The Velvet Underground
Listen, I'm not here to tell my sophisticated readers anything they don't already know about the Velvets. They're either the third most important rock band of all time (Beatles, Stones) or the fourth (Stooges). If for some reason you don't already know all four of their albums by heart and need some advice on where to start, this is a pretty good overview. (Pretty darn well-written, too.) But let's assume you already know the name of the English professor who assigned Lou Reed the short story assignment that became the lyric for "The Gift," and bought a copy of the trashy paperback that inspired their name on eBay just to have it. Are you as cranky as I am that only one mix of The Velvet Underground, the radically quiet third album, is available on LP?
If my history doesn't here fail me, Lou Reed supervised an initial stereo mix of the record that emphasized the hushed, conversational quality of the songs even more so than the more widely available version. This is usually referred to as the "closet mix," since the instruments sound very muted relative to the vocals. MGM didn't like the mix and initiated a revision, although the original version made it out for the first pressing. Subsequent reissues have all followed the more traditional MGM mix. The "closet mix" finally made it to digital on the '95 Peel Slowly and See boxed set.
The songs on which the change is most obvious, although all the tunes are affected, are "Some Kinda Love" and "After Hours." The former is all rhythm guitar and floor tom on the MGM mix and barely anything besides vocal, lead guitar, and cowbell in the "closet" version. The latter has a pulsing electric bassline on the remix that can barely be heard in the original (although it's there if you know where to listen for it). In both cases, the "closet" versions are in Reed's opinion and mine the definitive mixes. In MGM's edits, the songs have a clear evolutionary connection to the simple electric rock songs the band had been playing since the beginning, while the Reed originals push the band to a new folk-inspired place that's been wildly influential since. To get a complete picture of how the Velvets became a very frequently repeated Brian Eno quote, the serious rock historian needs to hear the records as they were originally received.
Because I'm a sucker with a bit of a martyrdom complex, I keep buying new reissues of The Velvet Underground with no indication that they'll be any different than the four or five I already have, skipping right to the last track, and saying something ungentlemanly when that damn bass line starts in at full blast. If anyone even more obsessive than I knows of a reissue that has "closet" sound, I'd be obliged for the tip.
Ditto the 90's Iggy resuscitation of Raw Power.