problem hasn’t improved much and in some cases it seems to have gotten worse.
The reasons for the lack of improvement are complex and often vary depending on the content creator, broadcast network and even differences between national and local broadcast networks. To help understand what is causing these ‘issues’, it is probably best to first review one of the key technologies that is available today, to help mitigate this problem. Dolby Digital, which is currently used as the preferred audio delivery format for many HDTV broadcasts, includes several unique features which are designed to help improve consistency between various broadcasts and other audio sources.