I love in-ear headphones--the ones that fit inside your ear canals, as opposed to ear buds that rest on the outer ear. I'm a big fan because in-ear headphones' ultraclose proximity to eardrums offers the potential for the highest-resolution sound quality.
The better in-ear headphones also do a great job of sealing out external environmental noise so you can listen at a lower (safer) volume and still hear all of that amazing detail. The problem is, unless both earpieces are sealed tight, you're not going to get the sound you paid for.
Everybody's ears are different, so achieving a perfect fit can be a tricky exercise. Most in-ear headphones come with a selection of differently sized and shaped eartips. Try them all; the goal is to produce a the best possible "seal," which reduces the amount of outside noise you hear and delivers the headphone's fullest-possible bass response.
The difference in sound quality between a good seal and an iffy one isn't subtle. It's definitely worth a little extra effort to maximize each tip's seal. Remember, too, that poor sealing makes for a less secure fit, so the earpiece is more likely to fall out of your ear.
Tip: Your left and right ear canals may not be exactly the same size; you might need, for example, the smallest eartip for your right ear and a medium tip for the left ear.
I've included a gallery of images to help perfect your in-ear insertion techniques. First, try rotating/twisting the tip slightly as you push the headphone inside the canal. … Read more