A voice modulator that you can choose to change your singing voice changed to match the singer of the song simply by having the computerized Karaoke machine (which memorized all the singer's vocal details) change the pitch, octave, vibrato, etc. Basically a synthesizer that creates the closest match to the actual singer's sound within a certain chosen song. You could even be a man and sing and sound like Madonna! Ha! Not hard to change your sound digitally, but the memory the computer...