It's very annoying that all my top iems have bad fit...
What, specifically, is not fitting?
There’s many things you can do to help an earphone fit better.
1. Sometimes, all it takes are different eartips. Perhaps one size larger, one size smaller, a slightly longer tip, a slightly shorter tip, etc. You can also try specialty tips, such as FlipTips, SpinFits, foam tips, Xmas trees, etc.
2. I will also mention 100% custom eartips. You can have a professional pair made from a company like PureTone (in the UK) or Advanced (
https://www.adv-sound.com/products/eartune-fidelity-custom-fit-eartips), or you can make them yourself (like I did with the KZ ED9 below).
3. The problem could be the ear guides of the cable. I wear glasses, and often ear guides get in the way. Or some ear guides are way too thick. Others are formed with too much curve or at a funny angle, and the guides can actually cause the earphone to slowly work loose.
4. Sticking with the cable points, the plug of the cable could be a problem. Some earphones come with straight plugs, but need angled ones. Others come with angled ones, but really need straight ones. Below shows a perfect example of an earphone that came with straight plugs but should have come with angled plugs. It’s just laziness in the part of the manufacturer. Look at how the fit is affected with the wrong plugs:
5. Something that’s often overlooked, but dirty ear canals can cause fit issues. Too much wax buildup can cause the tips to work loose and/or break the seal. Also, tips that aren’t clean (due to a coating of ear wax, oils, or dirt) can cause the tips to work loose and/or break the seal.
6. Then there’s the shell itself. You can’t change your ear anatomy, but sometimes you can change the shell. Some shells have a pretty big protrusion for the concha (specifically, the concha cymba). This can cause for problems for some people. Some people have sanded off some of the protrusion to resolve fit or comfort issues. I've seen it done to the ZS3, ZSR, ZSX, etc.
7. You can always do some additional mods to the shells to improve the fit. Sometimes all it takes is $0.03 worth of thermoplastic. The 1st one was done by another member, and the others were done by me.