Originally Posted by DS-21
You may have taken the first step, showing the presence of ULF in one piece of music. But you haven't done the one thing that would make your position have merit beyond the world of special effects bombast*. That is, you've not made any showing whatsoever that the ULF signal that you have shown to merely exist in one commercial music recording is intentional by pointing out how it correlates with the music.
No, it's about a factual inquiry that provides data reasonable people can use to determine whether or not it is subjectively worth it to them, considering the program material they enjoy and expect to enjoy, to pursue extremely low LF cutoffs in their systems, or to use a higher cutoff and focus more on efficiency/output from that LF cutoff up. Why you wish to personalize it is beyond me.
The problem I have with your line of interrogation is that you feel you can put myself or others on the spot while you remain intellectually lazy.
I've posted the following info many, many times over the past decade in many forums. It is info from many hours of research of studies, lab grade measurements results and examination of recorded source.
I use a Mac myself, but I bought a dedicated Windows PC and state of the art measurement equipment because Mac users are generally graphics people and not acousticians.
Why on earth you think it's incumbent upon me to find you hardware/software solutions is not worth thinking about. Get busy or take my word for it or stay ignorant, means nothing to me either way.
Let's start with the basic fact of life regarding ULF content in sound in the real world:
|Virtually all musical attack transients actually contain an infinite spread of frequencies, extending all the way down to DC and as high as the risetime of the attack warrants.
Results of measurements of the onset of a violin string, upright bass string, piano string, etc., pluck, hammer strike or whatever, have confirmed this phenomenon many times in many studies and tests. Here are the spectrograms of a few of them:
Here's a simple experiment I did myself. I recorded an actual door slam in my HT and compared it to a Foley door slam from a popular movie:
I scaled and laid over the 80 phon Equal Loudness Curve to show that a typical door slam follows what science has told us human hearing has adjusted to over the millennia, as most real event naturally occurring loud transients do. So, would you say that the Foley door slam is more realistic after having the ULF filtered in the recording process? You may take the easy way out and say it doesn't matter, but how can you possibly take the position that including the ULF content in that same movie soundtrack door slam would be unintended artifact or in any not more realistic?
There are consultant companies that make millions of dollars by (among other things) designing car door mechanisms and seals that purposely attenuate higher frequencies, therefore accentuating the ULF, which humans perceive as being of higher quality. This is not because the ULF is 120 dB when you close your car door, or pluck a violin string at 1,000 Hz fundamental, etc.
Would you say that, for example, if your preference in music is for live recording full orchestra classical, you get a more realistic reproduction of the transients if the recording or the playback system is filtered at 20 Hz or the entire process was unfiltered?
That's a rhetorical question. There isn't any question as to which method is truer to the real event.
As far as what recordings you might prefer to buy and their ULF content or lack thereof, have at it. If you're as discriminating an audiophile as you let on, you should be as discriminating in screening the recordings you buy.
I personally have a few dozen MC SACD and DVD-A music discs and otherwise don't buy/listen to music because most recordings are compressed, filtered, synthesized, effects affected garbage. So, I'm the wrong guy to ask to act as your filter. I don't care what recordings you like or dislike, nor do I care what system you prefer to play them back on. That's irrelevant to the Q.
As far as movie soundtracks, there is no question whatsoever, except to the most clueless poster, that the content is there, it is intended and it adds to the presentation to a significant degree. Whether one prefers it or not is not the question.
When I bought Pearl Harbor I was still using a big pair of (10 ft^3) ported boxes, each with 1-18" driver. They were from the ProLogic system and I believe they were tuned to 25 Hz. There were scenes in that movie that shook the room, but as I moved deeper into things I pretty much put the disc on the shelf as unworthy to collect dust.
I recently read an article that talked about <20 Hz content in the soundtrack, so I pulled it out and graphed a bunch of scenes. Here are 2 scenes that are pertinent to this thread. First, is the onset of the Japanese attack on the Pearl harbor fleet:
When you remove everything below 20 Hz, it should be obvious what the difference in presentation might be. Yes, to me it was like watching a whole new movie.
Here's another scene where Zeroes are strafing:
If you take everything below 20 Hz out of this scene, it becomes a complete non-event, certainly nothing like a real pair of low flying 20mm canons strafing you. Conversely, it's a whole new experience as recorded.
Like it or not, the facts are indisputable. Leave it in = more realistic. Take it out = not. Personal preference, budget and taste are irrelevant here. There are plenty of threads that focus on those aspects, but answering the question; "Purpose of a flat response below 20 Hz - why does it matter?" is specific enough to exclude all of that noise.