I’ll offer a counterpoint to everyone’s complaints. When I do go which is seldom we go to Dolby Prime movies. The experience is always outstanding with a great A/V experience. While expensive it’s worth the price of admission.
What Dolby is doing with the Dolby Prime cinemas is the same thing THX set out to do but has fallen flat as of late. set standards to ensure everyone gets the same great experience. This post just shows how critical the THX and now Dolby model is.
I’ve been researching a future tech article on volume levels in theaters. The reason volume is down is because people have complained about the volume levels being too loud. Theaters are now under attack by family groups and hearing protection lobbying groups who believe cinemas are dangerously loud. All of this spurred by recent complaints from consumers about the sound being annoyingly and uncomfortably loud. One group did a study and found cinemas were exceeding 118dbs at some seating locations.
The problem is that this hearing protection group and consumers are wrong! I feel absolutely confident in saying that. First, because 118dB was measured C weighted with a movie using a dosing meter. The fact that they hit 118dBC is not shocking, but they fail to understand a key point, that was very likely bass, and 118dB is not dangerous at bass frequencies. It’s only modestly dangerous at higher frequencies, especially since it was a a peak. It’s also possible that the 118dB was an LCPeak value, meaning unfiltered and instantaneous peak. If that is the case, it’s of trivial value in understanding dangers to hearing.
Further, consumer complaints are largely and likely caused by a different effect. Studies into modern soundtracks have found that they are now louder and more dynamic than in the past. The move toward digital alone suddenly added 10db’s to the dynamic peaks being measured in soundtracks. Loudness wars have entered movies in an odd way where sound engineers are now mixing soundtracks and effects at the limits of what is allowed in the standards. That means a highly compressed music soundtrack might be layered in so it plays back at 100db average, because why not. Well 100db music is pretty loud (and in fact in dolby theaters it can now be much louder than this).
Studies into all this began to surmise that distortion might be the culprit. While the ol’ 105dB peak output of each LCR speaker at 1/3rd back has existed for decades, the reality was that the vast majority of cinema speakers can barely hit that value. The lack of a reasonable distortion threshold for that number also means that many may have met that number in its dreams. One study noted that while THX had distortion thresholds, very few theaters are THX certified these days and SMPTE does not. It’s well known that distortion from overdriven speakers (frequently a lot of odd harmonics) is irritating. We tend to turn it down even if we don’t recognize it as distortion. Sure enough a study group went into a bunch of theaters and found that many of the speakers distorted audibly (and of course measurably) near the limit.
So I conclude that people aren’t complaining because it’s too loud in absolute terms. I think the volume levels are fine. It’s because the systems are being driven beyond their comfortable limits. Unfortunately many theaters likely have speakers that are too old, too small for the room, and driven by too little power. It makes what THX tried to do more important than ever. What Dolby and AMC have done is great, but we need this to be universal across the board. Accepted and followed standards.
