Brian Gaff wrote:

----------------------

Oh I know about those as they are used for audio description in cinemas and
theatres. I was thinking more of exhibitions where an exhibit has a button
to press to hear a description, but if there are a lot of these the sound
when used normally is spilling over to other exhibits and hence makes it
hard to detect the one you want.



** IR headphones can do that job, just define the IR energy to a marked area near the exhibit and illuminate from above.


...... Phil