What Emile Berliner perfected...to be exact...was the lateral-cut flat disc record/player...! Edison had apparently experimented with both, but being a perfectionist, figured out that the fidelity of a flat record would vary slightly between first and last turn of the spiral... while a cylinder record would play at the same rate from first to last turn (especially if the reproducer was driven across the cylinder by a feedscrew...!). The difference was that flat disc records could be stamped out in quantity, while cylinders were not moulded until early in the 20th century...!