Sony MDR-NC6 Headphones

Pros: High fidelity, effective noise reduction (within limits).

Cons: Some hiss audible at low ambient noise levels.

Summary: Some of the other reveiwers seem confused about these headphones. These are noise cancelling headphones - of a certain capability. And although there is some hiss audible in the active mode, they are not just pink-noise generators. These headphones do not cancel random noises or sounds like bangs, talking or babies crying. What they do cancell is repetive noise like roars, rumbles and droning sounds: just the sounds you get on an airplane or in some industrial environments. When I first got these, even though it was not hot outside, I turned on my air conditioner just so I could stand beside it and turn the noice cancellation feature on and off. The difference was dramatic, and I expect it will be so on an airplane (the reason I bought these). In my office, there is an HVAC rumble. I don't notice it much, but if I put on these headphones, I can eleminate it; but I will hear a hiss that is inadvertent noise from the headphone system. Also, because the noise is sensed with microphones on the outside of the earcups, running or cycling with these headphones is not onlyl dangerous, but not very satisfactory because the microphones pick up air-turbulence and they try to cancel that noise and that produces an odd sound (because the wind noise is not repetitive enough for the cirucit to deal with).

One more point: when you put the headphones into active mode with a source, the source gets about 3dB louder (like one "step" on a volume control) vs. the inactive (off) mode. I find this helpful, as I use these to watch movies on my laptop on planes, and my laptop headphone output is not very loud even all the way up. These headphones give it that needed extra boost.

So, in summary, for reptitive noise like you get on an airplane, these units do work and cannot be beat for the price. If it were not for the hiss, these things would score a 10.