Debate Thread: Scott's Hi-res Audio Test - Page 94 - AVS Forum
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post #2791 of 2920 Old 08-01-2014, 04:04 PM - Thread Starter
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Originally Posted by 807recordings View Post
Works both ways but I am still a firm believer if there is differences they can be measured and understood.
Our current suite of measurements are woefully inadequate in dealing with dynamic, non-linear distortions. That is why we never use measurements to judge compression artifacts for example. Artifacts vary from frame to frame. No measurement exists to track it. Even if you tracked it, you would have to apply psychoacoustics to each frame to understand what it means.

The far more useful tool is understanding the system itself. You are in test field. So you know the difference between white and black box testing. Measurements are black box testing. You feed an input and see what comes out. Extracting insight into non-trivial systems is very hard that way. White box testing/analysis on the other hand, allows us to drill into the algorithm and focus our testing in that. If we are testing to see how the codec switches between short and long frames, we use a test track that switches between transients and harmonic content. We don't measure anything. Black box testing would be shooting in the dark.

Of course that kind of analysis is beyond the means of many. On purpose I used some signal processing lingo above to demonstrate this fact . Superficial understanding of resampling, requantization, etc. is just not going to work. It would be nice if it were not this complicated but then again, there is a reason people need a proper education and lots of industry and research experience to be successful in this field.

So listening tests become critical and their accuracy paramount as they form the direction of product development/research. We want our human listeners to be as good as measurement tools. This is why we insist on them being trained. This is why any tests of this topic have no value in my book without those types of listeners. We would be sticking our wet thumb in the air trying to determine the temperature.

BTW, didn't mean to pick on your post . Just using it as an excuse to drill down this important topic.

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post #2792 of 2920 Old 08-01-2014, 04:16 PM
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I bow before you, master! ;-)

Just to be clear, my earlier posting was made with reference to "my friend" Tubetwister.
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post #2793 of 2920 Old 08-01-2014, 04:21 PM
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In response from JJ in regard to this thread I was asked to relay this:

"it's JOHNSTON, you idiots, not Johnson.
And
home.comcast.net/~retired_old_jj "

I suspect he will not be in the thread though so I do not know if there will be anything more to add. If there is anything more I will transfer the messages.
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post #2794 of 2920 Old 08-01-2014, 04:29 PM
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Quote:
Originally Posted by 807recordings View Post
In response from JJ in regard to this thread I was asked to relay this:

"it's JOHNSTON, you idiots, not Johnson.
And
home.comcast.net/~retired_old_jj "

I suspect he will not be in the thread though so I do not know if there will be anything more to add. If there is anything more I will transfer the messages.
I hope that's only directed to people who spelled his name wrong. Actually, I hope it's directed at nobody whatsoever unless it's said with a wink and in jest.

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post #2795 of 2920 Old 08-01-2014, 04:38 PM
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Didn't know AAT/Bell labs was working on perceptual encoding as early as they were,more stuff I never knew . Sounds like J. Johnston had/has a pretty impressive career . Interesting ,never heard of him B4 today !
Armirm's info about him and the links were interesting , Have to behave for while ,crawl bots got after me about the mermaid thing it wasn't up long (few minutes) but pretty funny, dang crawl bot's are smarter than I thought!
figured out some of their triggers though antyhing polittikkal <sic> riles them in a hurry maybe I can stay under the radar a little better now !

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post #2796 of 2920 Old 08-01-2014, 04:52 PM - Thread Starter
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Quote:
Originally Posted by 807recordings View Post
In response from JJ in regard to this thread I was asked to relay this:

"it's JOHNSTON, you idiots, not Johnson.
And
home.comcast.net/~retired_old_jj "

I suspect he will not be in the thread though so I do not know if there will be anything more to add. If there is anything more I will transfer the messages.
Please help me understand this. You have an online relationship with a world class audio researcher and signal processing expert, and you decided to use one of your chips with him to come and comment about this thread? You didn't think it was more valuable to reserve that for an answer related to your day job rather than a forum thread? What are the odds of him answering your PMs in the future?

What did you aim for him to address anyway?

