A method for establishing communication between a computer program in a computing system and a pair of controllers held in hands of a user, comprising the computing system to perform the steps of: capturing using an image capture device , image data in a capture area in front of a display , wherein the image capture device is located proximate to the display; synchronizing clocks between the two ends of one-way sound communication, wherein one end is located proximate to the display device and opposite ends are located at the controllers; performing, using corresponding sound capture and sound emitting devices , one-way sound communication between respective ends of said one-way sound communication; capturing , using the sound capture device , said one-way sound communication; performing, using sound interfaces at each controller, two-way sound communication between the pair of controllers, the communication comprising information indicative of the separation of the two controllers; receiving the information from one or both of the controllers; and computing , using the image data and the received information indicative of the separation of the two controllers, a two-dimensional location of each controller in the capture area, wherein the separation comprises a distance between the pair of controllers computed in accordance with the two-way sound communication, and computing, using the captured sound communication and clock synchronisation information, a third-dimensional location of each controller, wherein the third-dimensional location comprises for each controller a distance or depth in the capture area computed in accordance with said one-way sound communication. capturing using an image capture device , image data in a capture area in front of a display , wherein the image capture device is located proximate to the display; synchronizing clocks between the two ends of one-way sound communication, wherein one end is located proximate to the display device and opposite ends are located at the controllers; performing, using corresponding sound capture and sound emitting devices , one-way sound communication between respective ends of said one-way sound communication; capturing , using the sound capture device , said one-way sound communication; performing, using sound interfaces at each controller, two-way sound communication between the pair of controllers, the communication comprising information indicative of the separation of the two controllers; receiving the information from one or both of the controllers; and computing , using the image data and the received information indicative of the separation of the two controllers, a two-dimensional location of each controller in the capture area, wherein the separation comprises a distance between the pair of controllers computed in accordance with the two-way sound communication, and computing, using the captured sound communication and clock synchronisation information, a third-dimensional location of each controller, wherein the third-dimensional location comprises for each controller a distance or depth in the capture area computed in accordance with said one-way sound communication. <EOS>