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Xiph answers to PONO marketing Digital Converters
Old 2nd August 2014
  #31
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I don't know what is meant by moderate in this case, but I do know this:

Apart from problem samples, the differences between high-bitrate lossy files (using a good, modern encoder) and lossless 16-bit 44.1k PCM have gone away for every listener in every test I have ever been aware of, no matter how big the differences were when the listener knew which was which.

I'm not saying you can't hear a difference, but if you can prove it you would literally be the first I'm aware of.
Old 2nd August 2014
  #32
Quote:
Originally Posted by dogma View Post
Well thats just rubbish. To claim there is no distinguishable difference between orignal and moderate bitrate Mp3 AAC - well distinguishable and moderate are malleable terms - hardly fit for Mr ABX double blindfold. Can you tell the difference between them I sure as hell can

I recommend you to read the "lossless formats" paragraph in its entirety. You are cherry picking some fragments from a text you obviously haven't understood.

Quote:
It's true enough that a properly encoded Ogg file (or MP3, or AAC file) will be indistinguishable from the original at a moderate bitrate.

But what of badly encoded files?

Twenty years ago, all mp3 encoders were really bad by today's standards. Plenty of these old, bad encoders are still in use, presumably because the licenses are cheaper and most people can't tell or don't care about the difference anyway. Why would any company spend money to fix what it's completely unaware is broken?

Moving to a newer format like Vorbis or AAC doesn't necessarily help. For example, many companies and individuals used (and still use) FFmpeg's very-low-quality built-in Vorbis encoder because it was the default in FFmpeg and they were unaware how bad it was. AAC has an even longer history of widely-deployed, low-quality encoders; all mainstream lossy formats do.

Lossless formats like FLAC avoid any possibility of damaging audio fidelity [23] with a poor quality lossy encoder, or even by a good lossy encoder used incorrectly.

A second reason to distribute lossless formats is to avoid generational loss. Each reencode or transcode loses more data; even if the first encoding is transparent, it's very possible the second will have audible artifacts. This matters to anyone who might want to remix or sample from downloads. It especially matters to us codec researchers; we need clean audio to work with.
Learn to read! I took the time to mark bright pink what you guys oversaw. :D
Old 2nd August 2014
  #33
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Quote:
Originally Posted by haberdasher View Post
I don't know what is meant by moderate in this case, but I do know this:

Apart from problem samples, the differences between high-bitrate lossy files (using a good, modern encoder) and lossless 16-bit 44.1k PCM have gone away for every listener in every test I have ever been aware of, no matter how big the differences were when the listener knew which was which.

I'm not saying you can't hear a difference, but if you can prove it you would literally be the first I'm aware of.
This has been my experience too. It's impossible to statistically tell the difference between, for example, a 16 bit original .wav file, against a recently compiled LAME encoded MP3 file at 320 kbps. Have you guys actually done this ABX test recently?

Hydrogen Audio have been performing these listening tests for years, and so far NO ONE on there has been able to statistically tell the difference.
Old 2nd August 2014
  #34
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I can tell the difference between mp3 and CD, and DVD and Blu-Ray, and Paula Deen and Kate Upton.
Old 2nd August 2014
  #35
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I'd be surprised if anyone couldn't. They all look completely different.
Old 2nd August 2014
  #36
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Quote:
Originally Posted by Hermetech Mastering View Post
This has been my experience too. It's impossible to statistically tell the difference between, for example, a 16 bit original .wav file, against a recently compiled LAME encoded MP3 file at 320 kbps. Have you guys actually done this ABX test recently?

Statistically you're probably right. But the programme must be taken into equation as well as who is under testing procedure.
As we run such tests here on a more or less regular basis our conclusions are slightly different from above, or should I put it this way- they're not that certain. For example many common listeners can give up easily before 192 kbps (mp3), but good ears, especially those fimiliar with recording space where the recording was done, seem to be much more tough opponent to lossy codecs, even more tough than some MEs.
We have recently worked on some acoustic production recorded quite well somewhere in NYC, and on sparse parts, where there were no many sources that could mask the rest of signal, we only gave up at 400 kbps aac (we mostly use Fraunhoffer Pro Codec, we stopped to use Lame some time ago and I can't actually remember for what reason), 320kbps mp3 was relatively easy to catch- above 90% hits here (avg from all listeners). On dense parts we hit around 60% at 320kbps (mp3), so we can simply assume the difference could not be caught then. And we're talking about single case/track only and there are many many variables. These are of course very simple recent observations (we ran those tests in an order- first sparse parts and then (several minutes later) dense parts when we were rather tired, but we were forced to accomplish it this day because of companionship), etc.

