Thanks so much for your replies. I'm thinking of adding the entry level SVS subwoofer and a new Denon or Harman Kardon receiver to my old KG-4's. Would that make sense? I bought my KG-4's about 20 years ago and I like them but with all the technical innovations since then, I wasn't sure if they were obsolete and should be replaced with something more modern or add to them or what. I use them chiefly for listening to 2 channel stereo music. I've been using them with a Denon DRA-755 receiver from the same era. I want to upgrade my overall sound quality in a way that makes economic sense,(I'm a skinflint,) and still have the flexibility to expand into this modern home theater stuff later on. Sometimes I'll play music loud but mostly I just want a more highly detailed, 3 dimensional sound (whatever that means.) I have a fairly small living room in a mobile home. Aside from my modest financial resources, my biggest current problem is I'm going crosseyed reading about this stuff and trying to educate myself about modern home audio. And that brings me back to how very much I appreciate your input. Thanks.