I have owned teh ER4Ps for 2.5 years now and use them mainly for airplane flights. They allow me to hear music from my MP3 player or the plane's movie without having to crank up volume and thus protecting my ears from noise polution (for listining to airplane movies a volume control would be good, as the plane's minimal sound level is quite strong for these headphones). They also work great when trying to sleep in a plane; unplug, and it turns quiet. Sound quality is excellent! The only downside is the cord, which is more rigid/noisy (when it rubs against itself) then I'd like. I also owned a sennheizer headphone for the same objective, but the ER4P is a lot more convenient and sounds better.