This program generates signals to test loudspeakers with the help of a synchronised LED stroboscope. The only external hardware needed is a two channel amplifier and an LED flashlight. Traditionally these tests are done with dedicated, inflexible hardware devices costing several thousand dollars or Euros. In this program the computer sound card supplies the two signals to the two channel amplifier. The speaker signal (sine wave on the left channel) is amplified and sent to the loudspeaker under test. The other signal is the light trigger pulse on the right channel. It is sent to the external trigger input of a stroboscope or it can also be amplified and sent directly to LEDs. A standard LED flashlight (British English: torch) is ideal as a stroboscope.