The story about jitter and CD Plants...?

Discussion in 'Mastering' started by Ammitsboel, Jun 18, 2004.

  1. Ammitsboel

    Ammitsboel Member

    Hi All,

    My burnings are 100% correct.
    This is tested with different CD's that all test's OK in Sequoia and afterwards has been digitally played into Sequoia and then make a perfect null when played phase inverted to the original signal.

    I've been pulling the master fader and trying to max amplify the signal, but there isn't any difference at all to the original signal.
    In fact Sequoia says that it can't normalize the signal simply because there arren't any signal.

    When i take this perfect burned CD and play it on my system i hear very small differences when comparing to the original CD, but the differences are there! As you all know this is jitter.

    I then called the local CD Plant to ask if they reclocked the signal from CDR audio to eliminate jitter and they asured me that they reclock the signal before they cut the glass master.
    The plant also told me that a CDR never could bee as good as a normal CD, there will always be jitter on the media no matter what burner or media you use.
    They also still accept Sony 1630 and Exabyte archives but not CD yellow book DDP 1 only DVD DDP 2.

    My question is: have you tested the CD plants near you to hear what plant makes the best CD's?
    If a CD plant doesn't reclock the incomming signal there will be jitter printed on the final CD... there must be some CD plants that doesn't do this and therefore makes a real crappy master CD.
    And what about those plants that has a crappy master clock?

    My problem is still that i can't give my customers a burned master to go home and listen to without jitter!! there will always be jitter no matter what burner or media i use.

    ....Or maybe my problem is that i have a "stereo" that plays the differences no matter how small they are?!? :?
    You could think that some mastering engineers must have really bad "stereo's" to make albums that has so big errors as some albums do....?!?

    Excuse my bad US english... I hope that someone will understant my words :lol:
    This is afterall one of the biggest problems in mastering!!

    Best Regards,
    Henrik
     
  2. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    You can choose a combination that will reduce the amount of jitter on the CDR. different media can produce different amount of jitter on the same burner. If you have pc, I think there is a program called speed 3.0 that can measure the amount of jitter on the disc. I think it's a free download.
     
  3. Ammitsboel

    Ammitsboel Member

    The speed program doesn't support plextor drives for the advarnced tests. What i can see in this program is just a perfect CD like it is in Sequoia.

    Michael can't you hear the jitter on your burned CDR's?

    Best Regards,
    Henrik
     
  4. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    Sometimes yes, most times no. Or at least I think it could be jitter. I run the digi output from the CD player to an apogee which cleans up any jitter in the signal. Most times if I hear a difference, it's the result of that piece of media. I run all my masters through a clover analyzer and measure the error rates. I have a jitter function on the analyzer but it's not hooked up to a scope. Usually a high Bler rate can be an indicator of heavy jitter on a disc. If I burn a master with an average bler of around 1 per sec, I can't hear a difference. If I use cheap media with an average bler of 40 per sec, I can hear it. Now all of these errors are completely recoverable but they are a symptom of probably a higher jitter rate on the disc. It manifests itself with a slightly collapsed image and the high end detail is less. So maybe your comparison is flawed in that it's not accurate as far as error rates in OTHER players. Maybe, maybe not. it's hard to tell without a full on analyzing of your disc by the manufacturer.

    It could also be your player and how it's filtering. Some players filter on the digital side and some on the analog side. Most on the digital side. When a player filters, the filter can cause overs and clip the output. There is also intersample peaking that can be occuring on the output which is when the digital signal is re-drawn, it can cause peaks above zero inbetween the area of samples if the level is at "0". different players react differently to these and can cause overs several db's above clipping. I believe the TC6000 has an option that calculates intersample peaks and limits accordingly.

    You know your samples are correct, so now you have to eliminate other variables to see what exactly is causing it and how you can minimize it. The plextor is a very good drive but a CD player isn't as good so my guess is it's the media... Maybe.
     
  5. Ammitsboel

    Ammitsboel Member

    I have an AudioNote CDT2 drive witch run into an AudioNote DAC5.
    I have no cleaning up, so if there's jitter I hear it.

    Michael i hear the same as you hear on very bad jittery CDR's. but on good CDR's i also hear a small difference with the same symptoms.
    When i play the CD in the CDT2 drive and record it in Sequoia it plays a perfect null when inverted agains the original.
    I don't think I will ever get rid of jitter on CDR's I can only try to make it as little as possible.

    This is not what i hear.
    I belive you are referring to the DAC filtering? My DAC is the only one in the world without digital or analog filter.

    If a CD player as my CDT2+DAC5 can play a CD in real time with less jitter than it would in the Plextor drive at same speed. Then my CDT2 must be a better drive than my Plextor.
    Michael, you must remember that a plextor drive is a "cheap" computer device that's made out of resonant materials, this also affects jitter.
    There is different media that can reduce jitter and i believe that I have found one of them.... but we still can't get rid of it can we?

    Have you tested a Plant CD against your burned Master?
    What sounds best?
    What my original question was: does the Plant get rid of the jitter?

    Best Regards,
    Henrik
     
  6. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    Depending on the plant, they have different jitter filters along with error correction. From what I can tell, there are 4 or 5 different kinds but I don't know what the differences are between them. Some manufactured CD's sound better than the CDR and some sound Worse and some the same. Why, I don't know. It could be many reasons. I believe it's the player and what it's laser is calibrated for. I find that Burners play CDR's better than non Burners. I have 4 players, 1 is a stand alone Denon player, 1 is a stand alone burner 1 is a pioneer elite and 1 is the Clover analyzer. When i get a tricky CDR that is having a problem playing something back on the Denon, I find that the burner can play it back. If that's having a problem then i stick it in the Clover and that can playback almost any condition CDR. Now when I have a really good cdr, I don't find a difference in the sound between them. When I have a bad CDR, Each player sounds a little different to me. i haven't tested these bad CD's to see what is causing the problem, which I should, but i'm usually in a session and don't want to waiste anyones time. They have high error counts but I don't know what the cause of the errors are.

    So to answer your question, the plants do have the equipment to correct problems but I don't know if they use them all the time.
     
  7. soundfreely

    soundfreely Guest

    Henrik,

    I am really curious about how this works. Forgive me if this is an ignorant question. How does the conversion work with no filtering at all? Is there filtering elsewhere in your chain? Or, am I misunderstanding this entirely?

    Just curious,
    Erik
     
  8. Ammitsboel

    Ammitsboel Member

    I experience many peoble especially circuit designers that questions a DAC with no filtering and thinks the carier is a signal that should be filteret out. To me this is peoble that doesn't listen to their work.
    But that's just my opinion.... and others too :lol:

    My listening tests has proven that a DAC with no filtering is more truth to the original signal than one with filters(digital or analog).
    You will have to use devices after the DAC that doesn't freak out when you hit their input with 44.1Khz at full output.... I have to add that very few devices freak out.

    Best Regards,
     
  9. kinetic

    kinetic Guest

    Just had to say....fascinating stuff :)
     

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