Server is on Version 1.20.2.3402
Plex Web is Version 4.44.2
My Computer is a Mac on OSX 10.14
TLDR: After testing some sample files from my library, the best folder structure and file naming for good matching in my music library is:
Music / Album Artist / Album Artist - Album Title / 01 - SongName.ext
and for compilations
Music / Various Artists / Various Artists - Album Title / 01 - Track Artist - SongName.ext
This topic of naming and folder structures has been covered many times by the Plex Ninja’s and Moderators. In particular OttoKerner. Those posts helped me get on the right path to music library bliss and the basis for my test. Turns out, Otto’s way of naming and folders is still an excellent way to organize.
Love Plex. Love it more now with Plexamp V3. Because of Plexamp, I am slowly moving my music out of iTunes and into Plex and tagging with Musicbranz and re-ripping CDs when I need to.
I wanted to see what would happen if I put music files into my library with no meta tags in them. I created a sample library, imported some tracks with absolutely no meta tags and tested out some folder structures and naming conventions to see what would happen. I figured If I found a folder structure and naming convention that works without tags in the files I would be better off. And then adding tags to the files would only enhance the experience. Hopefully this post can shed some light on matching issues and help someone who is having matching issues or at the least a tested folder structure that works with pictures. Let’s have some fun. 
Regular Albums/CDs
I tested Plex with a Fresh CD. Put CD into my Mac and mounted to desktop:
Double Clicked on the CD open it up and reveal the tracks
Highlight / Copy and Paste some test files and named them slightly differently so I can see what happens with and without a dash between the number and songname.
For this test I was using the folder structure below:
Music / Artist / Album Title / 01 - SongName.ext
Music / Oasis / What’s The Story Morning Glory / 01 - SongName.aiff
Plex Music library results were bad. Ended up with a Various Artist entry and the tracks were messed up:
Now here is how Plex handles things when the folder structure is different. All I did was rename the folders to:
Music / Artist / Album Artist - Album Title / 01 - SongName.ext
Music / Oasis / Oasis - What’s The Story Morning Glory / 01 - SongName.ext
And the Results in Plex were much better:
I need to reiterate here. For this experiment, all I did was double click on the CD, selected all the aiff tracks on the CD, copied them to the folder structure above and named the audio files. I did not Rip them using any ripping software. I literally copy and pasted the files off the CD into my Plex Library.
I do not recommend putting your files into your library this way. There are many things wrong with this approach. I just wanted to show how the file structure and how you name your files is very important especially when you don’t have meta tags.
Compilation Discs:
I have many compilation/soundtrack discs in my collection so I had to test those also. For compilations/soundtracks I had to name the SongFiles a different way. For my test I used the soundtrack to Gone in 60 Seconds. I did the same copy and paste as with the other CD.
Music / Album Artist / Album Title / 01 - SongName.ext
Music / Various Artists / Gone in 60 Seconds / 01 - SongName.ext
And the results were bad.
So I renamed the folders and renamed the audio tracks a little bit:
Music / Album Artist / Album Artist - Album Title / 01 - Track Artist - SongName.ext
Music / Various Artists / Various Artists - Gone in 60 Seconds / 01 - The Cult - Painted on My Heart.aiff
And this was the result in Plex:
My conclusion after my test is that the best folder structure for me is:
Music / Album Artist / Album Artist - Album Title / 01 - SongName.ext
and for compilations/soundtracks
Music / Various Artists / Various Artists - Album Title / 01 - Track Artist - SongName.ext
File structures and namings have been covered many times before. The following post is very helpful and the basis for my testing: Proper naming for music files - first time setup for plex
Happy Plexing!!
