This device, by its organization and operation, processes sound, usually music. It provides output voltages, for driving lights, which is proportionally representative of input sound levels. Range of sound perception of the human ear exceeds the range of perception of the human eye. It is necessary to adjust the sound level by compression and Automatic Gain Control, particularly by compression, to accommodate the eyes.
A requirement to have the output drive voltage drive the lights is to have a linear response to the compressed audio signal. This requirement is met with an output drive circuit which, has a linear response to the compressed signal. This is achieved with a linear firing circuit when providing output voltage using SCR's or Triacs. In a straightforward variation of the output circuit to improve the power factor, the linear response is maintained by modulating the output with transistors instead of using SCR's or Triacs.