Art
Old 2nd August 2014
  #37
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right, that's what i would expect - 90+% of listeners of real music should be able to tell the difference even at the highest bitrates. i found a photo of one of these mythical internet tests where people can't tell the difference...i wonder why...
Old 2nd August 2014
  #38
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Quote:
Originally Posted by ArtSta View Post
Statistically you're probably right. But the programme must be taken into equation as well as who is under testing procedure.
As we run such tests here on a more or less regular basis our conclusions are slightly different from above, or should I put it this way- they're not that certain. For example many common listeners can give up easily before 192 kbps (mp3), but good ears, especially those fimiliar with recording space where the recording was done, seem to be much more tough opponent to lossy codecs, even more tough than some MEs.
We have recently worked on some acoustic production recorded quite well somewhere in NYC, and on sparse parts, where there were no many sources that could mask the rest of signal, we only gave up at 400 kbps aac (we mostly use Fraunhoffer Pro Codec, we stopped to use Lame some time ago and I can't actually remember for what reason), 320kbps mp3 was relatively easy to catch- above 90% hits here (avg from all listeners). On dense parts we hit around 60% at 320kbps (mp3), so we can simply assume the difference could not be caught then. And we're talking about single case/track only and there are many many variables. These are of course very simple recent observations (we ran those tests in an order- first sparse parts and then (several minutes later) dense parts when we were rather tired, but we were forced to accomplish it this day because of companionship), etc.

Art
Exactly, I didn't say one couldn't tell the difference after extended listening, or that they sounded exactly the same, just that in ABX tests it's been impossible for me, and the few other people I've tested, and the many people I've interacted with on Hydrogen Audio etc., to be able to statistically tell the difference in an ABX test. I really encourage people to do this test for themselves, because they are usually shocked by the results, especially the ones constantly bemoaning the quality of lossy audio.

My tests have mostly been with modern pop style music too, which can sounds a bit naff anyway. I have had slightly better results with my own tests on high dynamic range well recorded stuff, Steely Dan etc.
Old 2nd August 2014
  #39
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Quote:
Originally Posted by Hermetech Mastering View Post
I really encourage people to do this test for themselves, because they are usually shocked by the results, especially the ones constantly bemoaning the quality of lossy audio.
Oh yes, certainly

Art
Old 2nd August 2014
  #40
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you guys serious? sorry to hear that. i get near 100% in a blind test.
Old 2nd August 2014
  #41
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OK, feel free to post the ABX logs then. PCM vs 320kbps LAME with no funny command line options, just to be fair.
Old 2nd August 2014
  #42
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no need to go to that trouble for something so obvious.
Old 2nd August 2014
  #43
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Originally Posted by Deleted User View Post
no need to go to that trouble for something so obvious.
It really isn't. If you're that certain, you've probably never assisted an ABX test. It's deeply disillusioning I tell you! First thing ABX tests do is to break ppl!

Here's good info on ABX (including several test results):
Links to blind listening tests - Hydrogenaudio Forums
Old 2nd August 2014
  #44
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Originally Posted by Deleted User View Post
no need to go to that trouble for something so obvious.
Well if you can't prove it, then why should we believe you? If you post the results of your tests, and they are near 100%, then I'll eat my compressor, and video myself doing it.
Old 2nd August 2014
  #45
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Justin Colletti had a great challenge, same thing, about a year ago, prove you can hear the difference and he'll run an article about you and your golden ears. No one succeeded...

Think You Have Golden Ears? Take the Scientist Challenge!
Old 2nd August 2014
  #46
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Just took another blind test, 320 mp3 vs. CD. Got it right of course. Maybe some people can't hear it but I find it very easy. Maybe if I installed ABX software and fried my brain taking the test over and over, I'd get it wrong once eventually, but who cares?
Old 2nd August 2014
  #47
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You need to repeat the test over and over, otherwise the results are not statistically relevant, that's the whole point of scientific ABX testing... Or are we talking about completely different things here?
Old 2nd August 2014
  #48
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i find a more statistically relevant method is to test different material at different times. i more or less always get it right so the conclusion is obvious. repeatedly testing the same file over and over again is susceptible to your mind playing tricks on you, or more to the point for me, is just an unnecessary waste of time.
Old 2nd August 2014
  #49
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ok, you're a golden-eared god. we get it.
Old 2nd August 2014
  #50
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Quote:
Originally Posted by Deleted User View Post
i find a more statistically relevant method is to test different material at different times. i more or less always get it right so the conclusion is obvious. repeatedly testing the same file over and over again is susceptible to your mind playing tricks on you, or more to the point for me, is just an unnecessary waste of time.
I get that, and I agree with you for the most part, I don't think ABX testing is the be all and end all of measuring the human perception of sound quality. I also prefer the idea of absorbing whole albums (lossy vs. lossless), and coming to the decision that I'm pretty sure I preferred the lossless one. But you have to realise that if you are going to start saying that it's easy for you to hear the difference, without scientific proof, then many here will not take you very seriously. The only way to scientifically prove you can hear a statistically relevant difference is via ABX tests, even if you (and I) don't really like the idea of them.

