Chapter 2: Historical Context: From Dolby to THX
THX created “Reference Level” to match theater playback to the mixing studio, but listeners routinely turn it down for being too loud.
As far as standards go, back in my youth, it was kind of the epitome of the Spaghetti Western’s Wild west. Dolby was doing Dolby, effectively pushing Dolby Surround matrix encoding/decoding left/right phase differences into a mono two-speaker ‘surround’ component on existing 2-channel stereo formats. That eventually became known as Pro-Logic with an actively steered center channel.
Back when the dinosaurs of big fat full-range speakers ruled the earth (we just called them speakers), when it came to the question of “how much do I need?”, generally people either largely didn’t care, or they were still following the aftermath of the “Watt Wars” of the 70s, and the answer came down more to budget. You bought what you could afford, and if your priorities included loud, that meant big speakers, and big amplifiers.
And if we were talking honest power, back then the most cost-effective power-delivering topology that had any mainstream HiFi cred was largely Class AB amplification with linear power supplies, which meant Big Iron, big heat sinks, and if you had more than a couple hundred watts per channel via an outboard amplifier, people considered you a maniac. In college, I became that maniac, and none of my neighbors appreciated it.
As far as a ‘correct’ listening level goes, there was no such thing, and no one really cared. It was whatever you enjoyed, loud enough to hear everything, but not so loud that it became unpleasant. And as that level is subject to personal subjective experience, it made sense that people using audio systems at home for music or movies, either with Betamax or VHS tape, or for those who were super fancy, Laser Disc, in glorious CRT-rendered 480i, never bothered to even wonder what the playback level should be. Most of us had never heard about people using an SPL meter, let alone calibrating system playback. We ran it, and we liked it, or we bought something else.
And along came THX, a bearer of blessings that would make a nun blush, and among other things, more stuff to buy.
THX brought the notion of ‘Reference Level’, a standardization system intended and sold as a quality control program for commercial theaters by Lucas Films - THX was invented by audio scientist Tomlinson Holman at Lucasfilm in 1983. It was developed to ensure that the soundtrack for Star Wars: Episode VI - Return of the Jedi would be accurately reproduced in high-quality venues.
In commercial theaters, you cannot give everybody a ticket to their own remote. They’re all listening to the same thing, and they’re all going to have different preferences. So, as society demands sacrifices from individual freedom to work, this standardization component kind of made a whole lot of sense in commercial theaters. Pick a playback level that works well for most everybody, and stick to it, through the entire chain, from production to playback.
Who gets to decide playback levels? Well, leave it to the expert, the director! Or, at least leave it to those delegated by the director, and hope they make good choices.
The “Director’s Intent” may be the most successful marketing phrase ever imported into consumer audio. The unforgiving truth is that most people won’t sit through a film in the same room, on the same speakers, at the same level, under the same conditions as the mix engineer. How many of us have actually been in a dubbing theater and listened to the mix at reference level? Yet we’re expected to treat a volume knob like a sacred covenant, leading us to aspirations of hitting “reference”, and it would seem that our future might become even louder.
In time, this standard was more miss than hit on a performance level. Despite this, THX Certification became one of the most recognizable badges in consumer audio, simultaneously serving as both an engineering standard and an extraordinarily effective marketing tool by boasting the clout and substance of cinema audio to consumer audio. There were some gains as far as standardizing minimum performance criteria, albeit tactically kept ambiguous from public view for pretty logical reasons, such as IP protection. There are a lot of personal anecdotes and professional assertions that indicate that a ‘THX correctly certified’ playback level is way too loud.
Reference Link: THX Blog THX Loudness
Reference Link: THX Reference
Reference Link: Acoustic Frontiers Reference Level Explained
People would complain in one direction, managers would turn it down based on the squeakiest wheel, and the standard of ‘Reference Level’ slid down the slope of ambiguity, unreliably, behind closed doors, in practice and due to popular demand.
Reference Link: SMPTE 2024 Media Technology Summit (Hollywood, CA)
THX built technologies around the reality that listeners routinely turn playback down. SMPTE researchers found theaters routinely operating below reference. Streaming platforms have made playback consistency more uncertain than ever. Yet the assumption persists that the standard itself remains beyond question.
A standard is supposed to describe reality. When reality routinely ignores the standard, there are only two possibilities: the public is wrong, or the standard is incomplete. One of those explanations is much more comfortable than the other.
And then THX came home, again in a mixed gift bag.
I want to be clear, I think THX offered a lot of good results, forcing an audio industry that largely disregarded many elements of performance in favor of ‘panache’ to pony up products that in some way prioritized peak output capabilities, lower distortion, flatish on-axis frequency response, relatively even horizontal dispersion from the front speakers, and reasonable low frequency audio system extension capabilities, and… SPL. A lot of those things, when the consumers got a taste for them, they really liked it, more than their breakfast cereal. I liked a lot of it. I still have some professional studio monitors that participated from the beginning in that program.
In a lot of ways, I think the THX program pushed the loudspeaker industry forward, at first kicking and screaming and then gleefully upon discovering the sales value of wearing that THX badge. I remember in a training class meeting a custom installer who LOVED THX systems, specifically because they were so easy to sell. ‘Reference Level’ came with that marketing maneuver.
Come back next week for Chapter 3.
Originally published by Totally Hypeless
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