Submarine remastering: The secret, inferior version of Pearl Jam's "Vs."

Despite no documentation, there are at least two separate masterings of Pearl Jam's LP "Vs." floating around. One of them is clearly inferior to the other. Simply put, one of the masters was highpassed at around 40hz, with the resulting digital overs clipped, to generate the new master. Such a master suffers from both reduced bass and greater amounts of clipping.

I haven't seen any documentation, either online or on the printed packaging of "Vs." that I just saw at the store, to suggest that this remaster ever took place. Therefore I'll dub it a "submarine remaster". Just like in the bad old days of vinyl, when different pressings of the same record might have used vastly different mastering practices with their only documentation being their dead wax info, a submarine CD remaster may be considerably different from the original, with a different pressing indicated by a different ISRC.

Here's a plot of the eq differences between the two masterings, measured from the first 60 seconds of "Animal". The bottom axis is frequency in hz; the side axis is attenuation in db. A 1-second window was used with a 50% overlap. At 20hz the masterings differ by 12db, so this ought to be quite audible with a suitably good system.

Here's a zoom-in comparison of the waveforms, illustrating the two stages of clipping in one of the masterings, where one of the clipping stages matches the clipping found in the other mastering. This may not be audible, but it certainly could have been avoided and is unfortunate.

Unfortunately, I don't have ISRCs for the two pressings, but I am 95% certain that the bassier/less clipped master is from the original 1993 CD, and the newer/more distorted master is from the 2004 Sony reissue. (Update: After speaking with greynol further and comparing notes, we now have no idea exactly which master corresponds to which release. Both of our CDs predate 2004, but his has the two clipping slopes identified in the red plot above, while my CD has the single clipping slope of the black plot. Comments here affected by this have been struck.)

The pressings both ReplayGain to the same value - no gain or added dynamic range compression was applied. I don't know which version is used for iTunes/Amazon music downloads. Looking at a copy of the Vs. CD at a store, there is no visual indication on the outside of the case that it is either the 1993 or the 2004 pressing.

So what's my point? Besides being a very odd example of a "remaster", and one that's worth posting about, the circumstances surrounding this release suggest that no notice may be given if a newer pressing of an album is a remaster. Those looking for the "authentic" version of Vs., and certainly the one with the most bass, should almost certainly look towards the original 1993 CD.

More generally, if you're looking for an "authoritative" master of a back catalog CD, it may still be important to buy the original pressing, even if a newer pressing does not advertise any remastering. Or, if the newer pressing surreptitiously corrected a flaw in the original, vice versa. But if the CRCs match between two pressings, then the newer pressing matches the old one exactly. And If they don't, it's still possible the differences are trivial, like a difference in track offsets. A thorough analysis must be done to concretely identify the differences between each master. Got that?

Thanks to greynol for the heads up.

Update: See above for new notes on pre-2004 pressings.