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Oppo PM-1: A New Planar Magnetic Headphone! - Page 109

post #1621 of 2487
Quote:
Originally Posted by bcschmerker4 View Post
 

Thanks for some hard info on how the PM-1 responds to a modest amplifier, w/r/t STAX® Earspeaker® headsets on 2kV.  From the overlay chart, the electrostats have an advantage in the mid-treble, but appropriate equalization in the 1.5-5 kHz band should narrow the gap. Definitely close enough to my requirements to be a finalist; I might very well go with the currently-in-development (as of 19 April 2014) Oppo® PM-2 on cost, if it's close enough to the SR-007 in measured performance when a sample arrives for a Head-Fi meet in the future (don't know if a development model will be ready for the July meet at San Francisco).

 

Don't take this the wrong way...but why are you putting trademark signs everywhere in your posts?

post #1622 of 2487

UPDATE: See my later post, below!

Here's something you guys will enjoy discussing...

From Dr. Mark Waldrep (a.k.a. "Dr. AIX" of http://www.realhd-audio.com) :

 

 

Quote:
All audio for films is PCM at 48 kHz/24-bits. The actors are recorded by the production sound mixer at 48 kHz/24-bits, the foley and ADR (automatic dialog replacement) are recorded at 48 kHz/24-bits and the mix is output as part of a DCP (Digital Cinema Package) for final delivery with the visuals...at 48 kHz/24-bits PCM. Nothing high-resolution about any stage of the production. And it gets worse.

For "consistency", there is an aggressive low pass filter applied to the full range audio before you get to hear the soundtrack. It's called the "X-Curve". Sounds pretty exotic, doesn't it? How bad could a little high frequency rolloff be? After all, it's only dialog, a little underscore and a few sound effects, right? It's hugely bad...and I had no idea until today.

The X-Curve is based on the Film Academy curve. See the illustration below (which was borrowed and recreated from an interview with audio pioneer Loan Allen, on the editors guild website)."



As you can see from the graph, the rolloff is very severe and basically removes any frequencies above 10 kHz. Along the way, the X-Curve attenuates more and more high frequency information...3 dB per octave up to 10 kHz and then 6 dB per octave. There's no hope for high-fidelity in a movie house.

And do you think it's any better at home? Nope...the studios that are preparing the 5.1 and stereo mixes for DVD or BD, are shackled with the same source material that was provided to the theater. Why bother thinking about better codecs and Dolby TrueHD for your movies when the content is already so compromised. I'll have to do some checking with my engineer friends about the home theater world. But as far as I know, the same kind of rolloff (although a different curve) is applied to television programming.


See: http://secure.campaigner.com/Campaigner/Public/t.show?6j5yx--3jqrk-vmzdfm5&_v=2

Mike


Edited by zilch0md - 4/20/14 at 9:52am
post #1623 of 2487
Well, luckily we still have music and games to squeeze a bit above 10KHz.
post #1624 of 2487

Yes, indeed!  But I was astonished to discover that motion picture audio deprives us of so much FR, with no evidence of complaint from movie-going, DVD- and BD-renting audiophiles (like me).

post #1625 of 2487
Yeah it kinda sucks... Wonder if there'd be much difference.
Someone should make a version with and without the filter.biggrin.gif
post #1626 of 2487
Quote:
Originally Posted by zilch0md View Post
 

Yes, indeed!  But I was astonished to discover that motion picture audio deprives us of so much FR, with no evidence of complaint from movie-going, DVD- and BD-renting audiophiles (like me).

 

Would that be from this link?

post #1627 of 2487
Quote:
Originally Posted by zilch0md View Post
 

Yes, indeed!  But I was astonished to discover that motion picture audio deprives us of so much FR, with no evidence of complaint from movie-going, DVD- and BD-renting audiophiles (like me).

 

There have been hundreds if not thousands of movies measured spectrographically over at AVS.  I can say with 100% confidence that the graph above does not represent the output seen in any of the measured movies.  Don't know where the chart above came from, but it in no way represents reality.

post #1628 of 2487
Quote:
Originally Posted by griff2 View Post
 

 

Would that be from this link?

 

Yes - or from the link I provided above:

 

post #1629 of 2487
Quote:
Originally Posted by bfreedma View Post
 

 

There have been hundreds if not thousands of movies measured spectrographically over at AVS.  I can say with 100% confidence that the graph above does not represent the output seen in any of the measured movies.  Don't know where the chart above came from, but it in no way represents reality.