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post #2797 of 2920 Old 08-01-2014, 05:15 PM
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"it's JOHNSTON, you idiots, not Johnson.

Oh yeah, that's JJ.
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post #2798 of 2920 Old 08-01-2014, 05:45 PM
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And now 'jj' is much more interested in posting on political and social interest forums.

http://forums.randi.org/showthread.php?t=280922

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post #2799 of 2920 Old 08-01-2014, 06:03 PM
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JJ sides with my camp, at least on this point he addressed to me in another thread:


I have seen, by the way, many speakers and headphones distort with ultrasonic inputs and thereby create audible frequencies.


James D. (jj) Johnston

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He also said to krabbapple once in another thread :

Well, I have heard examples of 30 and 33 kHz being audible via their 3kHz intermod, either in air (the ultrasonic speaker that makes birds chirp at a distance) or in the speaker itself (3kHz is coming right out of the speaker, never mind it's not going in).

I do think that some of the reports we hear are due to exactly such distortion mechanisms, but of course that's not "hearing above 20kHz".


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Sorry, the quote function button isn't working for me right now. It seems to come and go. Don't know why.

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass any more than we get to pick the ending of a play. High fidelity is an unbiased, neutral, exact copy (or "reproduction") of the original source's tonal balance, timing, dynamics, etc..

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post #2800 of 2920 Old 08-01-2014, 06:16 PM
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Quote:
Originally Posted by amirm View Post
Neither. We always call him JJ, on or off the forums.
Very fine Amir; James it is.
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post #2801 of 2920 Old 08-01-2014, 06:17 PM
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Quote:
Originally Posted by arnyk View Post
...

Here's an alternative, equally if not more correct meaning of the same anecdote:

JJ was familiar with a certain audible artifact associated with a certain coder operating at a certain bitrate, which unlike a high percentage of other artifacts was actually obvious over a telephone line. He heard it. That allowed him to identify the bitrate of the MP3 over the phone.
Could he have just guessed correctly?
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post #2802 of 2920 Old 08-01-2014, 06:34 PM
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I have seen, by the way, many speakers and headphones distort with ultrasonic inputs and thereby create audible frequencies.

Hmmm...maybe that brickwall filter at 22 kHz isn't such a bad idea after all.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #2803 of 2920 Old 08-01-2014, 06:42 PM
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Quote:
Originally Posted by 807recordings View Post
In response from JJ in regard to this thread I was asked to relay this:

"it's JOHNSTON, you idiots, not Johnson.
And
home.comcast.net/~retired_old_jj "

I suspect he will not be in the thread though so I do not know if there will be anything more to add. If there is anything more I will transfer the messages.

For the record, I asked him to post this, yes.

Fortunately, this board will tell one one's actual login ID as well as allow one to reset one's password from a decade or so ago.

Amir, be nice to the poor fellow! Goodness.

Whoever called me "James". Only lawyers call me "James".

The "idiot" refers to people who call me "Johnson". I'm a Scotsman, Jim, not an Englishman! Arny, you know better. Grumble!

McNarus, you expect me to be any different after all of the lies people have spread?

Speedskater, what's your point about politics? I gather if you can't discount what someone says, you can play ad-hom, or was that supposed to be a compliment?

Everyone: I have my doubts about everything. I do not intend to participate extensively in this rolling in the mud. Yes, rigorous training is required to do well in a difficult listening test. Yes, people who claim "day and night different" should not expect rigorous training to be necessary. Yes, tests need to be Double Blind, or computer administered for the same purpose. Yes, SACD is still a form of Delta-Sigma, and therefore PCM, no matter what Sony calls it.

Y'all have a nice day, now. Be nice to 807, be nice to Amir, and be nice to Arny.

Fare well.
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post #2804 of 2920 Old 08-01-2014, 06:43 PM
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Quote:
Originally Posted by mcnarus View Post
I have seen, by the way, many speakers and headphones distort with ultrasonic inputs and thereby create audible frequencies.

Hmmm...maybe that brickwall filter at 22 kHz isn't such a bad idea after all.

Or maybe there shouldn't be a brick-wall filter, either, maybe some other kind.

