Keep in mind that under equal temperament, used ubiquitously today, all keys sound the same. The descriptions in the article probably only apply to a certain other tuning system. See https://en.wikipedia.org/wiki/Key_(music)#Key_coloration
Isn't equal temperament only possible for some instruments?
Obviously a string quartet doesn't normally play equal temperament, but they could if they wanted to, I think, if we ignore the playing of harmonics, which is a fairly unusual technique.