I have a pair of the Sennheiser noiseguard headphones and have just got back from hols.
On the plane I watched the movie with noiseguard on and the volume was quite low. I then switched it off and had to turn the volume up by quite a bit and still had trouble getting all the dialogue.
INHO they are GREAT
I got them gor £80 from ASK on Tottenham Court Road (London), priced at £90 everywhere else
They are not dangerous to use when out as they only cut constant noise such as plane engines etc. as they use electronics to produce an exact reverse of a sound wave that then cancels both out, therefore talking etc can be heard (as long as music is not too loud).
Pioneer (I think) also do small in-ear headphones and can be found in the Index catalogue at around £50, but I have not tried these.
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