Lathed v Standard CDs - listen and decide

Discussion in 'Hi-Fi and General Audio' started by RobHolt, Jul 26, 2009.

?

I prefer

  1. Track A

    25.0%
  2. Track B

    25.0%
  3. I cannot detect any difference

    50.0%
  1. RobHolt

    YNMOAN Trade - AudioFlat

    Joined:
    Jul 16, 2007
    Messages:
    674
    Likes Received:
    0
    I doubt that many more people are likely to vote now. Eleven have now voted – even if that number was to be doubled it would mean next to nothing in a statistical sense.

    Perhaps I am biased though as I want to know which was which.
     
    YNMOAN, Aug 5, 2009
    #41
    1. Advertisements

  2. RobHolt

    DavidF

    Joined:
    Mar 31, 2006
    Messages:
    3,296
    Likes Received:
    1
    Location:
    Shropshire
    I guess you lot are playing striaght off squeeze boxes??
     
    DavidF, Aug 5, 2009
    #42
    1. Advertisements

  3. RobHolt

    RobHolt Moderator

    Joined:
    Oct 24, 2004
    Messages:
    4,123
    Likes Received:
    5
    Ok then -

    A - Standard CDR
    B - Lathed CDR.
     
    RobHolt, Aug 5, 2009
    #43
  4. RobHolt

    Graffoeman

    Joined:
    May 29, 2008
    Messages:
    130
    Likes Received:
    0
    Many thanks to Rob and Lee - that certainly was an interesting exercise. I don't suppose it was conclusive in any way but it was great fun! :cool:

    And yes, David, I did do the comparison straight off my Squeezebox. :D
     
    Graffoeman, Aug 5, 2009
    #44
  5. RobHolt

    DavidF

    Joined:
    Mar 31, 2006
    Messages:
    3,296
    Likes Received:
    1
    Location:
    Shropshire

    They are not as good as cd players any way so I haven't missed any thing!


    ;)
     
    DavidF, Aug 5, 2009
    #45
  6. RobHolt

    zanash

    Joined:
    Jun 20, 2003
    Messages:
    3,826
    Likes Received:
    1
    Location:
    Notts.
    absolutly no meaningful conclusion can possibly be drawn from this test with such a small sample ....thats regardless of result...........

    let me poss a few question again ...

    how can you prove to me sample A is the lathed disc ?....
    how do we know that sample b[orA] has not been altered in the in away that the other has not ?
    where are the controls samples .... ?
    no explanation as to why one sample is louder than the other ....or is it only me thats had a duff download ?
    were the cdr's cut before or after the audio track was coppied ?
    why did you need to use cdr's ?
    why not use to cd's as the lathe was designed for ....

    I've said in previous threads that cdr's just don't seem to have the same effect ......therefore I struggle to understand why you used them .....
    where as you could have niped down to tesco and bought two brand new identical cd's.....


    At the cost of being repetitive ....if anyone wants to send me a pair of disc so they can carry out a "proper" listening test .... then pm me

    there will be no cost other than the return postage .....

    This is not being negative or paranoid ...its just there are too many variables and loose ends to make this anything other than flawed however lord able an attempt.
     
    zanash, Aug 5, 2009
    #46
  7. RobHolt

    Tenson Moderator

    Joined:
    Nov 12, 2003
    Messages:
    5,947
    Likes Received:
    1
    Location:
    Kent, UK
    I think you missed the point entirely Zanash.

    Still, at least you make the forum a more interesting place!
     
    Tenson, Aug 5, 2009
    #47
  8. RobHolt

    sq225917 Exposer of Foo

    Joined:
    Jan 11, 2007
    Messages:
    1,514
    Likes Received:
    0
    Oh **** off Pete, stop being a dick..

    What this test shows me is that I can still recognise a lathed cd. I already knew that many people have shit systems and can't hear subtle differences if they don't actually know what they should hear as a a change.

    Nothing new there, i doubt I would have picked with such certainty had i not heard a lathed cd before.
     
    sq225917, Aug 5, 2009
    #48
  9. RobHolt

    YNMOAN Trade - AudioFlat

    Joined:
    Jul 16, 2007
    Messages:
    674
    Likes Received:
    0
    One isn't louder than the other and you can't get a 'duff' download in that sense (if it has downloaded and plays then it is not going to download any better) - draw your own conclusions.
     
    YNMOAN, Aug 5, 2009
    #49
  10. RobHolt

    Tenson Moderator

    Joined:
    Nov 12, 2003
    Messages:
    5,947
    Likes Received:
    1
    Location:
    Kent, UK
    Okay here is something interesting. This is a 'null test' for the two samples. That means what is here is only the difference between them.

    I took both tracks, aligned them sample for sample with a distinctive point in each track, inverted the polarity of one and overlayed it with the other. If both tracks are exactly the same they will cancel out, if they are not the same then the difference between them will remain.

