Beatles’ story it’s not just the one of a rock band: for more than a reason it’s the story of contemporary music itself and of its technical progress.
The years of activity of the band saw an autentic revolution of studio recording technics, passing soon from primitive overdubbing methods to modern multitrack machines.

When the four first came to studio, George Martin could show them all marvellous possibilities of technology of that time, which allowed to record a song using two different tracks.
Being so, they usually divided their work recording a live musical base first, and all voices on the second track later. There were also some overdubs, but it took a method so complicated that they used it only for very short parts: there was to record a new take listening to the one before, and then put both takes over a third one, trying to synchronize them exactly.

All early Beatles’ records were made this way, which explains also why the stereo version of those songs has all instruments on a channell and all voices on the other.

A great change happened when new four-track recorders were adopted in 1964 (maybe the first song recorded on it was “I Want to Hold your Hand”). Now they could have fun using more overdubs with much more cure for details. Think about “Help!”: if you listen to the basic recording made on the first track, you can notice the lack of the country guitar phrase at the end of every chorus (for ex. before the first verse “when I was younger etc.”). That phrase was recorded later on a different track, allowing Harrison to play concentrated and eventually redoing it in case of mistakes.

Working on “Rubber Soul” in 1965, for the first time the whole 4-tracks technique was fully used to create new sounds: in the next two years all this would improve to new and revolutionary possibilities. Paul McCartney, for example, soon wanted his bass part to be recorded later on another track, so to allow a better mixing (improvement of bass sound was one the Beatles’ main problems in 1966-67). They usually did so: the band recorded a basic track, with just essential instruments: drum, bass (sometimes), rhythm guitar, keyboards and a lead voice to be cancelled later. From now on they started overdubbing, trying and experimenting several versions. If all of four tracks were full and song was not finished yet, they bounced two tracks down, trying to balance the two volumes correctly (it would not be possible fix such a mistake during mixing). And so and so until the end: that’s the way “Sgt. Pepper” was recorded.

But the Beatles, eternally unsatisfied, soon became bored and frustrated about only four tracks, also since they knew the were eight-tracks recorders. That caused some problems with the EMI, which policy was not to switch to new machines before testing them for a long time.
That’s why the earliest eight-tracks sessions of the Beatles took place not at Abbey Road Studios, but at indipendent Trident Studios, while working on White Album. The first song to be recorded this way was “Hey Jude” in 1968; some weeks later, the new technology was used also for some strange solutions: for example, the drum parts of “Back in the USSR” and “Deat Prudence”, recorded while Ringo Starr was out of the band, were played by all three other ones, putting together different parts from different tracks.

Now possibilites were enormous, and it has to be said that they used them mainly for their maniacal cure for details, which is what most of all characterizes their best records. The Beatles went on recording a base track all together; the other seven ones, beside vocals, were filled sometimes with apparently minimal but essential parts. The better clue is “Abbey Road”, the last album to be recorded, which after the live experiment of “Get Back” put Beatles back to work with George Martin: it’s a masterpiece of precision, smartness and cure for details.

However it was hard work the main difference between the Beatles and the others. You cannot become a Beatle by chance.