Just sayin', you know.

James D. (jj) Johnston
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post #2805 of 2920 Old 08-01-2014, 06:44 PM
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Quote:
Originally Posted by CharlesJ View Post
Could he have just guessed correctly?
You decide. I don't even remember this happening, but I've done it to people any number of times, almost always based on midrange ickies.

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post #2806 of 2920 Old 08-01-2014, 06:52 PM
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Quote:
Originally Posted by m. zillch View Post


Sorry, the quote function button isn't working for me right now. It seems to come and go. Don't know why.


I have trouble with my Windows 8.1 laptop, but Windows XP PC works fine.
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post #2807 of 2920 Old 08-01-2014, 06:55 PM
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Quote:
Originally Posted by antoniobiz1 View Post

The tested drugs, in Meyer and Moran, are SACD and DVD Audio, as they existed at the time. No custom recordings involved. Just commercially available discs, released to the public and purchasable in most record stores.
The placebo was CD audio Redbook quality (downsampling to 16bit/44.1).
1) The necessary protocols are nothing like a drug test.

2) The three probe signals were CD, SACD, and DVD.

3) CD is not "placebo", it's just one of the test conditions.

Calling CD a "placebo" means you're absolutely sure it does nothing. I'm not even going to go into that here. Or anywhere, really.
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post #2808 of 2920 Old 08-01-2014, 07:10 PM
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Originally Posted by mcnarus View Post
I have seen, by the way, many speakers and headphones distort with ultrasonic inputs and thereby create audible frequencies.

Hmmm...maybe that brickwall filter at 22 kHz isn't such a bad idea after all.
Hmmm... Would you mind adding a little more detail:
1. What was the input source (hardware and signal generation type)?
2. What type of waveform(s):
3. At What Frequency(s)
4. At what Amplitude(s)
5. In what brands and models?
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post #2809 of 2920 Old 08-01-2014, 07:18 PM
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Originally Posted by Garidy View Post
Hmmm... Would you mind adding a little more detail:
1. What was the input source (hardware and signal generation type)?
2. What type of waveform(s):
3. At What Frequency(s)
4. At what Amplitude(s)
5. In what brands and models?

I don't name brands or specific equipment except in very extraordinary circumstances, so he can't possibly know, since he's quoting me, and no, I see no reason to break that rule now, even if I remembered.

I can tell you the signal generator though, it's called "matlab". It makes .wav files. In the place quoted, the frequencies are named. Have fun with that.

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post #2810 of 2920 Old 08-01-2014, 07:20 PM
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Quote:
Originally Posted by jj_0001 View Post
For the record, I asked him to post this, yes.

Fortunately, this board will tell one one's actual login ID as well as allow one to reset one's password from a decade or so ago.

Amir, be nice to the poor fellow! Goodness.

Whoever called me "James". Only lawyers call me "James".

The "idiot" refers to people who call me "Johnson". I'm a Scotsman, Jim, not an Englishman! Arny, you know better. Grumble!

McNarus, you expect me to be any different after all of the lies people have spread?

Speedskater, what's your point about politics? I gather if you can't discount what someone says, you can play ad-hom, or was that supposed to be a compliment?

Everyone: I have my doubts about everything. I do not intend to participate extensively in this rolling in the mud. Yes, rigorous training is required to do well in a difficult listening test. Yes, people who claim "day and night different" should not expect rigorous training to be necessary. Yes, tests need to be Double Blind, or computer administered for the same purpose. Yes, SACD is still a form of Delta-Sigma, and therefore PCM, no matter what Sony calls it.

Y'all have a nice day, now. Be nice to 807, be nice to Amir, and be nice to Arny.

Fare well.


I am so disappointed.

I thought that we were going to hear something about the subject from Jimmy Johnson. After all, JJ only needs to use one ear when he does his audio testing!


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post #2811 of 2920 Old 08-01-2014, 07:28 PM
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I think we'll soon be hearing of yet a new, "night and day" difference anecdote:


"I heard a night and day difference, like a veil was lifted, using only one ear, through a digitally compressed cell phone call, from another cellphone in my wife's kitchen, held away from her head and aimed at the living room."