    [​IMG]

    Interestingly there IS a difference! However it is very abrupt, either there is a difference or not. I guess this is evidence of error correction either recovering the data fully or not.

    So, is the lathed CD reading more accurately? Rob and I did a few further tests. The conclusion was that the CD player did not read CDs exactly the same each time they are played, and the errors were sometimes in differnt places and lengths so this suggests it is not errors in the recording of the CD-R. But no, the lathed one didn't seem to be any more reliable!

    To find out more about this I should do more tests, but to be honest I can't be bothered! I'm pretty certain ripping a CD with Exact Audio Copy on the computer would give repeatable reliable data, if you care about it!
     
    Last edited by a moderator: Aug 5, 2009
    Tenson, Aug 5, 2009
    #50
  11. RobHolt

    RobHolt Moderator

    Joined:
    Oct 24, 2004
    Messages:
    4,123
    Likes Received:
    5
    Pete,

    Essentially you are doubting my integrity by suggesting that these files might be doctored in some way.

    I can only assume this is because you didn't like the result, which is very poor form IMO.
    Forum members can form their own conclusions.

    We'll do cables next, so do get working on your next set of objections.

    Anyway, now that silly distraction is dealt with, FWIW I slightly preferred B, the lathed disc as to me it did sound a tiny bit easier on the ear and less strident.
    Might have been the effect of lathing or perhaps just the way the CD transport responded to the two discs in a more random way. Of course my listening test was sighted which should be taken into account.

    I found it a useful exercise since I didn't expect to detect any difference at all.
     
    RobHolt, Aug 5, 2009
    #51
  12. RobHolt

    RobHolt Moderator

    Joined:
    Oct 24, 2004
    Messages:
    4,123
    Likes Received:
    5
    Interesting that those differences don't manifest themselves as obvious problems, ie ticks, skips or glitches. Just a slightly different sound it seems.
     
    RobHolt, Aug 5, 2009
    #52
  13. RobHolt

    lbr monkey boy

    Joined:
    Jul 13, 2004
    Messages:
    837
    Likes Received:
    0
    Location:
    In a happy place
    bugger bugger, bugger. Should have been a spoiler warning!
     
    lbr, Aug 5, 2009
    #53
  14. RobHolt

    scott_01

    Joined:
    Sep 1, 2005
    Messages:
    433
    Likes Received:
    0
    I thought this was useful too. I did hear a difference and indeed plumped for the 'wrong' one. Preferring A over B.

    I heard the Lathe demoed at Coherent a couple of years ago with 3 different CDs. FWIW I remember the Doves 'last broadcast' being the most noticeably improved item; there were differences of varying degrees with each CD. Apparently it makes sod all difference to some recordings.

    Don't have a problem with the methodology at all. Glad I heard some difference, funny that it's the reverse of others, maybe my ears are out of phase? :D
     
    scott_01, Aug 5, 2009
    #54
  15. RobHolt

    felix part-time Horta

    Joined:
    Dec 13, 2003
    Messages:
    757
    Likes Received:
    1
    Location:
    dead
    Actually I would say 'not' I can think of several phenomena - or , more accurately, the same problem, and half a dozen places it could be manifest - that would lead to this, even assuming a perfect data 'read' in both cases. A noisy immersion thermostat could do it ;)
     
    felix, Aug 6, 2009
    #55
  16. RobHolt

    markabuckley

    Joined:
    Nov 26, 2004
    Messages:
    90
    Likes Received:
    0
    from a mathematic point of view the results are now very interesting - a perfect random distribution ?
     
    markabuckley, Aug 9, 2009
    #56
  17. RobHolt

    RobHolt Moderator

    Joined:
    Oct 24, 2004
    Messages:
    4,123
    Likes Received:
    5
    More voters would have been nice.
    Still, we've got cables next which always stirs up much interest and excitement :)
     
    RobHolt, Aug 9, 2009
    #57
  18. RobHolt

    DavidF

    Joined:
    Mar 31, 2006
    Messages:
    3,296
    Likes Received:
    1
    Location:
    Shropshire


    I don't think so.


    :SLEEP:
     
    DavidF, Aug 10, 2009
    #58
  19. RobHolt

    RobHolt Moderator

    Joined:
    Oct 24, 2004
    Messages:
    4,123
    Likes Received:
    5
    Ah David, this one will.

    I guarantee to keep you entertained :)
     
    RobHolt, Aug 10, 2009
    #59
  20. RobHolt

    sq225917 Exposer of Foo

    Joined:
    Jan 11, 2007
    Messages:
    1,514
    Likes Received:
    0
    So, do the test again but this time split the test up into those who failed and those who succeeded and see if we fall into the same groups again.
     
    sq225917, Aug 11, 2009
    #60
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.