"Sound quality is fair but bass is lacking"2.5 starson by bswanwa
Pros: The size is right, good for noise cancelling
Cons: Very little bass response, hard to get earplugs to fit right
Summary: I bought the ER-6i headphones to compliment my I-Pod. I like the small size, and it's noise cancelling abilities are very good, however, the overall sound quality itself is somewhat lackluster. There's virtually no bass response, and even the high and mid-tone sounds fall a little flat. It's not bad, and the sound is actually pretty clear, but I expected better sound quality for the price they want. I'll admit, I've been spoiled by my old Sony MDR-7506 Professional Studio Monitor headphones, but that is a full-size headseat, and somewhat cumbersome to tote around. Nevertheless, the sound quality and bass response of those Sony studio monitors is practically unmatched. As far as the Etymotic ER-6i goes, the sound qaulity could be better, and I am finding it hard to get that "perfect" fit in my ears to supposedly get the best sound, even when the ear buds are buried deep in my ear canal, like the instructions tell you to do. If you have to work that hard to get the best sound, then these headphones really aren't worth it. To the average person who isn't as much of an audiofile as I am, these headphones will work fine, but shop around. There are cheaper headphones which will work just as well.Updated
I've now had the ER-6i headphones for 3 months or so. I gradually warmed up to them and got so I didn't mind the low bass response since the clarity was so good. Guess what? - the headphones broke the other day! I didn't think I'd been particularly hard on them (I was always careful taking them in and out of my ears and I was stowing them properly), but all of a sudden, there's no sound coming out of the left speaker. The cords ARE pretty thin on these headphones and may require extra sensitive care and handing, so those of you who own these headphones, just be cautious of how you use them. They don't seem to be as durable as other types.
I've now abandoned Etymotic having just bought the Shure E4c headphones. Yes - they are more expensive but the bass response out of the Shure headphones is MUCH better than the Etymotic. They are also more durable - cord is thicker, etc. I'll post a review on the Shure model after I've used them for awile.