Cassette to CD

There are mechanical limits to how quickly a disc can be spun. Beyond a certain rate of rotation, around 10000 RPM, centrifugal stress can cause the disc plastic to creep and possibly shatter. On the outer frontier of the CD disc, 10000 RPM limitation roughly equals to 52x speed, but on the inner crust only to 20x.

• But switching to CAV requires considerable changes in hardware design, so instead most drives cause the zoned constant linear velocity (Z-CLV) scheme

• This divides the disc into certain zones, each having its own disparate stabile linear velocity
• A Z-CLV recorder rated at "52X", for example, would write at 20X on the innermost zone and then progressively development the speed in several discrete steps up to 52X at the outer Cassette to CD rim.