Originally Posted by
schmidj
If the result was an accurate rip, no matter how many frames were re-ripped, the end result is that the checksum was identical to the results other(s) got ripping the same track. The probability of there being a difference in the bits is very low. I'm not sure of the actual number for Accuraterip but it is probably one chance out of millions.
The one caveat: If the results show an accurate rip of (1) and you securely ripped the same track before and (probably automatically) submitted the results to the acuraterip database, you might be comparing your new rip to your previously defective rip. (I think the automatic submission is monthly, so the rip you did five minutes ago isn't in the results yet.) Conversely, if your rip fails to match a single previous submitted checksum (accuraterip of (1)) It might be the previously submitted (by someone else)rip that is really bad and yours might be fine.
Once the accuraterip total is (2) or above, that means multiple copies of the same CD track had the same checksum, the chances of the track being inaccurate become very, very close to zero. (Although I've run into a couple of cases where there were bad pressing masters with errors that were sold to a lot of people. Your accuraterip match says your pressing has the same "built in" error the same as everyone else.
Now regarding the "Secure Warning" and "Insecure" tracks. In my mind, the goal should be that the ripped track sounds good to the listener, not that it has to be "bit perfect". Of course, OK is in the ear and brain of the beholder. Now if it comes up with a good accuraterip checksum you shouldn't worry, it will sound the same as the CD (if played at the same volume on the same reproduction system). But if it fails, it might save you some money and time if you listened to the "Secure Warning" and even "Insecure" tracks to see if you can hear an audible fault, and if that audible fault is bad enough to make you want to buy a replacement.
If you are of any age, you probably listened to a lot of vinyl, and possibly shellac 78's before you bought CDs. Did you rush out and buy another copy of the vinyl because it had another pop in one of the tracks? And all those cassettes with momentary dropouts where they were left parked in the middle in your hot car? Possibly if it developed a "skip", but I'd bet not for even quite a few pops and clicks. So if imperfect vinyl or cassette was OK, why isn't a slight imperfection in a ripped CD OK. Sure, if the track has repeated long dropouts, clicks or gets stuck, you won't want to listen to it, the same as if your vinyl got warped and the needle skips all over. I use dBpoweramp's ripper to find those and keep them out of my library. But, for me, unless it is annoyingly bad, I'd rather spend my money on a different CD, instead of another copy of the one I already have.
I recently acquired (for free, they were aimed for the dumpster) a box of close to 200 CDs, of genres I was interested in, but would be unlikely to buy new (even if they were still available). The only issue, the previous owner didn't take care of them, many had no jewel cases, and most of them were scratched, some badly, like someone had walked on them. (Why anyone would spend all that money to buy the CDs and then treat them like that blows my mind.) Anyway, I attempted to rip them. I set the allowable rerips at (I think ) 200, and turned off the deletion of error rips. I have several different make CD/DVD readers, and I know that one particular make (of which I own two) does much better than the others with scratched CDs, so I used those for the visibly badly scratched ones.
Many of those came up with rerips that resulted in tracks not matching the original checksum. Some had hundreds of reripped frames. Others came up "insecure" with unrecoverable errors. (Note that a track with rerips that doesn't match the original checksum is actually in error because at least one of the rerips falsely thought it was good, not uncommon when you set the allowable rerips high like the 200 I chose. You are playing a statistics "dice" game at that point, you'll eventually get a match of rerips even if it isn't the original bits.)
At first I listened to every track with rerips that didn't match the accuraterip checksum. Out of the several hundred I listened to, I never heard an audible error of a track marked secure but still didn't match the checksum. Of the tracks that were "Secure Warning" with rerips that it thought were OK, I think I heard a couple out of the several hundred which -might- have had a minor glitch. (I say "might", because given that these were old analog recordings, the original recordings might have had the same audio I thought was a glitch) Of the tracks that were "Insecure" (these are the ones that would have been automatically deleted if I hadn't shut off the "delete tracks with errors" option.) some, perhaps most of them had momentary audible "hits", mostly very brief dropouts. There were tracks with over 1000 reripped frames that sounded fine, two of the "Insecure" tracks had almost 3000 reripped frames.
This really trashed CD was one I really didn't care about but decided to rip as an experiment despite its condition. It took about 15 hours to get through all the rerips on the whole CD, but in the end all the tracks were listenable. I think three tracks had one or more of the very brief dropouts, the worst one had I think four or five.
There were a couple of CDs that just wouldn't play, one either had some form of copy protection or "bit rot" that gave long repeated dropouts when just playing every cut, and another badly damaged one I wanted that I spent several hours polishing with Brasso and a rag and finally got rid of enough scratches that I recovered all the tracks.
This is not to say that I've never had bad CDs out of the thousands in my collection. I have a large number of Caribbean CDs, many of which were duplicated as CDRs with poor quality control, and I've bought my share of duds, which I'm happy to keep off of my server. DBpoweramp has done a good job of finding those.
In the end I stopped bothering to listen to the "secure" ones on any of the box of scratched CDs, only listening to the "insecure" ones, and even then not finding any tracks that I decided were bad enough to delete.
So the final comment is that you might want to consider just listening to the tracks that fail the accuraterip checksum, you might decide to spend your money on something other than replacements.