Since there are several posts coming all at once, I hope no one will mind if I sort of bundle (or bungle
) my response. First, thanks everyone, for your nice comments. And, Feri, thank you especially! That is high praise.
There is more that I might have tried to say in my last post, but I wanted to keep it simple for clarity and emphasis. But, David has raised some good points about realistic sounds, and music in movies, and this is a great time to try to address them in the context of DEQ. (And, Adam, I am really glad that it is working as intended for you.)
Very few sounds in movies are at all realistic. Think about voices for a moment. Do our voices really sound like that when we are outdoors, for instance? Or are our voices thin sounding, and lacking in timbre, when we are outside? Gary, with his experience in film recording will be able to address this issue better than I can, but I will give a few examples. Are footsteps really as loud as they sound in a movie? Or doors closing? For anyone who has ever been in a fight, or studied martial arts, or even watched MMA, does the sound of a fist striking really make a sharp "Crack!" sound, or is more of a meaty thud? And, do kicks really make any special sound at all, as they always do in movies?
As a former shooter, and one with a military background (there Adam, I said it) I can assure everyone that gunshots, particularly outdoors, don't sound at all like that. The sound is very sharp and quick, not drawn out for dramatic effect, as it is in movies. And, explosions don't sound anything like the way they do in movies. They aren't nearly as prolonged, and they are much, much louder. Burst your eardrums loud, at close range. None of that is intended as a critique. Movies are drama, and sounds are created for dramatic effect, and for a simulation of reality, not for reality itself. And, we willingly suspend disbelief, as we do for the story, and for the visual effects, as part of the entertainment process.
We also become acclimated to "movie sounds" over time and separate them in our minds a bit from real sounds. For instance, anyone who has watched fight scenes, from Western movies made in the 1930's and early 40's, knows that the visual and audio effects of those scenes were much more realistic than the ones that we have grown up seeing. They actually fought just as most people really would. The problem is, that on the screen, they didn't look or sound realistic. The punches happened too fast visually, and there was little sound when they landed (which they often did, in the early movies) or when they appeared to land. They just didn't have any dramatic appeal.
John Wayne and Yakima Canut are credited with revolutionizing movie fight scenes. Long, slow punches, with lots of windup. Loud "Cracks!" when the punches landed. That's just one example, from many that we could think of. But, after a while, we got used to movie and TV sounds, as opposed to real ones and incorporated them into our mental database of how things are "supposed" to sound in a movie. David made a similar point in his analysis of a real train, versus a movie train, which can sound any way the film mixer and director want it to.
But, what about music? Surely, if DEQ were designed to work for music in a 5.1 movie, it would have to work in the same way for a two-channel recording, wouldn't it? Well, yes and no. Others can probably think of other examples, but this is one of my favorites to illustrate the point. Anyone who has seen "Meet Joe Black" will probably remember the climactic scene of the birthday party at the end of the movie. There is a hauntingly beautiful song playing, and there are fireworks going off overhead. Many fireworks, which continue for quite a while. The director and film mixer (probably in collaboration with the composer) do a tremendous job of weaving multiple sounds together, from different channels, at different volumes. At times, the music swells, and the fireworks recede, while two of the characters dance or kiss. (One male/one female.) At other times the music is in the background, and there is dialogue, and sounds from the party. At other times, the fireworks dominate the soundtrack, but the music is always playing, throughout all of that. It's a brilliant job of scoring, in my opinion.
But, if you were to listen to the main theme from the soundtrack, on a standalone basis, you wouldn't hear any of the background party sounds, or dialogue, or fireworks. And, there would be no particular need for DEQ, because there would be no special acoustic balance to maintain, and especially not from individual channels. There wouldn't be a need for a bass boost, so that the fireworks would sound realistic, or for a surround boost, and there wouldn't be a Reference level to compensate for in any way.
In other words, movie music is just part of the overall dramatic presentation in a movie, and is mixed especially with that in mind. If DEQ has any validity at all, it is to maintain dynamic equilibrium for 5.1 movie soundtracks (including the on-screen music) at below Reference volumes. Take the the 5.1 movie, out of the music equation, and the situation changes dramatically.
Nothing I have said reflects my personal opinion on whether or not DEQ actually works exactly as intended for 5.1 movies. It just continues the theme of trying to keep us on the same page, as we discuss how well it works, in the context of its actual design intent.