Digital audio engineer James A. Moorer has had an impressive career: He holds multiple patents, has won an Oscar and an Emmy, and was involved in the founding of Stanford’s Center for Computer Research in Music and Acoustics.

But his most famous and familiar work is something that came together in just four days back in the early 1980s. You’ve heard it if you’ve gone to the movies since then, and maybe even if you haven’t. It starts quietly, and it doesn’t last long, but it quickly swirls and builds a kind of thundering tone that can’t be ignored.



It’s the “audio logo” that announces that you’re in a THX-ready theater. It even has a name: Deep Note.

“My wife and I have a running joke,” Moorer told me in a recent interview, “of me going to my grave being famous for 35 seconds.”

The backstory is a curious and seldom-told tale. Among other things, while countless people have heard this brief but mighty composition, most non audiophiles don’t know what, exactly, THX is.







As it happens, Deep Note has just been updated — for the first time in its three-decades-plus history. A new trailer will start booming through theaters in the days ahead. (You can check it out below.)

This makes for a great excuse to revisit the story behind this unusual bit of sound history, along with the momentous yet misunderstood chapter in audio technology that it represents.

What is THX, anyway?

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Moorer in the Lucasfilm Tech Building in San Rafael, Calif., around 1983 (top); Moorer at THX Ltd. San Francisco headquarters in 2014 during his visit to work on the regenerated THX Deep Note. (Photos: © THX Ltd.)



First, let’s get clear on what THX refers to. It is not, as many mistakenly assume, a system for recording, encoding, and decoding audio, like Dolby Digital. It has nothing to do with how sound is captured; multiple formats, Dolby included, can be heard “in THX.”



Instead, THX is essentially a certification system. It originally vouched for the quality of the playback sound system in a theater — a kind of sonic-entertainment Good Housekeeping Seal of Approval. The goal was to guarantee to moviegoers that what they were hearing was as close as technologically possible to what the filmmakers intended them to hear.

As is so often the case, the reasons why this was deemed necessary can be traced back to Star Wars.



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