by Dorothy Caruso

At the Victor studio in Camden, New Jersey, he sang into a short square horn connected with the recording machine. The operator, who was working the machine behind a partition, made signs to him through a little window. No one was ever allowed to go behind that partition because it contained the secrets of the Victor Company. The musicians who accompanied Enrico sat on stools of graded heights at the back of the room. Their relative positions controlled the volume of sound, as there were no amplifiers in those days.

He began by singing with the orchestra. Then he told them any changes he wanted and sang the song again. "Good. Now we start," he said, and made a sign to the operator. When he had finished, the record was immediately played back to him and he discussed it with Mr. Child. Had it recorded well? Would the public like it? The record couldn't be replayed because it was made of wax and destroyed itself in the playing. Over and over he sang the same song. Sometimes a violin was too loud; then the violinist climbed down from his stool and retired to another farther back. If Enrico disliked the way a certain tone of his voice had registered, he insisted on making still another recording. At last, after two hours, a satisfactory record might be achieved. This was used to make the copper master record from which the black rubber ones would be stamped. Each time he went to Camden he sang at most only two or three songs, and although he longed to get back home he never rushed through the work or let anything pass that might be improved. Two days later when Mr Child brought samples of the finished recordings to New York, he and Enrico listened to them once more. This was the most important test of all, for both men had to agree on the perfection of every note before the record could be offered to the public. If they didn't agree, it was destroyed and Enrico had to return to Camden and do it all over again.

Once he had to sing "Cujus animan" from Rossini's Stabat Mater many times before he was satisfied with the recording. When at last it was finished, he drew a pearl stickpin from his tie and handed it to the exhausted trumpet player. "You merit reward," he said. "In the end I thought you would crack."
Dorothy Caruso, Enrico Caruso" His Life and Death
(New York: Simon & Schuster 1945), pp. 139-40