But it’s “The Beatles in Mono” box set that’s sparked the excitement of fans. The limited edition release has already sold out its pre-order copies at Amazon.com and other retailers, according to BeatleNews.com. “The new generation of CD buyers will probably be mystified by this mono and stereo thing,” Howlett said. “But the Beatles were recording at a time when there was this transition from mono, so they really only got to grips with stereo at the very end of their career.”

The mono box also contains its equivalent of “Past Masters,” which is a double CD called “Mono Masters” that collects up mono mixes of stray single and EP tracks. These are the mixes fans originally heard on their old records, which differ from the stereo versions. For example, Heatley said, “In the mono ‘Revolution’ there’s more distortion and it’s a harder kind of ‘Revolution.’”

Ramastered != Remixed

And, yes, I think I do want the stereo version, also because what she wants is the "complete" collection, which MONO box set is not.

It's still unclear to me if the stereo versions were remixed or only remastered. If they're just remastered, I recall the early albums having a really lousy stereo mix. Unless you really want to fade between John's guitar on the right and George's guitar on the left, I'd get the mono recordings.

They were talking about and demonstrating how they had managed to separate guitars from drums and the like digitally.

That was so that they could make Beatles Rock Band, which, not coincidentally, came out today too.

If they're just remastered, I recall the early albums having a really lousy stereo mix. Unless you really want to fade between John's guitar on the right and George's guitar on the left, I'd get the mono recordings.

This isn't really just for Beatles

But, it comes in two versions: mono e stereo. Why? What would you chose? Why the mono version costs more?

The Beatles were present during the mixing of the album in mono and the LP was originally released as such alongside a stereo mix prepared by Abbey Road engineers led by Geoff Emerick; the Beatles themselves did not attend the mixing of the stereo version. (The mono version is now out of print on vinyl, but was re-released on CD as part of the Beatles in Mono box set on 9 September 2009 worldwide) The two mixes are fundamentally different. For example, the stereo mix of "She's Leaving Home" was mixed at a slower speed than the original recording and therefore plays at a slower tempo and at a lower pitch than the original recording. Conversely, the mono version of "Lucy in the Sky with Diamonds" is considerably slower than the stereo version and features much heavier flanging and reverb effects. McCartney's yelling voice in the coda section of "Sgt. Pepper (Reprise)" (just before the segue into "A Day in the Life") can plainly be heard in the mono version, but is nearly inaudible in the stereo version. The mono version of the song also features drums that open with much more presence and force, as they are turned well up in the mix. Also in the stereo mix, the famous segue at the end of "Good Morning Good Morning" (the chicken-clucking sound which becomes a guitar noise) is timed differently and a crowd noise tape comes in later during the intro to "Sgt. Pepper (Reprise)".

Does anyone know if there exist multiple (discrete) track sources for the mono albums? I suspect that only the final mono masters exist and that's why we haven't seen a new stereo mix.