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A secret "known by signal processing experts" or nonsense?
adamdea
post Jan 10 2013, 17:16
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http://www.wickeddigital.com.au/index.php/...eally-necessary
Sets out what is described as a White Paper by Marco Manunta of M2Tech. It contains the following passage (my emphasis)

"But there is something more. Itís known by signal processing experts, and absolutely not popularized amongst music lovers, that converting an analog signal into a discrete-time one (as it happens when converting from analog to digital) destroys the phase information in the two top octaves of the resulting spectrum. In a CD-standard digital recording, all phase information are lost from 5.5kHz up to 22kHz,"

Can any signal processing experts comment on whether this is true or not, and if so why. As a mere layman I am not able to understand why it even might seem be true.
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greynol
post Jan 11 2013, 20:32
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Detection of phase differences between channels does not go away by virtue of using headphones. If anything it is likely enhanced.

While I entertain getting to the truth on this specific issue, I fear it's getting off-topic. Not like there is much more to say on the matter that is on-topic.


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mzil
post Jan 11 2013, 21:31
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QUOTE (greynol @ Jan 11 2013, 15:32) *
Detection of phase differences between channels does not go away by virtue of using headphones..

What goes away is the ability of the L and R waveforms to interact and constructively and destructively collide with each other in the air, causing a ripple effect in the overall frequency response of peaks and nulls, which he is pointing out may theoretically in some circumstances, he stated, be audible. At least that's what I got out of it, but I'm sure he'll explain if I was right or wrong.

It is on topic to the opening post's query regarding phase anomalies in the top octaves:

QUOTE
destroys the phase information in the two top octaves of the resulting spectrum. In a CD-standard digital recording, all phase information are lost from 5.5kHz up to 22kHz,"


Which ABK and I are in agreement was "not pretty numerically" in some of the very early CD players:
QUOTE
So even the old CD players with analog filters did have fairly well matched channels, and while what they did to phase was not numerically pretty, there wasn't any serious effect.

And which I also originally pointed out wouldn't be expected to be audible anyways, before he even joined the conversation:
QUOTE
Humans aren't very sensitive to phase in the very top frequencies anyways, so it wouldn't matter.
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Posts in this topic
- adamdea   A secret "known by signal processing experts" or nonsense?   Jan 10 2013, 17:16
- - greynol   It's complete nonsense. But hey, it's the ...   Jan 10 2013, 17:31
- - saratoga   QUOTE (adamdea @ Jan 10 2013, 11:16) Can ...   Jan 10 2013, 17:33
- - DonP   QUOTE (adamdea @ Jan 10 2013, 11:16) http...   Jan 10 2013, 17:44
- - jmvalin   QUOTE (adamdea @ Jan 10 2013, 11:16) ...   Jan 10 2013, 18:19
- - Kohlrabi   Their website is filled with various other nonsens...   Jan 10 2013, 18:33
- - eahm   Thank you adamdea, now we all need a 5.6MHz/1mbit ...   Jan 10 2013, 19:01
- - mzil   QUOTE (adamdea @ Jan 10 2013, 12:16) http...   Jan 10 2013, 19:54
|- - db1989   QUOTE (mzil @ Jan 10 2013, 18:54) However...   Jan 10 2013, 21:09
- - adamdea   Thanks everyone, I thought it seemed like nonsense...   Jan 10 2013, 23:08
|- - Arnold B. Krueger   QUOTE (adamdea @ Jan 10 2013, 17:08) Than...   Jan 11 2013, 16:58
|- - dhromed   QUOTE (Arnold B. Krueger @ Jan 11 2013, 16...   Jan 11 2013, 17:12
||- - saratoga   QUOTE (dhromed @ Jan 11 2013, 11:12) QUOT...   Jan 11 2013, 17:22
|- - mzil   QUOTE (Arnold B. Krueger @ Jan 11 2013, 11...   Jan 11 2013, 17:58
||- - Arnold B. Krueger   QUOTE (mzil @ Jan 11 2013, 11:58) QUOTE (...   Jan 11 2013, 21:31
||- - mzil   QUOTE (Arnold B. Krueger @ Jan 11 2013, 16...   Jan 11 2013, 23:33
||- - Kees de Visser   You're being mean with old men (like me)   Jan 12 2013, 10:25
|- - Ethan Winer   QUOTE (Arnold B. Krueger @ Jan 11 2013, 10...   Jan 11 2013, 21:27
||- - jmvalin   QUOTE (Ethan Winer @ Jan 11 2013, 15:27) ...   Jan 11 2013, 22:26
||- - Ethan Winer   QUOTE (jmvalin @ Jan 11 2013, 16:26) Actu...   Jan 12 2013, 19:32
||- - Woodinville   QUOTE (Ethan Winer @ Jan 12 2013, 10:32) ...   Jan 12 2013, 20:21
|||- - Ethan Winer   QUOTE (Woodinville @ Jan 12 2013, 14:21) ...   Jan 13 2013, 20:03
|||- - jmvalin   QUOTE (Ethan Winer @ Jan 13 2013, 14:03) ...   Jan 13 2013, 20:17
||- - jmvalin   QUOTE (Ethan Winer @ Jan 12 2013, 13:32) ...   Jan 13 2013, 08:46
|- - Woodinville   QUOTE (Arnold B. Krueger @ Jan 11 2013, 07...   Jan 12 2013, 20:17
- - Arnold B. Krueger   QUOTE (adamdea @ Jan 10 2013, 11:16) http...   Jan 11 2013, 03:58
- - greynol   Detection of phase differences between channels do...   Jan 11 2013, 20:32
|- - mzil   QUOTE (greynol @ Jan 11 2013, 15:32) Dete...   Jan 11 2013, 21:31
- - greynol   @Ethan: I hope this isn't, "I tried it on...   Jan 11 2013, 21:32
|- - Ethan Winer   QUOTE (greynol @ Jan 11 2013, 15:32) I ho...   Jan 11 2013, 22:00
- - greynol   I did not take the OP as meaning phase relation be...   Jan 11 2013, 21:39
- - Woodinville   QUOTE (adamdea @ Jan 10 2013, 08:16) http...   Jan 12 2013, 20:14
- - greynol   Delay by a half sample: up-convert to a higher sam...   Jan 13 2013, 20:09
- - Woodinville   QUOTE (greynol @ Jan 13 2013, 11:09) Dela...   Jan 14 2013, 03:16
- - Ethan Winer   Oh, you math guys... Though I do understand up-sa...   Jan 15 2013, 21:42


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