What changed between the Arri BL2 and BL3 to make the lens blimp unnecessary?

[Geffen Avraham]

In the BL1 and BL2, the hard lens mount was a source for sound vibrations to escape the blimped body, and a lens blimp was needed.

By the BL3 and Bl4, it wasn't. What changed?

[Aapo Lettinen]

18 minutes ago, Geffen Avraham said:

In the BL1 and BL2, the hard lens mount was a source for sound vibrations to escape the blimped body, and a lens blimp was needed.

By the BL3 and Bl4, it wasn't. What changed?

the lens mount was changed to PL mount and by my knowledge they changed how the movement and lens mount are mounted on the main body. There is vibration isolation between the movement and lens mount so the vibrations are not projected through the lens making sound.

The old BL1 and BL2 used Arri Bayonet and needed lens blimp for the lens mount not isolated the same way than BL3 and BL4

[Fabian Schreyer]

The first batch of BL3 cameras did not have PL mount.