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Topic: Why would a single track differ on a particular pressing? (Read 2041 times) previous topic - next topic
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Why would a single track differ on a particular pressing?

Occasionally I'll get rip results like the following where a single track is clearly different in a particular pressing or two...

Code: [Select]
[CUETools log; Date: 1/7/2016 7:54:04 PM; Version: 2.1.4]
Pregap length 00:00:32.
[CTDB TOCID: 2S94SdKa.nPBMgeX6LmsfmL_FSU-] found.
        [ CTDBID ] Status
        [aa51bc6f] (23/36) Accurately ripped
        [8eff92e4] (12/36) Differs in 11 samples @51:43:10
        [f8f6135c] (01/36) No match
Track | CTDB Status
  1   | (36/36) Accurately ripped
  2   | (35/36) Accurately ripped
  3   | (36/36) Accurately ripped
  4   | (36/36) Accurately ripped
  5   | (36/36) Accurately ripped
  6   | (23/36) Accurately ripped, or (12/36) differs in 11 samples @04:22:10
  7   | (36/36) Accurately ripped
  8   | (36/36) Accurately ripped
  9   | (36/36) Accurately ripped
[AccurateRip ID: 001b5dcb-00c84413-71124709] found.
Track   [  CRC   |   V2   ] Status
 01     [1e3acb53|2f18eb77] (008+009/192) Accurately ripped
 02     [726ce6c8|0cd1b181] (008+009/191) Accurately ripped
 03     [3f6a0341|6d6475ea] (008+009/195) Accurately ripped
 04     [71908d58|28619e12] (008+009/192) Accurately ripped
 05     [46b1f635|933d2c0a] (008+009/190) Accurately ripped
 06     [333a29cb|bd8ff138] (008+009/190) Accurately ripped
 07     [a8eb60da|faf64dc5] (008+009/191) Accurately ripped
 08     [a533a23a|c075a2ef] (008+009/193) Accurately ripped
 09     [2a1cb5be|1b617463] (008+009/185) Accurately ripped
Offsetted by -785:
 01     [3fd22276] (036/192) Accurately ripped
 02     [23007131] (035/191) Accurately ripped
 03     [d44a17b5] (036/195) Accurately ripped
 04     [4362c949] (036/192) Accurately ripped
 05     [0142042d] (036/190) Accurately ripped
 06     [9423dea2] (036/190) Accurately ripped
 07     [18917381] (035/191) Accurately ripped
 08     [941182f0] (035/193) Accurately ripped
 09     [7526c18e] (032/185) Accurately ripped
Offsetted by 1157:
 01     [b774e1a8] (002/192) Accurately ripped
 02     [f8af53a6] (002/191) Accurately ripped
 03     [b04ef6f6] (002/195) Accurately ripped
 04     [41bafa40] (002/192) Accurately ripped
 05     [42e5d88b] (002/190) Accurately ripped
 06     [edfc273d] (002/190) Accurately ripped
 07     [90ab2d6a] (002/191) Accurately ripped
 08     [504ac0c3] (002/193) Accurately ripped
 09     [d4c6962d] (002/185) Accurately ripped
Offsetted by 1848:
 01     [3ff20fb5] (003/192) Accurately ripped
 02     [1d3aa5ff] (003/191) Accurately ripped
 03     [f55833b8] (003/195) Accurately ripped
 04     [6b2d8e75] (003/192) Accurately ripped
 05     [b769d252] (003/190) Accurately ripped
 06     [9cacdcfd] (003/190) Accurately ripped
 07     [ab16b8bd] (003/191) Accurately ripped
 08     [860f2963] (003/193) Accurately ripped
 09     [9a530031] (003/185) Accurately ripped
Offsetted by -2133:
 01     [5e88a025] (000/192) No match (V2 was not tested)
 02     [db221d16] (000/191) No match (V2 was not tested)
 03     [0a234279] (000/195) No match (V2 was not tested)
 04     [63787515] (000/192) No match (V2 was not tested)
 05     [3a0d1616] (000/190) No match (V2 was not tested)
 06     [464785dd] (000/190) No match (V2 was not tested)
 07     [0baf235e] (000/191) No match (V2 was not tested)
 08     [38ebc000] (000/193) No match (V2 was not tested)
 09     [c7e75df1] (000/185) No match (V2 was not tested)
Offsetted by -2121:
 01     [23ca8640] (000/192) No match (V2 was not tested)
 02     [72c16d5c] (002/191) Accurately ripped
 03     [b3735f60] (002/195) Accurately ripped
 04     [4e85c9c0] (002/192) Accurately ripped
 05     [387ef054] (002/190) Accurately ripped
 06     [b53f28c0] (000/190) No match (V2 was not tested)
 07     [c8b1fa70] (002/191) Accurately ripped
 08     [c98b8db2] (002/193) Accurately ripped
 09     [24808b33] (002/185) Accurately ripped
Offsetted by -2118:
 01     [2068f091] (022/192) Accurately ripped
 02     [282fd7b6] (022/191) Accurately ripped
 03     [f70e5e2d] (022/195) Accurately ripped
 04     [0bff4f95] (022/192) Accurately ripped
 05     [5a9a39f3] (022/190) Accurately ripped
 06     [903a4fe0] (000/190) No match (V2 was not tested)
 07     [6e5eab0d] (022/191) Accurately ripped
 08     [f9ba40b0] (022/193) Accurately ripped
 09     [5db7b2dc] (020/185) Accurately ripped
Offsetted by -1454:
 01     [b8f07398] (009/192) Accurately ripped
 02     [e6fbbe79] (008/191) Accurately ripped
 03     [2ddc99ab] (009/195) Accurately ripped
 04     [34524f67] (007/192) Accurately ripped
 05     [cde4ccf3] (008/190) Accurately ripped
 06     [eae28efa] (000/190) No match (V2 was not tested)
 07     [96ad61a0] (008/191) Accurately ripped
 08     [83ae4f98] (008/193) Accurately ripped
 09     [5ae9a235] (008/185) Accurately ripped
Offsetted by -22:
 01     [1aaaf9dc] (002/192) Accurately ripped
 02     [64f7c2f5] (002/191) Accurately ripped
 03     [91ffd81b] (002/195) Accurately ripped
 04     [23efbb81] (002/192) Accurately ripped
 05     [adf700ea] (002/190) Accurately ripped
 06     [1e6cd095] (002/190) Accurately ripped
 07     [61b7b8ca] (002/191) Accurately ripped
 08     [1047c035] (002/193) Accurately ripped
 09     [930e0f41] (000/185) No match (V2 was not tested)

