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Technically WAYYYY off base....

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In Reply to: Re: Back to analogue with Tony Faulkner posted by MusicLover on September 26, 2005 at 08:06:21:

So you've got a medium that works up to 22.05kHz. Yippee! Does your understanding of Nyquist extend to understanding that there must be NOTHING in the signal at 22.05kHz or above?
Now, show me a filter that has zero effect at 17kHz (the upper limit you arbitrarily defined) and yet has infinite cutoff at 22kHz. Can't be done. So, THEORETICALLY, there's no way to avoid screwing up the AUDIBLE signal with Redbook.
I know it's a troll, but I can't resist...
Peter

Follow Ups:

Re: Technically WAYYYY off base.... - MusicLover 13:59:29 09/26/05 (19)
I agree with you. Now you are addressing the problem of filters & ringing, etc. Problem was solved 10 year ago by Ed Meitner.
That's why I have a museatex bidat.
I'll ignore the sarcasm. I like to stick with facts and not waste ny time otherwise.
ML
- Still off base.... - Commuteman 14:21:41 09/26/05 (18)
  I tihnk sticking to facts is great. Feel free to provide some.
  Ed's a smart guy, but he certainly didn't "solve this problem 10 years ago"
  Of course, oversampling at the DA end will allow you to use a much slower filter with less audible impact, but you're still operating with 44kHz sample rate. I was talking about the AD problem.
  Please explain how you fix the encoding end. If Nyquist requires that there is zero content above half the sample frequency, what filter can you apply that has zero effect at 17kHz, but passes nothing at 22kHz?
  Remember, you were the one who said:
  (with my added emphasis)
  Sorry, you are erroenous. According to the Nyquist Shannon theorem, the sampling rate of redbook CD is sufficient to capture ALL information uto 22.05 KHZ . SInce most of us can hear only till 16-17 Khz, that;s way beyond what we need.
  This is simply TECHNICALLY wrong, UNLESS you can either:
  a)find a way to build an analog domain filter that has no impact in the audible band but is a brickwall at 22kHz, or
  b)sample at a much higher rate to allow less severe filtering, and then downconvert/filter in the digital domain to avoid time domain problems.
  AFAIK, a) is physically unrealizabe. b) sounds like an interesting approach (I have no idea if it's actually used), but it's still working around the fundamental fact that the 44kHz sampling is NOT enough.
  Now, how about some facts? Maybe I'm wrong.....
  Peter
  - about ADCs - Werner 22:33:13 09/26/05 (0)
    "b)sample at a much higher rate to allow less severe filtering, and then downconvert/filter in the digital domain to avoid time domain problems.
    AFAIK, a) is physically unrealizabe. b) sounds like an interesting approach (I have no idea if it's actually used), but it's still working around the fundamental fact that the 44kHz sampling is NOT enough."
    This is done in 99.99% of ADCs out there (*). These are delta-sigma ADCs oversampling with perhaps 64x, followed by ~21kHz anti-alias filtering and decimation. The filtering is of almost arbitrary high order and linear phase, and thus indeed does not impact anything below 20kHz.
    You are invited, though, to investigate what this filter does do to the signal, and where it differs from the low-pass characteristic of equivalent-bandwidth analogue tape.
    
    --
    Incidentally, recording suitable music without anti-alias filter doesn't sound half as bad as you may think.
    
    (* Peter Qvortrup holding the remaining 0.01%.)
  - Re: Still off base.... - MusicLover 14:47:55 09/26/05 (16)
    You are right, if music input devices (microphones, musical instruments outputs, etc) has significant energy above 20KHZ. My understanding is that microphones roll of very steeply after 20 KHZ ,and in some cases even before.
    Also, musical instruments don't output muchbeyond 20KHz. THis obviates the need for a very steep filter.
    This is what makes redbook CD practical and audibly indistinguishable (at least from a published study scientific perspective) from SACD, DSD or DVD-A.
    BTW, since this is a vinyl forum, i'd like to get back to point.
    Are you saying that your arguments in the earlier posts show that redbook CD is an INFERIOR medium for encoding the analog signal, as opposed to vinyl grooves? That the analog filters used audibly affect the encoding? for humans?
    ML
    - I think you miss one key point - Commuteman 15:32:59 09/26/05 (6)
      It doesn't really matter if there is or isn't any signal above 20kHz.
      You can't implement a 22kHz filter (needed for anti-aliasing) that doesn't effect frequencies much lower than that. It's one of those weird conceptual things, but even a 100kHz filter will have an effect way down at 20kHz (although it's small).
      I can recommend some things to read if you would like to learn more abou analog filters.
      To answer your last question: I believe that there is some digital encoding/decoding scheme that will beat vinyl in its traditional areas of strength, while building on CD's strengths, but 44.1/16 isn't it.
      Based on my experience and reading, it appears to be somewhere up above 96/24......
      I'm not anti-digital, but it's clear that "perfect sound forever" was a marketing lie. We just aren't there yet.
      Peter
      - Re: I think you miss one key point - MusicLover 15:37:18 09/26/05 (5)
        
