Do people have favourite brands? What does wide and narrow tunnel do?
You mean the bore? That primarily determines whether they'll even fit over your IEMs.
Too wide and they won't get any traction; not tight and depending on how much traction there is on the outer side vs your skin, they'll seem like they fit but will slip off when you take the IEMs out of your ears. A little tight and you need a tweezer used in reverse ie like forceps to stretch out the bore before you fit them over the IEM's bore, be sloppy and you can damage the IEM; too tight, even if you stretch it to fit, and the end of it might contract and close, which usually affects the top end of the range while lowering sensitivity.
Depends...do you want it sticking in deeper for isolation or for them to stick well, depending on how the taper towards the end is like?
If it's too long and quite tight over the IEM bore you have a lot more tip bore to work with when fitting it over your IEM's bore (your tweeceps need to come in from the other side,stretch them over the IEM bore, then you slowly pull off the tweeceps).
Depends...do you prefer a plasticky feel that may or may not be pliable enough? Or do you prefer very pliable but cheap ones itch and the good ones are smoothened out and kind of waxed, but either way can start falling apart sooner than silicone takes on the texture of beef jerky?
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Bottomline, it's really up to each user what they want in terms of ergonomics and then it depends on each IEM as to whether the sound is noticeably different, then back to the user as to whether the changes are preferable.
