Personal experience with UM56:
I really only recommend for people that find great difficulty or imbalance with "star" tips. What I DIDN"T like about my perfect fitting UM56 custom tips is the following.
- They are uncomfortable. I went with vinyl. Never again. Silicone would be the way to go. After 20 min I feel the need to take them out for a break.
- The sound is very inclusive. Like wired to the brain. I don't like this.
- While the balance is perfection and all the detail is sharpened up, I prefer a more laid back larger soundstage type of listening experience. YMMV.
I'm nuts about the "star" tips. Great invention, well-deserved patent for Westone. I just wish they had one more size in between medium and large. Merely sm, med, lg still allows too much variance.
I do love the star tips, at least the short ones. They are way ahead of any other tips I've tried. The problem is my left canal has a very odd shape and it's very hard to get a secure fit with any tips, even Comply and Shure olives. The long tips give me a better fit but sound gets messed up and they make the housings stick out of my ears a little.