        In Reply to: I think you miss one key point posted by Commuteman on September 26, 2005 at 15:32:59:
        
        OK. THanks.
        I disagree with you about the vinyl groove encoding scheme being superior to redbook, becuase, based on my understanding, vinyl groove encoding has much more distortion of the original waveform ( i remember reading somewhere it was 3-4%).
        Hence my conclusion, that while vinyl lovers may LIKE this, it's certaily inferior to redbook.
        AS i have said before, I like SET amps, but I accept that they suck performance wise.
        Anyways, thanks for your posts. I actually learned something, which is very very rare on the asylum.
        ML
        
        Well, even distortion isn't so clear :- - Commuteman 15:59:10 09/26/05 (4)
        
        In Reply to: Re: I think you miss one key point posted by MusicLover on September 26, 2005 at 15:37:18:
        
        Two thoughts about your distortion comment:
        (I'm not arguing for the sake of it; it's a fascinating subject)
        Don't downplay your love of SETs; they might actually be technically superior... :-)
        Vinyl's distortion characteristic is indeed similar to the SET in 2 important respects. First, the distortion tends to be dominated by low order harmonics, which are less audible than the high order distortion generated by amps that use feedback. Did you know that several percent of 2nd harmonic is virutally inaudible, while 1 percent 7th harmonic would sound terrible?
        Secondly, I would guess that the distortion decreases with signal level, so low-level musical details might actually be reproduced with v.v.v low distortion.
        Think about digital; it's the opposite. A digital system has the lowest distotion at maximum output. As the level goes down, the number of bits available also decreases, so the distortion goes up.
        That COULD mean that low-level musical details are actually reproduced with v.v. HIGH distortion.
        So, you see that this is an interesting technical onion that has layers of subtlety. Simplistic statements of clear superiority for digital are pretty risky...
        Peter
        
        Re: Well, even distortion isn't so clear :- - John Elison 17:47:54 09/27/05 (3)
        
        In Reply to: Well, even distortion isn't so clear :- posted by Commuteman on September 26, 2005 at 15:59:10:
        
        > > > Think about digital; it's the opposite. A digital system has the lowest distotion at maximum output.
        > > > As the level goes down, the number of bits available also decreases, so the distortion goes up.
        While this is true, distortion of any kind on �60-dB test signals for 16/44 digital is no higher than 0.15%. Furthermore, we now have high-resolution digital with 24-bit quantization. If musical peaks equal 24-bits, -60-dB must equal 14-bits. At 14-bits on a 24-Bit system, distortion of any kind will not exceed 0.015%
        On the other hand, the only test that matters is listening. If you have a digital recorder of reasonably high quality and you copy an LP, I don�t think you�ll be able to tell the difference between the digital copy and the LP.
        Best regards,
        John Elison
        
        Corrected: Yes, that is interesting... - Commuteman 10:50:19 09/28/05 (2)
        
        In Reply to: Re: Well, even distortion isn't so clear :- posted by John Elison on September 27, 2005 at 17:47:54:
        
        Just realized there was one important typo...corrected in bold
        First, though: remember that I am not anti-digital; I was simply responding to a massive over-simplification re the capabilities of 44.1/16. In one of the posts on this thread I did state that I thought something like 24-bit > 92kHz digital should be able to do everything vinyl can do....
        That said, I find it fascinating that so many people have reported better sound from CD copies of LP than from commercial CDs . One possibility is that the process of creating a commercial CD involves manipulation that creates the "CD signature", as opposed to the inherent AD-DA process itself.
        I have tried a few experiments using my Meridian processor that digitizes all incoming signals for processing and then recreates analog for output. Matching levels as closely as possible, I find that the feed that has been through AD-DA conversion is very slightly drier and flatter than the original. Less sense of space and reverb. Obviously, since this was not double-blind testing it's not proof of anything at all......
        So, back to the distortion question....
        Isn't -60dB roughly 10 bits down? That leaves 6 bits, right? 64 possible levels....
        I haven't tried looking at the distortion spectrum of a digital signal at this level, but I suspect it's pretty ugly, and composed of lots of high-order harmonics. (Unfortunately, my spectrum analyzer is in storage for another 6 months or so due to remodeling, so I can't try it right now..)
        I wonder what the distortion spectrum of your AT OC-9 would look like at an equivalent level? It's quite possible it's THD is WAY lower than 0.15%, and dominated by low order harmonics.
        At these levels, my money is on vinyl for lower distortion. The real question is how musically relevant this is....
        Interesting discussion!
        Peter
        
