Considering this, what makes a piece of music sound good?
Beating occurs when two sounds are close but not identical in frequency. The researchers' results show that musical chords sound good or bad mostly depending on whether the notes being played produce frequencies that are harmonically related or not. Beating didn't turn out to be as important.
Beside above, what makes music bad? It's got to be something that people really know to be a contender for worst song ever and has to be a song that has some lyric element that is bad. It has to be just either trite, obvious lyrics, something that's offensive or something that just is overly maudlin or sentimental in its lyrics.
Secondly, why is music so powerful?
Music is a language of emotion in that it can represent different feelings and barge into the soul with no boundaries or limitations. People are always challenged by the fact that “no one understands them” or know how they “really feel”, so they turn to music. Music also has the capacity to imitate emotions.
Why do 7th chords sound so good?
The chord is really cool because it has two of the most consonant intervals (a major third and a perfect fifth) and also has one of the most dissonant intervals, the major seventh. So it's sort of in limbo wanting resolution while being resolved (if we're talking in intervals.)