If you could look at a guitar string in slow motion, or frame-by-frame, you would see a primary frequency vibrating, but harmonics (multiples) of that frequency as well. It's the harmonics that give it the rich, full tone.
People who are having trouble with a skinny, fast flight string might want to give it a try, since most claim the higher pitched sound turns them off. It may be the harmonics they are objecting to and they might be able to quiet the string a lot by just adjusting the silencers. Works on my bows for me.