Will Subwoofer Help?

Probably the reason some stuff sounds bloated and boomy on the bottom end is the source material. Nothing to do with your system. The best system cannot make poor source material sound good. This is one reason why audiophiles waste a lot of money. They think they can improve the sound of a sh!tty recording. They can't. Unless they get into their time machine and go back and improve the original recording and mastering.

powered subs do take over the heavy lifting from the amp and speakers but in your case I don’t think you need one. From your description of your regular speakers I’m thinking they have good response down to 20 hz. You probably don’t need a sub and if you run the main speakers full range with a sub the sound is going to be way too bass-heavy. Also the sub and the mains will be reproducing the same low frequencies which is a no-no. If you get a sub you want to set a crossover between it and the mains at about 60 0r 80 hz.

for some real interesting reading on wikipedia type a search for "Dyatlov Pass incident" and read the article.