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass any more than we get to pick the ending of a play. High fidelity is an unbiased, neutral, exact copy (or "reproduction") of the original source's tonal balance, timing, dynamics, etc..


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post #2812 of 2920 Old 08-01-2014, 07:28 PM
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Quote:
Originally Posted by jj_0001 View Post
Whoever called me "James". Only lawyers call me "James".
Alright jj.

Quote:
Originally Posted by jj
Everyone: I have my doubts about everything. I do not intend to participate extensively in this rolling in the mud. Yes, rigorous training is required to do well in a difficult listening test. Yes, people who claim "day and night different" should not expect rigorous training to be necessary. Yes, tests need to be Double Blind, or computer administered for the same purpose. Yes, SACD is still a form of Delta-Sigma, and therefore PCM, no matter what Sony calls it.

Y'all have a nice day, now. Be nice to 807, be nice to Amir, and be nice to Arny.

Fare well.
Nicely said.
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post #2813 of 2920 Old 08-01-2014, 07:36 PM
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Originally Posted by jj_0001 View Post
1) The necessary protocols are nothing like a drug test.

2) The three probe signals were CD, SACD, and DVD.

3) CD is not "placebo", it's just one of the test conditions.

Calling CD a "placebo" means you're absolutely sure it does nothing. I'm not even going to go into that here. Or anywhere, really.
CD is placebo by definition. We don't care if it distorts its content in the worst possible way. The test assumes its quality as zero, and tries to evaluate the benefits that could come from increased sampling rates and bit depths (the drugs). As a matter of fact, the only way that a real placebo can exist is in theory. When testing drugs, even if you drink water you change something in the tested body.

So it's not that "you're absolutely sure it does nothing". It's that we define whatever it does as "nothing".

As for the necessary protocols, they are, IMHO, perfect for a real world evaluation (by that I mean people sitting in front of a pair of speakers, listening to music for a few minutes, and not someone going back and forth listening to 1/8 of a second to the sound of jangling keys - or even music).

On a side note, I don't like your tone a bit.
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post #2814 of 2920 Old 08-01-2014, 07:47 PM
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Originally Posted by jj_0001 View Post
I don't name brands or specific equipment except in very extraordinary circumstances, so he can't possibly know, since he's quoting me, and no, I see no reason to break that rule now, even if I remembered.

I can tell you the signal generator though, it's called "matlab". It makes .wav files. In the place quoted, the frequencies are named. Have fun with that.
I can most certainly respect your decision not to share brands names; it was a lessor concern for me.

I am familiar with some MATLAB products; however, your front-end (D/A - A/D hardware) is important to list in tandem with your MATLAB disclosure. Would you mind sharing this missing information (if you already have - please forgive me, and direct me onward)?

It would be appreciated by me and others.

Thank you
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post #2815 of 2920 Old 08-01-2014, 08:20 PM
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Quote:
Originally Posted by antoniobiz1 View Post
CD is placebo by definition.
Not in the least, it's one of 3 test conditions. There is no "placebo" in this, unless you are referring to null tests.

Level roving tests make switching requirements very clear.

As to material, being able to loop at will is essential, on top of everything else, including level evaluation, in-band frequency response and a bunch of other things that were at least touched on, if I recall correctly.

This is not an easy test to do, and it would be very easy to have either false negatives or false positives.

James D. (jj) Johnston

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post #2816 of 2920 Old 08-01-2014, 08:23 PM
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Originally Posted by Garidy View Post
I can most certainly respect your decision not to share brands names; it was a lessor concern for me.

I am familiar with some MATLAB products; however, your front-end (D/A - A/D hardware) is important to list in tandem with your MATLAB disclosure. Would you mind sharing this missing information (if you already have - please forgive me, and direct me onward)?

It would be appreciated by me and others.

Thank you
Don't actually recall, but of course I could measure the output from the amp, and there was no nasty IMD there.

Also verified that some speakers did not do this, but did have substantial output (nice little ribbon tweeter there).

