The use of different kinds of microphones and their placement around the studio was a crucial part of the recording process, and particular brands of microphone were used by engineers for their specific audio characteristics. The smooth-toned ribbon microphones developed by the RCA company in the 1930s were crucial to the "crooning" style perfected by Bing Crosby, and the famous Neumann U47 condenser microphone was one of the most widely used from the 1950s. This model is still widely regarded by audio professionals as one of the best microphones of its type ever made. Learning the correct placement of microphones was a major part of the training of young engineers, and many became extremely skilled in this craft. Well into the 1960s, in the classical field it was not uncommon for engineers to make high-quality orchestral recordings using only one or two microphones suspended above the orchestra. In the 1960s, engineers began experimenting with placing microphones much closer to instruments than had previously been the norm. The distinctive rasping tone of the horn sections on the Beatles recordings "Good Morning Good Morning" and "Lady Madonna" were achieved by having the saxophone players position their instruments so that microphones were virtually inside the mouth of the horn.