List of famous crooners, with photos. Crooning is a 20th century style of singing made possible by the invention of microphones and amplifiers, which allowed the crooner to sing in a much softer, quieter, more intimate style. Its popularity peaked during the 1920's to 1950's with the advent of radio and electric recording allowing crooners to be heard by millions.Who are the best known crooners of all time? Crooners were almost by definition entirely male. As the decades passed, crooning began to fall out of fashion and was written off by many as a fad. It was ultimately dethroned by a new style of music in the 1950's, rock and roll. Today, modern crooners are categorized as "adult contemporary" or "easy listening".