There are many choices in noise cancelling headphones and ear buds. The Sony are inferior to some of the cheaper ones, with the Aldi Bauhn being really good at giving a real 'hush', and the Bose ear buds are just brilliant.
axtyr, if you have never used NC phones or buds then you will not know how good they are. They do not cancel out faint signals, but in fact enhance them as they only cancel out 'white' noise. Many have a slight amplification when switched on while some do not. Most have their own built in rechargeable battery while others require the battery to be replaced or recharged externally.
Most varieties do not remove outside noises such as cars or voices, although the Bose ear buds shut out almost everything, which could present the odd problem, although I use them a lot, as in summer I like to wear a broad brimmed hat. Some head phones can also be hot and sweaty, especially the Koss.
I have been using NC phones for years, the first brand being Jabra. These are quite good, although they require the batteries (one per side) to be charged externally. I believe that they are now superseded and replaced by the brand 'Black Box' which from what I can see are identical. If you can pick up either of these they are an effective product. There is no latency or lag on the ones I have used, but the Bluetooth versions may have. I use mine in conjunction with the Quest cordless system, a combination that works just great.
