I have issues with fit - large single flange tips provide the best sound for me but they won't stay sealed, and for some odd reason I can't get bi and triflanges to seal no matter what I do. Large Comply foam tips seal perfectly, but I find them extremely muffled. I used some earplugs to make my own shorter foam tips where the driver is closer to the opening, but then they won't seal. All my IEMs fit the Comply T400/Nuforce NE-6/Sennheiser CX-xxx size opening. Can anyone point me toward a brand that offers particularly large single flange silicone tips? I think even a slightly larger diameter would be enough to create a perfect seal for my ears. The first person who can point me in the right direction gets dibs on my firstborn child.