Why not do the tests, prove us wrong, submit them to the Hydrogen Audio forum, and Justin Colletti's "Trust Me, I'm A Scientist" blog, and get an article written about yourself, your studio, and your golden ears? What do you have to loose?
Old 2nd August 2014
  #51
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Not interested in scientific proof, no time for that.
Old 2nd August 2014
  #52
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Yeah, I can pretty much always tell when a drum track was recorded on a Tuesday, or if the mix engineer took a taxi to the studio, or whether a red guitar was used, or whether the mastering was done while there was someone called Ned in the room.

I've got no time to actually test my perception, but I'm confident I'm right.
Old 2nd August 2014
  #53
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what dude like i said this is very easy for anyone musical to hear, i just don't care to take abx tests to prove it to skeptics on the internet.
Old 2nd August 2014
  #54
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Under certain circumstances, ABX testing can minimise *discernability* of very small differences, but it's also a very flexible procedure that doesn't need you to focus your listening for long periods unlike, say, mastering an album.

If you can get, say, 9/10 correct results, using the same or different songs each time if you like, only doing one test a day (and for large differences, that should be less than about a minute) that would be impressive.
Old 2nd August 2014
  #55
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Man don't you have the ears to hear the difference between a red guitar and the other colours? Sorry to hear that.
Old 2nd August 2014
  #56
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Originally Posted by Deleted User View Post
Not interested in scientific proof, no time for that.
Quote:
Originally Posted by Deleted User View Post
what dude like i said this is very easy for anyone musical to hear, i just don't care to take abx tests to prove it to skeptics on the internet.
**** like this impresses no one, and just makes you look foolish.
Old 2nd August 2014
  #57
arf
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This debate may finally have been put to rest. Here's an abstract from a paper about to be presented at AES in October. Key quote:

Two main conclusions are offered: first, there exist audible signals that cannot be encoded transparently by a standard CD; and second, an audio chain used for such experiments must be capable of high-fidelity reproduction.

The Audibility of Typical Digital Audio Filters in a High-Fidelity Playback System—Helen M. Jackson, Meridian Audio Ltd. - Huntingdon, UK; Michael D. Capp, Meridian Audio Ltd. - Huntingdon, UK; J. Robert Stuart, Meridian Audio Ltd. - Huntingdon, UK

This paper describes listening tests investigating the audibility of various filters applied in high-resolution wideband digital playback systems. Discrimination between filtered and unfiltered signals was compared directly in the same subjects using a double-blind psychophysical test. Filter responses tested were representative of anti-alias filters used in A/D (analog-to-digital) converters or mastering processes. Further tests probed the audibility of 16-bit quantization with or without a rectangular dither. Results suggest that listeners are sensitive to the small signal alterations introduced by these filters and quantization. Two main conclusions are offered: first, there exist audible signals that cannot be encoded transparently by a standard CD; and second, an audio chain used for such experiments must be capable of high-fidelity reproduction.
Convention Paper 9174
Old 2nd August 2014
  #58
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Quote:
Originally Posted by Deleted User View Post
Not interested in scientific proof, no time for that.
Great!
Old 3rd August 2014
  #59
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Originally Posted by arf View Post
This debate may finally have been put to rest.
I'm not really sure. I'll wait and see if their methodology withstands a peer review. The fact that the paper is still unpublished and that all authors have the same employer doesn't really give me much confidence.

The assumptions/conclusions are interesting, I can't wait to hear this audible 96kHz sound that disappears if converted down to 44.1kHz. Let's hope we don't have to buy a Meridian Audio amp before being able to do so

Interestingly, Monty's article mentions an author of this paper under "further reading", with the comment:

Quote:
Coding High Quality Digital Audio by Bob Stuart of Meridian Audio is beautifully concise despite its greater length. Our conclusions differ somewhat (he takes as given the need for a slightly wider frequency range and bit depth without much justification), but the presentation is clear and easy to follow. [Edit: I may not agree with many of Mr. Stuart's other articles, but I like this one a lot.]
Old 3rd August 2014
  #60
arf
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