Photos: Headphone upgrade? Hear you go

Here are some of the headphone options available to improve the listening experience of portable music players.

Etymotic Research's 6i Isolator Earphones offer a sound-isolating option for $150. These include enhanced bass and can reduce outside sounds by an estimated 35 decibels, according to the company. Two types of tips are provided, including a foamlike material you squeeze before putting them in your ears, and they slowly expand to form a seal.