For years, I've been wanting to experiment with super tweeters, but knew they weren't well-received among audiophiles, and for good reason. You just can't plop a set of super tweeters on top of your speakers and expect them to sound good. They require simple crossovers tweaked for your taste. I purchased a pair of Fostex T96A super tweeters and followed this guy on YouTube who measured them and came up with the values for the capacitor and inductor:
https://www.youtube.com/watch?v=g7ieT0shO-w&t=665s This is a game-changer. There's a wonderful sparkle that was missing in my music and these super tweeters bring it in spades. The music floats, there's more attention paid to the singers (the accompaniment seemingly drifts to the background), and the detail in the highs is intense without being overly bright. Basically, there's more music on every CD I've never heard before. Lots of placement options to get the sound you want, and you can tweak the crossover endlessly.
A good super tweeter setup is analogous to the improvement gained by adding a subwoofer to fill in the low notes. I'm still experimenting with my temporary setup. I'll try adding some resistors to play around with loudness, but once I'm done, I suspect that super tweeters will be an essential part of my setup going forward. Of course, I'm open to any ideas or suggestions you may have as I continue down this road...