No, the amplification can only work at the speed of sound, neither faster nor slower. The paper analyzes how the wffect falls apart when you deviate from c. Wh

No, the amplification can only work at the speed of sound, neither faster nor slower. The paper analyzes how the wffect falls apart when you deviate from c. What you possibly could do is to have multiple laser beams forming a sweeping comb pattern. Depending on dispersiom and other effects, you might be able to do some waveform shaping. But that is very elaborate for a loudspeaker.