Ever since ancient times, scholars have puzzled over the reasons that some musical note combinations sound so sweet while others are just downright dreadful. The Greeks believed that simple ratios in the string lengths of musical instruments were the key, maintaining that the precise mathematical relationships endowed certain chords with a special, even divine, quality. Now, researchers think they may have gotten closer to the truth by studying the preferences of more than 250 college students from Minnesota to a variety of musical and nonmusical sounds.