

I always assumed that the initial cutting of the record accounts for the variation in speed as the needle moves towards the center. If that’s the case, the information density would be relatively consisten, because the size of the bits of information would get smaller as the speed increases. Like a second of the song could be measured in radians, with the centimeters on the arc getting smaller. But I don’t actually know if that’s how it works.





So the arc speed increases as the radius decreases, both in cutting and reading.