Here are a couple of examples, both of which have to do with how the music was mixed and produced, not recorded (I think).
In some versions of Cannonball Adderleyās wonderful Somethinā Else (from the legendary Blue Note album of the same name) thereās a sudden, disconcerting reduction in the background hiss in one channel at the 6:40-minute mark. It continues until ca. 7 minutes. For those of us old enough to have grown up with cassette players, itās like someone depressed the Dolby noise reduction button and then released it 20 seconds later, albeit with the effect only being felt in one channel. The result is a muffled sound, with less air and sparkle. It upsets the recordingās balance and is intrusive enough, once youāve heard it, to ruin the piece of music. Donāt worry, though: itās not on every version that has been released. I havenāt checked enough versions yet to pin down the origin of it, and whether itās on the original LP, but I first noticed it on my CD copy, which I believe is the original CD release. Itās not on the more recent remastered version. Itās audible enough that you can hear it with most any headphone setup; itās easily discernible on youtube, although this example has it in the opposite channel to mine:
For the second example, on some versions of the classic song, Joshua Fit de Battle Of Jericho, from Grant Greenās outstanding Feelinā The Spirit, the tambourine is too prominent in the mixāto the point where it detracts from the rest of the music and becomes the only thing I notice. This isnāt just OCD on my part - or, at least not entirely - as itās not a problem on the remastered version (just the original digital release, I think). Arguably, my hearing is sensitive at this frequency, so it may not be such a problem for others. I hear it on my HD 6XX but itās unbearable on my brighter Clear and HD 800 (I know, I know, some of you are probably curling up in the fetal position, whimpering at the horrifying prospect of listening to tambourines on an HD 800 - sorry for frightening you).
PS: some of the Blue Note remastered Rudy Van Gelder editions have been celebrated, others criticized, by audiophiles; I donāt have the experience to comment, really, suffice to say that itās worth doing some homework before deciding whether to opt for the original or the remastered versions. And beware of some of Blue Noteās compilations; Iāve had one, on CD, that was markedly inferior to the original digital releases).
PPS: great idea for a thread! [edited for grammar and style]
) where I could actually hear the guitar amp distortion. It starts around 3ā15" and it should be hearable for 30s. I was wearing the HD600.