" 

 == Lousy, not up to standard. == 

 Nothing substantial about vocal vibrato, which in ""Classical"" music is the real problem. 
 Opera fans are stupid freaks on it, and to me, it disfigures most opera into once in a while unlistenability. 
 Also, about instrumental vibrato, I have heard all my life that Joachim's Quartet was the first ensemble to play with constant vibrato."