It is an interesting question, isn't it? Same thing with beauty. While we all agree on some "universal absolutes," it is hard to pin down the reasons why we all agree. Some research indicates beauty requires symmetry, and there is evidence that we like certain ratios too. Some have said that we pick up clues from shape and symmetry, ratios that indicate fitness to us. So maybe it's a little bit of a limbic system thing, essentially an emotional response.I think that probably applies to sound too. There are clues we pick up in the sound, and some are universal to all of us. But there are some things that each of us favor a little more than others. We all probably would dislike a grossly distorted signal, but when it gets closer to being accurate, one may prefer a little more bass, another likes a more pronounced midrange, things like that. We as engineers should probably strive to make our equipment as accurate as possible, but the subtle diferences will be what make some men prefer blondes and the others drawn to brunettes.