Q&A with Tomlinson Holman, Pioneer of THX
In his 35-plus-year career in audio, video, and film, Tomlinson Holman’s research has influenced both film-makers and the movie-going public.
courtesy Irene Fertik, University of Southern California
In his 35-plus-year career in audio, video, and film, Tomlinson Holman’s research has influenced both film-makers and the movie-going public. Maybe you know his work? During a 15-year stint at Lucasfilm, for instance, he developed the THX Sound System. How did THX get its name? Holman told PRO AV.
PRO AV: Did you ever envision that THX would impact so many venues?
HOLMAN: Not in the beginning. I went to Lucasfilm with a mission to change the cinema industry, so I was really focused on that. About 1987, after seven years at Lucasfilm, I went to the Consumer Electronics Show and saw how badly home theater was being done, so I felt I had a role to play there, too. Of course, I have to give credit to Dolby Labs for improving the quality of recording on film, without which there wouldn’t have been much point in improving the cinema sound system and acoustics.
PRO AV: What is the next facet of life that needs better sound?
HOLMAN: What I call public sound. The sound systems and acoustics of many live venues are just intolerable. There are ways around this, but they start with integrating room acoustics and sound systems from the conception of a project.
PRO AV: You talk about “the bitrate of reality.” What do you mean by that?
HOLMAN: That is to say, what does it take to make an aural event indistinguishable from reality? Today that means in a digital universe. There are four items that control the bitrate: bandwidth, dynamic range, spatial capability, and coding. Coding has been thoroughly established as transparent when done correctly (although there are lots of bad implementations). Bandwidth and dynamic range are saturating functions: You get enough to cover human hearing and you’ve got enough—period. So spatial capability is where the action is.
PRO AV: Why do we need 10.2 channels of audio?
HOLMAN: Everyone hears the difference between mono and stereo. Today, you can hardly buy a receiver that isn’t equipped with surround sound, and everybody can hear the difference between 2- and 5-channel sound.
Bandwidth and dynamic range are saturating functions. But the number of channels is not, it’s an asymptotic one—more is better up to the point where you grow increasingly close to reality. I think 10 is the next step beyond 5 for producing enough difference to matter.
PRO AV: Urban legends abound, so let’s set the record straight. Does THX stand for Tom Holman’s eXperiment, or is it from the title of George Lucas’ pre-Star Wars film, “THX-1138?”
HOLMAN: The guy who hired me, Jim Kessler, thought it up. His first thought was that this was Tom Holman’s crossover, abbreviated XVR (though it was also Siegfried Linkwitz’s theory of measurements and curve fitting by Stan Lipshitz and John Vanderkooy, but I had a part, too). He dropped the VR and stuck together TH and X, then realized that also applied to George’s first movie, so it was perfectly appropriate. We later changed the X to mean eXperiment.