a reflector employs materials and design features that can transfer both light and sound emission simultaneously , from sources to planes or volumes , in an efficient and controlled manner . compound orthogonal parabolic reflectors employ an extension onto conventional orthogonal parabolic reflectors to efficiently deliver light and / or sound to a focal volume or surface . the extension shapes the output , and can provide inflow and outflow to the focal region , along with a brush . pulsed sources may be employed , which may emit light , sound or both light and sound , may erode and may be wire initiated with the wire replaced after each pulse by a wire feed .