CRC mismatches on same tracks across multiple copies of same new disc?
2017-06-25 17:33:58
Hello, this seemed like the best place to ask this: I've got a copy of Numero Group's Unwound box set What Was Wound --and on a few discs I consistently get CRC mismatches when doing Test+Copy. This seems extremely odd to me, especially when it seems to center on particular tracks. For example, Disc 5 I've got three copies of at this point (they sent a single replacement disc, followed by a second complete set) and tracks 12-18 always mismatch. For example, this is track 12 over multiple attempts [unfortunately, I'm not completely sure at what point I shift between each of three copies): Peak level 98.8 % Extraction speed 27.3 X Test CRC 173B9AC4 Copy CRC 9325E0F6 Track not present in AccurateRip database Copy OK ---2nd physical copy of disc--- Peak level 98.8 % Extraction speed 26.3 X Test CRC 1224A8DC Copy CRC 173B9AC4 Track not present in AccurateRip database Copy OK Peak level 98.8 % Extraction speed 15.9 X Test CRC 58D369A9 Copy CRC B9DA8865 Track not present in AccurateRip database Copy OK Peak level 98.8 % Extraction speed 27.3 X Test CRC 9325E0F6 Copy CRC FE4EB678 Track not present in AccurateRip database Copy OK ---3rd physical copy of disc--- Peak level 98.8 % Extraction speed 27.3 X Test CRC 5E1FED87 Copy CRC BCC5BA7D Track not present in AccurateRip database Copy OK Timing problem 0:02:34 Peak level 98.8 % Extraction speed 15.5 X Test CRC 182DD20D Copy CRC 0A6F8CB4 Track not present in AccurateRip database Copy finished That timing error that appears on the 3rd copy was completely new--hadn't seen any errors except the mismatches on the set until this one. A few CRCs repeat (albeit never in pairs). This particular disc actually skips about 33-50% of the time, while the other discs in the set with CRC mismatches (4/11 discs) I don't think I've noticed audible issues with when playing the original disc, and I mostly notice skips in fewer places than I'm seeing mismatches. A few odd tracks outside the consistently bad ones some times come out consistent across reads, but some never come out the same. I've ripped a good few hundred+ discs in this drive (LG GH24NSB0) and previously never had issues, outside of the odd used/OOP disc that either needed a cleaning or was truly hosed, nor had any issues with discs I've picked up after these. Am I crazy, or does this indicate a manufacturing issue? Certainly the skips (and at least one I hear consistently at roughly the same position on the same track of the same disc in all 3 copies I have of it--~2:20-2:30 on D5, T13) lean me that way, but I've just never seen this many errors, especially (semi-)consistently. And it's also a bit weird to me that the spot I just referenced sometimes plays fine on a variety of CD players (home and car). Sometimes it loops over a single moment in the "classic skip" fashion, and sometimes loops over 15-30s. It often seems that if I skip to the problem track, it plays fine, but if I let it play up to the track I get problems (but neither of those is 100% consistent, just a sort of overarching trend).