Factual error: Throughout the movie, whenever the sunglasses/contacts are worn, both visual and audible hidden subliminal messages are seen and heard. Such as the hidden "obey" message flashing, or the hidden traffic siren repeating "sleep," etc. The problem is that the glasses/contacts only help the eyes, not the ears. So the hidden audio shouldn't be heard any differently or clearer than it is with them off.
Suggested correction: The glasses/contacts are made of a material that blocks the alien signal, hence why wearing them too long makes you feel sick since it messes with the brain. That would allow you to hear the audio as well.
Not true. Yes, the glasses would help you to be aware that the sounds existed; however, the error is that the sounds become louder. Take the traffic signal device. If it is saying "sleep sleep" as a subliminal message outside normal human hearing, wearing the glasses won't change the volume of the subliminal "sleep message" from "sleeeep" to "SLEEEP". Unless you're saying the sounds were always at normal human hearing levels.
That's exactly what was happening. There's a difference between frequency and volume. A sound can have a frequency outside normal human perception and still be loud. For example, a dog whistle is loud enough to hear, but not in a frequency most humans can hear. The plot of the film seems to be that the frequency isn't picked up by the conscious mind, but by the subconscious mind, much like the visual images.
I just assumed, as is the case with most subliminal audio, that the sound messages were a case of low volume and not frequency. That is, sounds that were just below normal hearing volume. That is barely hearable to the average person volume-wise, but they heard enough for the brain to perceive them and process the information subconsciously. Unfortunately, I can only speculate which it is without an absolute answer, so I can't argue the correction really.
