I've used an online version of Spleeter or similar and it's okay but the caveats as mentioned are many & various.

I'm often amazed and amused at the need to "remaster" stuff.
I wonder whether the music in question was "mastered" by an M.E. or "mastered" as in run through some software without the ears & knowledge to support it, (ears being the most important), or is just the stereo mix.
If the master was bad going back to the, probably stereo, mix file makes sense but a lot of folk are simply throwing new software over an existing master. That's be extramaster/overmaster/or something wouldn't it?

The oft expressed desire for the one button magic leads, quite often, to the hit n miss of up n down load "mastering" offered by Soundcloud and other "I.A." enabled mobs.

Here's a useful option:
This person will, as a free sample, properly master an uploaded song and send a MP3 of the completed job. If you like the results you can pay for the full definition audio file and you're away. If you don't like it you keep the MP3 no fee.
The difference is that there's a bloke at the otehr end who uses his ears, decides what needs to be done and how, tweaks according to his skill set and experience and yes you can include a reference track as guidance.
https://www.presentdayproduction.com/mastering



Last edited by rayc; 01/19/22 01:54 PM.
Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe