May i ask why, specifically, Rick Rubin? I don't know who that is, but whenever we finished mastering a new song, we had a series of "systems" we listened to it on. We went out to my dad's work van and listened there. We called up our friend with a street-comp sound system in his car, and listened in there (neighbors must have loved us!), and then a "cheap" boombox with large-ish speakers but cheap.

if it sounded "clean" on all 3, without the bass muffling everything, and the highs not hurting the eardrums, we called it "good" and released.

Working in the music industry and not being aware who Rick Rubin is… is a bit weird.