Opposite the new "Treasures Gallery" of the National Library of Australia there are five Expo Mark II sound chairs, in a semicircle in front of a wall screen. These high-backed chairs were designed for the Australian pavilion at Expo 67. They have a hard cylindrical shell and sound adsorbing fabric, with a loudspeaker in the the wing next to each ear, providing a remarkable surround sound effect.
Unfortunately the chairs are not adjustable: I found the base too high for my legs and the back too low. As a result the chairs are extremely uncomfortable, unless you happen to have very long legs and a short torso. The design need to be brought up to date for the 21st Century by being made adjustable.
The uncomfortable seating may be deliberate, as the NLA has a 2 minute video loop running. If you sit for more than a few minutes you will be driven to distraction, hearing the same thing over and over again.
These chars are also on permanent exhibition at the National Museum of Australia.