Based on many years working with Mass Spectrometer user contributed library data bases, here’s how I believe a database like AccurateRip works:
The assumption is that a non-bit-perfect rip is statistically not reproducible. As soon as AccurateRip gets the exact same bit pattern twice its logic is that it must be perfect. Given the size of a CD rip, this is statistically a valid assumption.
When a new unique rip is searched that is not in the AR data base, its reported as an error. When the exact same rip turns up a second time, it matches the first rip, is treated as accurate and added to the data base, so any subsequent search is labelled as a bit-perfect rip.
The Innuos system doesn’t need AR to confirm a bit perfect copy as it has the original CD to compare the rip against. If the two don’t match, it makes an appropriate entry into CD Rip History or quarantines the file, depending on which version of SW is used.
So here’s the question….if the Innuos ripper is producing non-accurate rips, how come it always gets it right the second time? Following the above logic the second rip is seen as correct because it matches the first rip and not because something about the rip has changed.
Here’s how you can test the above. Instead of deleting the first copy of the Innuos rip, leave it, rip the cd again and if you get a ‘duplicate’ error, it means that the Innuos SW is seeing the exact same rip twice i.e 2 bit perfect rips. If AR initially shows an error but passes the 2nd rip as bit-perfect it means that the AR database has now found a confirmation for the first rip (to which it assigned an error), added it to its data base and assigned a ‘pass’ .
In summary, Innuos compares its rip to the original while AR compares a new rip to the existing, user contributed library.
In a mass spectrometer, users can make their own spectral libraries using standards, or they can search user contributed libraries, produced on a variety of different instruments. The users own standards-based library is ALWAYS most accurate as it goes back to a certified standard and both standard and unknown are analysed on the same instrument. In essence Innuos use the same approach of comparing a rip to the original CD, so by definition the Innuos comparison is going to be more accurate.