Grim noise reduction, however, with the usual prudent background hum available in all noise canceling headphones. No one notices if you have music on, even extremely low volumes but if one decides to put on his headphones in a quiet room and turn on the noise reduction it is reflected. Bit pointless but still good to know about buying and testing them at home. Having said that reduces the background noise from the traffic in my apartment in Stockholm in a fantastic way, started to walk around with them at home, even without music ...
The sound then, new out of the box they sounded really not fun, the base was uncontrolled and strange, they were at times sharp and seemed to have a really bad day in general. These headphones need to lie and play for a little while, need not take long at all, quickly becomes better, I pulled on the volume and played a disc after it worth it amazing much better. So, when you unpack them, drive them started and let it sit for an hour or so. You'll be a lot happier ... Maybe my copy but I have experienced the same thing with both my Sennheiser (HD 25 and 650) which took much longer time to be recorded.
Once recorded, they have a nice, pleasant sound character that feels focused on not tire the listener and create music as a whole, not standalone details. They are not nearly as rap and "exact" such as HD25 headphones but tillochmed I like the hi-fi enthusiast notice that I go around with Bose headphones very often. The audio profile and noise suppression makes them a great fit for listening to a little lower volume. There is absolutely nothing wrong with the sound of dragging on but where I find myself constantly like to raise with my Sennheiser I notice that I can do with much lower volume of Bose headphones and still dig the music. There is so much difference I guess that Bose headphones will lead to that I may preserve my hearing a significant number of extra years than if I would not wear them everyday / commuter lit up.
Conclusion: Yes, there are tricks that sounds more hifi, more detailed, more accurate, with a larger soundstage and all high-fidelity parameters one can enumerate. Sennheiser HD25 is a good example, they are cheaper and sounds better. But, I who have both and have a ridiculously expensive stereo, use the Bose headphones a lot more than my Sennheiser. They make life more relaxed, making it more quietly listening to music, traveling by train, sitting in a cafe and work or even be home in an apartment in town and is so comfortable to both carry and listen to that I have them to me in season and out. So, expensive, yes, but if you count cent per hourly use, they are a bargain. And since they clearly do not have any ambition to be number one in terms of accurate high fidelity reproduction, it becomes top grades, they are simply crazy good at what they purport to be.