So, how do you test the diaphragm tension of an assembled capsule, or do you just listen empirically?
It always seems a little circumspect to me to peg difference down to just that. Small differences in the size of holes in the backplate for instance, etc., could seemingly make as much difference in end frequency response.
It also seems like low tension can be a bad thing... one of the first things to make a capsule sound bad, IMO, is low tension that starts to result in a capsule being overly sensitive to plosives.
So, has Sennheiser/Neumann improved things lately?
Extreme cases of diaphragm hypertension that I encountered in late 2017/18, and in the U67Reissue I tested and wrote about are getting rare. It's the average that still concerns me: too many people continue to send me current-issue capsules to reduce the tension back to 1960s level. It's time-consuming and not lucrative, but an interesting project I continue to refine and improve.