@tonycollinet. I have started to think that I may be hearing differences in resistance. Solid metal connectors do seem to make a difference as well. I ran some off the cuff calculations and it did seem that solid metal connectors have significantly reduced resistance. I’m not sure how that would really matter at a single junction point but I have heard a big difference when swapping connectors and jacks over to solid metal or ultra thick platings.
When I’ve replaced wiring to tweeters, which usually have 18ga or smaller gauge, with air gapped 16 gauge, I do hear a big difference on the top end with just that wire swap. Frankly, it does not make sense to me, but maybe somehow resistance is at play here.