I have not experienced this, but the sound did go kinda flat...I replaced the ear tips and now have a better seal. Foams help a lot, for comfort and SQ.
I can recommend liberty 4nc. Compared to airpods 2 the sound is a bit more bassy, and the quality is just a tiny bit less. And the nc is not on par but still, the 4nc is great!
Don't know about other buds you mention. But definitely avoid 4nc. It's pretty decent sounding, but forget comfort. After 1-2 hours, your ear will sore badly. The chassis is bulky and protruding inside your ears.
I'm using liberty 5 currently and am pretty satisfied with it. Still comfortable to use after a few hours. But it's quite more expensive.
eartips arent the issue. Its the shell. Its bigger than average people ears. If you have big ears, i supposed you find it ok. But so many people report the same thing with 4nc. Its just not for long usage.
5prock3t
