If you do not mind experimenting, you might see if you can get a
surplus headset that has the cancelling technology, along with as
much technical info as possible. One or two microphones placed
That is the original idea. But I have heard that it works even better
to put the reference mic inside the headphone, and apply negative
feedback to make the sound inside follow the sound you want, whether it
is music or silence.
That way it doesn't matter what the outside noise is, everything which
is not exactly the wanted sound is cancelled.
Simply apply negative feedback from the mic to make sure that the sound
inside is exactly silence, that will automatically cancel any
disturbancies, whether electronic or acoustic in origin. It is similar
to the motion feedback system Philips used in loudspeakers once. It
forces the sound in front of the loudspeaker to be an exact copy of the
sound signal you want, or silence if that is the result you want.
Talking about the problem in general terms and in rooms also:
You need a passiv screen between the ear and the noise, which dampens
the treble sounds and makes it a lot easier to apply electronic noise
cancelling. In a room this screen can be the walls, in a headphone this
screen is the outer plastic material. Heavy cloth materials dampen
The problem is more difficult in a room or apartment, if you want to
cancel noise no matter where you are in the room.
It is easier to cancel noise electronically for a listener in a certain
position in the room.
In a room it can be enough to play some own music, to avoid total
silence, which make the ears more sensible for occasional noise from