Track Peak [ CRC32  ] [W/O NULL] [  LOG   ]
 --   99.9 [AA0B353B] [FA922FDE]           
 01   99.9 [002AF0B9] [60D73E14]   CRC32   
 02   99.1 [EE2D143A] [A256B17A]   CRC32   
 03   92.3 [9BAD9FDE] [D0A137E0]   CRC32   
 04   87.0 [6DF58DED] [B7CEF1ED]   CRC32   
 05   88.9 [54B927F0] [37666037]   CRC32   
 06   97.5 [0464E096] [37DAFB03]   CRC32   
 07   97.9 [2BE9849A] [A801618A]   CRC32   
 08   61.6 [D7DEDC92] [6CDC503A]   CRC32   
 09   97.4 [97AD0243] [D91AFCAD]   CRC32 
In this case, it's clear that the -2118 and -1454 pressings had very slight differences in track 6, but that everything else was identical.

I'm not concerned about the quality of the rip - I can't hear anything happening there and clearly I got the same results as many others. I'm just curious about why this happens. Don't all pressings of a given CD use the same glass master? If not, why not? And in any case, wouldn't a manufacturing facility have checksumming tools similar to CTDB or AR that would alert them to differences in the CD? Do they just figure it's close enough and roll with it?

Just idly curious, and I'm sure someone here has a good answer.

Why would a single track differ on a particular pressing?

Reply #1 –
If they used the same glass master then they wouldn't be different pressings.

Why would a single track differ on a particular pressing?

Reply #2 –
The disc you have was not made directly from a glass master; it is made from a stamper. For a large run of CDs there will be a number of stampers made from a mother, maybe multiple mothers, which are copies of the glass master. Defects are inevitably introduced in all these molds and sometimes they can result in different audio.

Re: Why would a single track differ on a particular pressing?

Reply #3 –
Quote from: mjb2006 on
The disc you have was not made directly from a glass master; it is made from a stamper. For a large run of CDs there will be a number of stampers made from a mother, maybe multiple mothers, which are copies of the glass master. Defects are inevitably introduced in all these molds and sometimes they can result in different audio.
It seems extremely unlikely to me that a stamper could be defective in a way that resulted in incorrect but bit-identical output on 1/3 of the rips that made it into the CTDB.  I would expect damage on a stamper to either be error-corrected or get different results on different drives depending on how they deal with uncorrectable errors.