The View From 2009: This article came about as a follow-up to the one on unintended consequences that was published in May of 2002. Here Dolby has a chance to air their side of the story. For me, it was an interesting introduction to a remarkable company that I have grown to greatly respect over the intervening years. [Some links in the article have been updated. - WebEd.]

Dolby C: How Dolby Sees It

Our Story to Date

Alert readers will recall that I’ve been ranting about “bad audio” for a number of months, and that in my last outing I took on some of the unintended consequences arising from the long-term use of Beta SP and Dolby C in combination. Specifically, I looked pretty hard at Dolby C, as a number of readers have written in to suggest that it is a major contributor to the “bad audio” problems that plague broadcast TV.

Naturally, Dolby has some opinions on the subject, and wanted to have a say about their view of the whole problem. I promised to devote a column to this, and so, after an interview with Dolby’s Adam Anderson and Jim Hilson, here is Dolby’s take on the issue.

Adam Anderson and Jim Hilson

Adam Anderson is Public Relations Coordinator and Jim Hilson is a Senior Broadcast Audio Specialist for Dolby Labs. I’ve known Jim through various audio conferences and panels for a number of years, and consider him both knowledgeable and highly competent. I’ve had no prior experience with Adam, but for this process I found him very helpful, professional and reliable.

The Noise Reduction Wars: Some History

Dolby A came on the scene around 1967, followed a year or so later by Dolby B. Dolby A is a professional noise-reduction system that utilizes four separate bands of companding. Dolby B is a consumer equipment system that uses one band of companding, concentrating on high frequencies. Dolby A yields about 14 dB of noise reduction and Dolby B yields about 10 dB. Keep in mind that those noise reduction numbers are simplifications of what is REALLY going on, but they are the primary numbers used to describe noise reduction performance by marketing departments (you might want to read the section on “The Meaning of Specs” in my book Total Recording for more information on this).

Dolby was successful with these systems, and so, competition sprang up, most notably dbx, which was introduced around 1972. Dbx used a different approach to companding than either Dolby A or Dolby B, and naturally there were many arguments about the relative quality of each system. Without getting into it, note that dbx claimed 20 dB of noise reduction, which naturally appeared to significantly outperform either Dolby A or B. For a variety of reasons, Dolby chose not to modify Dolby A, but around 1980 they did create a new system called Dolby C, which was in many respects equivalent to a pair of Dolby B circuits in series. Interestingly, and not coincidentally, Dolby C was advertised as yielding 20 dB of noise reduction.

Such a system is of course more prone to errors and audible artifacts (as was dbx’s system) in comparison to either Dolby A or B. But its specs were competitive with dbx.

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