What is Involved in Remastering and Why?

[Togger]

The Beatles have remastered their music along with many other acts. Why is it done? Is it to improve the audio, or is it a way to change the songs, or eliminate mistakes, etc?

[nimrod]

It allows for enhanced clarity, letting listeners hear elements that were previously lost, such as subtle vocal harmonies, guitar lines, or percussion.
The 2009 remasters were crucial because they replaced the 1987 CD releases, which were regarded as poor-quality digital transfers. The 2009 project cleaned up "sonic grime" while keeping the music faithful to the original, intended sound.
Many early Beatles albums were intended to be heard in mono, with stereo mixes often treated as an afterthought in the 1960s. Remastering—and more recently, remixing by Giles Martin—aims to fix those early, hard-panned stereo mixes to create a more balanced, modern sound.

So yeah, it's done purely to improve audio.
To sum up...

Remastering (e.g., 2009): Cleans up the final audio product (like cleaning a painting) without changing the arrangement of the instruments.

Remixing (e.g., 2015-present): Goes back to the original multi-track tapes to rebalance instruments and voices, creating a brand new stereo or immersive soundscape.

[blmeanie]

In a lot of the remixing versions most recently Giles Martin moved elements around, forward and backwards too.  The bass parts moved forward in many songs and are more "in your face" now.  I am thinking of the Revolver remix which I leave the CD in my car cd player for a listen every now and then.

I have mixed feelings about the remixing, kind of the sentiment the Beatles had throughout their recording career- what we know, with any mistakes and less than perfectness is what we know.  Moving bass, vocals etc around might be "better" and also enjoyable but it is different than what we know and love.

One of the earlier versions of this difference is the Naked Let it Be vs original Phil Spector finished album

[Normandie]

To sum up...

Remastering (e.g., 2009): Cleans up the final audio product (like cleaning a painting) without changing the arrangement of the instruments.

Remixing (e.g., 2015-present): Goes back to the original multi-track tapes to rebalance instruments and voices, creating a brand new stereo or immersive soundscape.

I've said more than once on here that I'm not a musician and thus lack the insight most of you have in this respect. Thanks for this clarification, nimrod; I found it very helpful.