I tested my Symbio Wide Bores on several IEMs, even tried them on some of a friend of mine's IEM's. I had to keep trying them because I couldn't believe how good they actually were. They allow all of the mids and highs through due to the wide bore, but they seal the best out of any tip I've tried and bring great low end even to IEMs that were lacking. I had recently bought some FiiO F1's and wasn't a fan due to no real low end. The Symbios changed my whole opinion on the F1. The lows they were able to achieve were phenomenal. Now, with the FiiO F1's and the Symbio tips together, I finally have a replacement to my beloved cheapo Sony's that died trying to be ice cubes in my lemonade, lol. With the Icarus III/Symbio combo, I was forced to EQ some of the Bass out, there was so much air pressure moving that I felt it tickling my ear drum. (Definitely not good for you
@Karendar, with your Tinnitus). The foam inside these tips take a minute to warm up, but as they sit in your ear they "melt" into the shape of your ear canal giving a great seal without any pressure to cause any inner ear pain. Totally worth the wait for them to arrive from Hungary, and I'm going to place another order to have more on hand. For anyone interested in buying some, they are a bit on the big side, so order one size smaller than you would on most tips.