Noise canceling headphones?

I have a pair of the Sennheisers and have mixed feelings about them. Even with no noise around you, switching them on severely alters the timber of the music. They do cancel out some noise and boost the high frequencies, but they are not that comfortable and turning on the canceling feature often makes my ears pop (like changing elevation). I've use them on several trips and wished they canceled even more noise than they do ( only about 10db, and none at higher frequencies). Bottom line, they do help, but if I had to do it over, I would go to the Etymotic.

I have tried a cheap Brookstone and the Sennheiser NC headphones and agree with what's posted above. I do find it relaxing on long flights but the sound quality is not very good compared to the better Sennheiser's and Grado's. I have not tried the Etymotic.

I fly regularly between NY and London and I have both the etymotics and a pair of Sony noise canceling headphones. I find the Etymotics a bit thin sounding and quite uncomfortable after an hour or so, although the custom ear pieces might help. Has anyone tried custom ear things for the etymotics? The Sony phones were also pricey ($300?) and they don't sound great but I find the noise canceling circuitry very effective and a great relief. I should point out that they are soft, rubber, in the ear type headphones and not over the ear which perhaps makes a difference. I feel less fatigue from the flights and enjoy the in flight entertainment, DVDs, MP-3 files etc. In any case the guys at Headroom are great and I love their amps. Good luck.