Welcome to the forums.
When you posted about this before, you didn't just receive "some responses" you received correct responses. It's not clear what else you were expecting since you never followed up in that thread.
MC has a feature called Volume Leveling. Please read this article that you were referred to before, and use what it teaches you.
https://wiki.jriver.com/index.php/Volume_LevelingOthers told you what to do before, and that article explains it in detail. There's not much to tell beyond what's in that article. It has what you need, so I'm sure you'll find it helpful.
If after reading it, if you still have problems or don't understand, then post specific questions and describe exactly what you already tried and the results you did achieve.
I'd suggest continuing in your original thread, so that the history is there for people trying to help you, rather than starting new threads for the same thing.
FYI, Media Center is user supported software. Developers do read the forum, but the vast majority of questions are answered by other users, like myself. No one from JRiver is going to get on the phone with you. And the other users who do (or might) help you are doing it just to be nice. They're not obligated. If you want software with guaranteed phone support from the developer, you'll need to find a different program.
I hope this helps.