A few words about the relevance of testing both front and rear sides of a dual-diaphragm, large condenser capsule, to select the better-sounding one for the front.
1. Even the best-made capsules with the tightest possible manufacturing tolerances have an audible difference between front and rear. But to my knowledge no one, not even Neumann, selects for front side preference.
2. In the best-made capsules, the audible differences between the sides will be small enough to recognize both sides as having similar timbres and personalities. But the expression of that character will be more or less strong: one side will always be more authoritative than the other in expressing that character.
3. Selecting the strongest side as front side can make a bigger difference in liking or not liking a microphone than all other features of that microphone combined.
4. Trust your ears: you will be able to tell the difference. Even if the difference is small, you can be confident in your choice, once you tried both sides.