        Re: Corrected: Yes, that is interesting... - Werner 23:15:32 09/28/05 (0)
        
        In Reply to: Corrected: Yes, that is interesting... posted by Commuteman on September 28, 2005 at 10:50:19:
        
        "One possibility is that the process of creating a commercial CD involves manipulation that creates the "CD signature", "
        Actually it is the other way around: the process of creating a commercial LP involves manipulation that creates the "LP signature", whereas the CD is / can be a closer copy of the 2-track pre-master.
        Of course, nobody said that the LP and its limitations doesn't lead to a style of mastering that ultimately better suits the majority of domestic replay conditions (system, room, allowable levels).
        
        Re: Corrected: Yes, that is interesting... - John Elison 18:05:17 09/28/05 (0)
        
        In Reply to: Corrected: Yes, that is interesting... posted by Commuteman on September 28, 2005 at 10:50:19:
        
        Hi Peter,
        I have an interesting comparison for you to look at. Below are two spectrums, one from the OC0ML/II playing the lowest level 1000-Hz sine wave I could find on a test record, compared to a �60-dB signal from a Denon test CD. The interesting thing is that they are directly comparable because I have chosen a zero-dB reference for vinyl at the +18-dB level of the torture track on the Hi-Fi News test record. There are very few records that exceed that level, so I think it represents a good full-scale reference for vinyl. The nice thing about this level is that it falls exactly at �15-dB on the spectrum just like zero-dB full-scale for digital. Therefore, if you accept this level as full-scale for vinyl, you can compare the two graphs directly.
        One interesting thing to note is the excessive noise floor for vinyl that rises in the low frequencies due to RIAA playback equalization and arm/cartridge resonance. There might even be some turntable rumble involved, too, although I hope not. I have serious doubts that you would be able to hear anything below this noise because the spectrum analyzer cannot even identify anything.
        Another thing to note is that although the harmonic distortion is lower on vinyl for the �35-dB sine wave compared to that for the digital �60-dB sine wave, the actual level of harmonics in the digital graph are lower than those in the vinyl graph.
    - Way off base on alot of things - StylinLP 15:18:01 09/26/05 (8)
      You really need to put a stop to ignorant beleif that there is no audio beyond 20k or 22k or what ever. That discussion has been brought up and determined years ago. There IS audio way to to 50k. Ask any audio manufacturer of amps or cartridges. The idea that humans cannot hear beyond what every range your fixated on isnt the issue. Sound in those upper frequencies color and shape the sound at lower frequencies.
      That is a fact and verifiable to test. And has been done many times.
      Its been painfull to hear the unwashed masses brainwashed by the redbook cd lies over the years.
      *Analog fans may be blind-but digital fans are deaf*
      http://www.flickr.com/photos/82495693@N00/
      - If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... - John Elison 16:03:27 09/27/05 (6)
        
        In Reply to: Way off base on alot of things posted by StylinLP on September 26, 2005 at 15:18:01:
        
        ...that vinyl 2nd harmonic distortion from a 10-kHz fundamental exceeds 10%? Can you hear this terrible distortion that I can measure very easily at 20-kHz?
        Just curious!
        Thanks,
        John Elison
        
        Re: If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... - MusicLover 08:45:44 09/28/05 (0)
        
        In Reply to: If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... posted by John Elison on September 27, 2005 at 16:03:27:
        
        THanks John for adding your comments. So it seems that people who like vinyl LIKE the imperfections, which was the original comment that started this sub-thread. But to not admit it is imperfect is intellectually dishonest. Of course, we can argue about how we define "better" (is it something we LIKE better or something that is truer to the original signal) but that's another story.
        ML
        
        Re: If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... - StylinLP 16:27:43 09/27/05 (2)
        
        In Reply to: If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... posted by John Elison on September 27, 2005 at 16:03:27:
        
