A CD has a radius of 4.7 in (12 cm) for a playtime of 74 minutes because it is also the playtime of Beethoven’s 9th symphony.
This opus had to fit on a single disc by the wish of either Sony CEO‘s wife or conductor Herbert von Karajan… there are two versions of the story !
Here are the details for the version of the story with the CEO’s wife:
Sony’s CEO, Norio Oga, was conductor and cofounder of Sony together with Akio Morita. The length/speed of the 9th symphony varies depending on the conductor. 74 minutes is its length when the orchestra is conducted by Furtwangler.