 

That's good news!

 

I just dug deeper and discovered that Mark Walberg's graphic (the chart in question) is derived from a graphic seen in the article his article has hyperlinked from "the editors guild website".  On reading that article, don't miss scrolling to the bottom of the page, where you can see it was written 13 years ago!  And, reading that article, it's obvious that the so-called "Academy Curve" illustrates what was happening with motion picture audio "in the 1930's".  Sheesh!  Talk about an outdated reference!  Even the so-called "X-Curve" represents state-of-the-art motion picture audio "in the late 70's."  It's plain as day in the caption under the graphic that Mark Walberg borrowed for his article!

 

My apologies for wasting everyone's time with Dr. Waldrep's interpretation of that dated article.

 

Mike

post #1630 of 2487
Quote:
Originally Posted by zilch0md View Post
 

 

That's good news!

 

I just dug deeper and discovered that Mark Walberg's graphic (the chart in question) is derived from a graphic seen in the article his article has hyperlinked from "the editors guild website".  On reading that article, don't miss scrolling to the bottom of the page, where you can see it was written 13 years ago!  And, reading that article, it's obvious that the so-called "Academy Curve" illustrates what was happening with motion picture audio "in the 1930's".  Sheesh!  Talk about an outdated reference!  Even the so-called "X-Curve" represents state-of-the-art motion picture audio "in the late 70's."  It's plain as day in the caption under the graphic that Mark Walberg borrowed for his article!

 

My apologies for wasting everyone's time with Dr. Waldrep's interpretation of that dated article.

 

Mike

You should probably edit your original post by just cross it out so that people don't mistake it for real information, if they miss this correction post of yours. Your current edit doesn't really say that it's wrong information lol.


Edited by jerg - 4/20/14 at 10:02am
post #1631 of 2487

As a person that works professionally in sound, I was surprised to learn the the X-Curve is still the "law of the land" when it comes to outputting DCP or final film sound. The article may have been written some years in the past, but that doesn't mean that the standard has changed. It hasn't. Every dub stage in Hollywood mixes and outputs the soundtrack using the X-Curve. And that curve does indeed, rolloff the high frequency information above 10 kHz by 6 dB per octave (although it does vary slightly for smaller spaces). You can read Tomlinson Holman's article on the  history of the X-Curve or check out a pdf on the topic at http://www.hps4000.com/pages/special/Dolby_The%20X-Curve.pdf.

 

The fact remains that high-resolution audio isn't happening at the movies. The idea behind the X-Curve was to provide interchangeability and consistency from production to playback. It seems it has accomplished that goal and no one that I'm in touch with is advocating for anything else.

post #1632 of 2487

Guys, the X-Curve is still the SOP for the delivery of film sound. High frequencies are being rolled off in ALL Hollywood blockbusters and even independents...it is the norm. There are numerous sources online that trace the development of the curve (I can't post links because of my newness to this forum). But in talking to engineers doing the actual mixes...the fact is that the soundtracks are still going through this filtering.

post #1633 of 2487
Oh my! Color me confused!

It's a shame your article didn't address the vintage of that guild article, Mark, but I'm still willing to remain open-minded to your findings. Please do post the links you're talking about, when you can. I'll try to research this further on my own, as well.

Don't be discouraged. Fight the good fight, if there's a truth that needs to be heard.

Meanwhile, I'm officially neutral on this topic, until further notice.

Mike
post #1634 of 2487
Quote:
Originally Posted by Dr AIX View Post
 

Guys, the X-Curve is still the SOP for the delivery of film sound. High frequencies are being rolled off in ALL Hollywood blockbusters and even independents...it is the norm. There are numerous sources online that trace the development of the curve (I can't post links because of my newness to this forum). But in talking to engineers doing the actual mixes...the fact is that the soundtracks are still going through this filtering.

 

Does it apply to voices only or the FX and music part as well?

 

I'm working with digital cinema content all day (audio) and there is audio above 10kHz, on all of them. It could make sense to band-limit voice recording (better clarity? Less noise?), actually.

 

According to this document, the X-curve is used to translate what the sound engineer hears in his near-field setup to the expected result in a larger theater room. It is not an equalization or band-pass filtering, it is a calibration curve.

post #1635 of 2487

Excellent paper...definitely worth the read. Please note that I didn't say there was no audio above 10 kHz...just that it is attentuated. The X-Curve is applied to the entire mix, not just the music and effects.

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