        Its a fact there is audio over 20k. Its a fact there is audio at 50k. The original question was weither someone can hear past 20k'ish
        Audio is not 1's and 0's its not yes or no. Its fluid sound that 16 bits cannot possible recreate 100% completely. What the digital poeple keep telling themselves is its enough for them.
        I can hear a CD player playing within 10 seconds just walking by a demo room at an audio shop. (not newer rock/pop stuff thou. Thats garbage to begin with)
        *Analog fans may be blind-but digital fans are deaf*
        http://www.flickr.com/photos/82495693@N00/
        
        You sound like some one that has never recorded your own CD-R from vinyl.... - John Elison 16:54:59 09/27/05 (1)
        
        In Reply to: Re: If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... posted by StylinLP on September 27, 2005 at 16:27:43:
        
        Or else you have never recorded vinyl on a high quality CD recorder.
        Perhaps you've never heard a CD played on a decent CD player.
        Oh, well!
        
        Sounds Like Music in Phx AZ carries Linn and other products *nt* - StylinLP 09:46:34 09/28/05 (0)
        
        In Reply to: You sound like some one that has never recorded your own CD-R from vinyl.... posted by John Elison on September 27, 2005 at 16:54:59:
        
        NT
        *Analog fans may be blind-but digital fans are deaf*
        http://www.flickr.com/photos/82495693@N00/
        
        You know 2nd harmonic is almost inaudible, right? - Commuteman 16:09:52 09/27/05 (1)
        
        In Reply to: If you think there is audio at and beyond 20-kHz, how do you resolve the fact.... posted by John Elison on September 27, 2005 at 16:03:27:
        
        It takes a lot of second order distortion to be heard; I seem to recall that the threshold is something like 2-3%.
        Of course 10% should be audible, or at least it will have an effect of some kind.....
        Peter
        
        Re: You know 2nd harmonic is almost inaudible, right? - John Elison 17:08:51 09/27/05 (0)
        
        In Reply to: You know 2nd harmonic is almost inaudible, right? posted by Commuteman on September 27, 2005 at 16:09:52:
        
        > > > Of course 10% should be audible, or at least it will have an effect of some kind.....
        Not if the fundamental is 10-kHz and the 2nd harmonic is at 20-kHz. I really don't think anyone can audibly detect distortion at 20-kHz, which would be 20-dB below the fundamental. Of course, I could be wrong.
        Anyway, that�s why I think that vinyl doesn�t sound so bad. Its greatest distortion is at high frequencies leaving only 1% to 3% at low frequencies.
        Best regards,
        John Elison
      - Re: Way off base on alot of things - HenryH 15:25:44 09/26/05 (0)
        
        In Reply to: Way off base on alot of things posted by StylinLP on September 26, 2005 at 15:18:01:
        
        He's clueless re harmonics of fundamental frequencies for starters.
        
        Henry
        Necessity is a mother . . .
I'd like to extend my apologies to everyone here also... - EdAInWestOC 13:15:47 09/26/05 (5)
Feeding a troll is subject to one demerit. Mark me up.
Ed

We don't shush around here! (Siegfried)
My system
- Re: I'd like to extend my apologies to everyone here also... - Bry 17:07:38 09/26/05 (0)
  I wonder if he's discovered that there are other forums to post in. Most of us here can compare CD's to LP's any time we want- something he refuses to do. So who's really more informed?
  -Bry
- Re: I'd like to extend my apologies to everyone here also... - HenryH 13:26:45 09/26/05 (3)
  Well, Ed, considering your contribution to all of us via the cartridge database (I access it almost daily), you are hereby officially forgiven.
  I didn't hear a "Harumpf" from that guy in the corner!
  
  Henry
  Necessity is a mother . . .
  - Harumpf - EdAInWestOC 13:29:31 09/26/05 (2)
    Harumpf...
    Watch your...
    
    We don't shush around here! (Siegfried)
    My system
    - Re: Harumpf - Fred J 05:02:02 09/27/05 (1)
      Ed- H
      How do you like your VDH 103 ? and how would you describe the differences between it and the standard or DL-103R, I'm very curious as I recently got a VDH DL-103 not even broken in yet, and have never owned a standard.
      Regards FredJ
      - My VDH 103D retains everything that made... - EdAInWestOC 05:14:34 09/27/05 (0)
        
        In Reply to: Re: Harumpf posted by Fred J on September 27, 2005 at 05:02:02:
        
        the original 103D so attractive and adds a degree of refinement and focus that pushes it up a level or two. Very recommended.
        Ed
        
        We don't shush around here! (Siegfried)
        My system

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