Originally Posted by jchong
Why do you mention the "cut-off at say 30Hz"? Are you saying that all movies are cut off at that freq?
If let's say a movie was cut-off at 30Hz deliberately, then wouldn't that be part of the intent of the producer/sound designer? He might have heard the unfiltered track then decided to put in a 30Hz filter and listen to that again. If that gets his seal of approval to be put into a bluray, then wouldn't you say what the producer heard and what is on the disc is essentially the same?
The problem is that the studio used for production may not reproduce much below 30hz.
The installations simply does not have the required capacity and extension.
Then it would need proper set-up as well, and since there are no standards describing how this should be done, it is likely that it will be equalized to a flat response, measured by a microphone at some listening position, and thus there will be no compensation for room size.
So it is likely that in many studios there will be no difference by filtering at say 30hz, and there are several confirmed examples of this practice.
I do not think this is done to suit reproduction on small home systems - even the simplest system will have a lf filter to protect, the movie does not need any filtering - it is simply because the producer can not perceive any difference.
If a producer experiences a sound effect that has full bandwidth, on something that is capable of reproducing at least some of it, the difference is very real and not subtle at all, and would of course want this in the movie. That some playback systems will have a hard time reproducing it would not be of concern.
Avatar is an example of a movie where the bass would be so much better if it had more extension down low and more dynamics.