Maybe not new, but it is to me

I have done due diligence and searched via Google and this page![Itunesmusic|690x290] but still need advice. I have copied a few hundred CDs to an external drive (pointing my itunes library to that drive). They are in a folder called Music and show up just fine on my ipad and iphone. I am backing up said external drive to BackBlaze and may also copy over to a 2nd drive, just because. I am now deciding what to do with the existing itunes library on my Mac. As I was investigating, I discovered that I have a Music folder within iTunes (18G) and a Music folder within iTunes Media (29 gig). There are some duplicates of course. If I try to eliminate the duplicates before copying over to the external drive, which way should I go? I’ve posted pictures to illustrate–hope they’re clear.

Do you have a tool that can synchronize folders? Something like Chronosync or FreeFileSync? You could use that to make both folders the same and then delete the “iTunes Music” folder and keep the “Music” folder (since that’s the one that matches the default naming in iTunes).

Thanks for responding! I will look into that. For now, I’ve copied everything over to a partition on another drive (that is also backed up to BackBlaze).

It has been an education to learn about the structure of iTunes, which does seem somewhat convoluted. (I gather from perusing other threads that has been discussed before). This site was informative, even though I’m not sure I want to buy the product: https://www.fatcatsoftware.com/powertunes/Help/about%20itunes%20libraries%20and%20media%20folders.html

This, I believe, is the key piece of information on that page, particularly related to your duplication issues:

iTunes Media: The default folder that iTunes uses to store music for an iTunes library, alongside the iTunes library file. (iTunes 8 and earlier names the folder “iTunes Music” instead of “iTunes Media”)

Thanks. This task has certainly been an education. I understand (now) about iTunes media—just trying to figure out how I ended up with a folder that duplicates most of what I have. I may try the sync folder option or just weed out by hand.
This was an interesting article in my feed this a.m.: https://www.macworld.com/article/3397083/what-itunes-means-when-it-tells-you-deleted-songs-might-not-be-moved-to-the-trash.html
I’m not trashing (much) but it does contain some pretty good info about iTunes.