I think they are more sophisticated than white-noise makers. I think they create an out-of-phase equivalent to ambient noise in the lower frequencies, and the combination of the ambient noise and the out-of-phase noise is heard as no noise. However, none of them is perfect, and I'm not sure I would want something that blocked all ambient noise, such as fire alarms or sirens.

I hope everyone wears something on their ears, if you are on a plane,train, etc. with me !! I have stayed awake when everyone is asleep , slept in bathtubs, on the floor, you name it. Just so I don't keep everyone awake when I snore.

It is so awful (DH taped me !) and I'm so embarassed. Have tried everything but surgery. Know about apnea, etc.

Just part of me-so wear something-my fellow snorer might be near you. !!

Have fun wherever you go.

I have a pair of Sennheiser NC headphones that are just great. They fold up into a small pouch, so they're easy to travel with. I like them better than the bigger Bose style since they don't get in the way if I wish to lean my head on a pillow.

They do an excellent job of cancelling out the 'White Noise" on an airplane - fans, engine noise, etc.

The biggest problem with cancelling out the "White Noise" on a crowded plane, however, is that is doesn't cancel out the "White Trash Noise".

Beforehand the engine roar would drown out others' conversations, now with the NC headphones every word of the most annoying, inane, endless conversation about nothing around me is guaranteed to make a bee line to my brain.

That's when I just turn up my MP3 player one notch and escape to my own quiet world.

So, J62, they cancel out the white noise and you hear all the inside the plane noises loud and clear (babies' crying, normal conversations, etc.) is that what you're saying?

I thought they were effective at blocking all noise except whatever sound-source you had them plugged into! Please explain.

I have a pair of the Plane Quiet headphones and have been very happy with them. I can even sleep with them on. I just couldn't see shelling out all that $$$ for the Bose. :)

DeeDee,
Yes, if you use noice canceling headphone alone, without plugging into anything like an iPod, they can have the effect of actually letting through normal sounds.

That's one reason many people like the larger earmuff types that cup the entire ear. The noise cancellation blocks out the low frequency sounds (engine, fans, etc) and the insulate cup over your ear blocks conversations (crying...)

One reason I like the small ones I have is that I can carry on a conversation with the person next to me while wearing them. I know it looks odd or rude but I'm always much more relaxed after a flight if I've had them on (even in the terminal)