New TB W4-1337SDF vs. W4-1337SD?

Hi,

I was wondering if anybody here has gotten the opportunity to try the new, non-neodymium TangBand W4-1337SDF and compare it with the well-known neodymium SD-version?

Apparently, TangBand decided to make ferro-magnet versions of their popular drivers that previously were only available with a neodymium-motor, probably because of the inflation of neodymium-prices...

At the dutch "zelfbouwaudio.nl"-forum, there is a discussion about how big of an influence this has on the sound of the drivers, since they didn't just put a bigger ferro-magnet on them, but also changed the voice-coil to become approximately the same BL-value (Le=0.027mH instead of 0.015mH, x-max=2,5mm instead of 3mm with the same gap-height...).

Unfortunately, those new ferro-versions aren't available in this part of the world yet, so we can't compare ourselves (we have the neo-SD-version and even the older SA-version laying around)...

Isabelle