So that shows where the distortion comes from. Wasn't the mike, wasn't the ADC/DAC, wasn't the amp I was using. But yes, I have seen that problem with amps, as well, just not the one I recall doing the tests that I think are being referred to here with.

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post #2817 of 2920 Old 08-01-2014, 08:29 PM
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Correct me if I'm wrong but even with two "perfect" mono systems (two sets of perfect IM-free sources, amps, and speakers, sitting side by side in the same rooms air space), producing different frequencies, we can still get IM products, in a certain sense, simply in the air itself! We however refer to it as a "beat frequency", not an "IM distortion product", but it's the same thing to the ear.

In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass any more than we get to pick the ending of a play. High fidelity is an unbiased, neutral, exact copy (or "reproduction") of the original source's tonal balance, timing, dynamics, etc..


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post #2818 of 2920 Old 08-01-2014, 08:29 PM
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Quote:
Originally Posted by stereoeditor View Post
I was visiting a friend when JJ called. My friend had ripped some CDs to MP3 and one was playing when he answered the call. JJ correctly identified the bitrate the CD had been ripped at over the telephone (which itself uses lossy compression). Now JJ, of course, is intimately familiar with lossy compression artefacts, having devoted much of his working life to developing codecs. But I was still gobsmacked.

John Atkinson
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What was the bitrate?
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post #2819 of 2920 Old 08-01-2014, 08:36 PM
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Quote:
Originally Posted by m. zillch View Post
JJ sides with my camp, at least on this point he addressed to me in another thread:


I have seen, by the way, many speakers and headphones distort with ultrasonic inputs and thereby create audible frequencies.


J

The "Official" All CD Players Sound the Same Thread


He also said to krabbapple once in another thread :

Well, I have heard examples of 30 and 33 kHz being audible via their 3kHz intermod, either in air (the ultrasonic speaker that makes birds chirp at a distance) or in the speaker itself (3kHz is coming right out of the speaker, never mind it's not going in).

I do think that some of the reports we hear are due to exactly such distortion mechanisms, but of course that's not "hearing above 20kHz".


CD Player recommendations for my setup


Sorry, the quote function button isn't working for me right now. It seems to come and go. Don't know why.

just add [quote***=insert name] ofc without the ***wildcard (can be done multiple times within a posting for serial cut and paste quoting )☺☺☺

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looks like this when done ☺☺
Quote:
Originally Posted by me

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☺ I think krabapple showed me that

Hires Music formats ..............."Why does it sound like a CD ?" ............. can we make it louder "?
"The wireless music box has no commercial value. Who would pay for a message sent to nobody in particular?"
- David Sarnoff's associates at RCA the 1920's -

Last edited by tubetwister; 08-01-2014 at 08:47 PM.
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post #2820 of 2920 Old 08-01-2014, 08:40 PM
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Quote:
Originally Posted by m. zillch View Post
I was a dealer for all three of the SACD players Meyer and Moran used so I know them well. I know for a fact all three had a>b phrase repeat functions which the listener could engage at will from their seated position, via remote. On two of the machines, a SonyES and the Yamaha they say they used predominantly, this function even has its own dedicated remote button making it very easy to access. On the third machine, a Pioneer which I also own, you need to negotiate to the correct menu screen first to get there, but once there it operates quite easily.

BTW, I don't know them well, however I have met both of these fine gentleman, one only passingly at a BAS meeting I co-attended.

Meyer & Moran's (2007)'s experiment did not include training, though few if any of the many, many, many proponents of 'hi rez sound' have had formal 'listener training' (e.g., progressive training to hear artifacts as their level is decreased from 'obvious' to 'inaudible') either. So M&M were merely testing the *common claim by audiophiles* that they can routinely 'hear' hirez vs Redbook. Audiophiles often claim this *even for recordings that are not 'purist' hi rez* -- e.g, ones that went through an analog stage.

Some of M&M's subjects were audio professionals , and some of the trials took place in professional studios.

None of that has stopped the hi-rez dancers from doing their dance about M&M (2007). To them it's a 'no goal' because they (dancers) have moved the goalposts. Now it's only *trained or exceptional listeners* using *pure hi rez' recordings, that demonstrate the magic.
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