Apparatus (11) for providing an output of: (i) electromagnetic waves; (ii) sound waves; or (iii) both electromagnetic and sound waves comprises a power supply, support structure (13), control means and a plurality of transmitters (15) arranged in a linear array on said support structure (13) and in electrical contact with said control means, wherein each transmitter (15) is controllable individually and independently from other transmitters. To provide a coloured lighting effect, apparatus can comprise a first source of light of a first colour, a second source of light of a second colour, different from the first colour and a diffuser (12) for diffusing the light from the first and second sources so that the diffused light from the diffuser is perceived to have different colour, shade or hue. Uses of the apparatus are described, for applications such as entertainment, safety, directional and speed control, such as in providing a linear sound and/or lighting effect in which the output is perceived as emanating from a substantially continuous sound and/or light source rather than from a plurality of individual sources.