As i said, we could ignore all the detail to a certain extent and let it be. This IS a combat roleplay after all, not a hard sci-fi writing club.

But if we should go with it, then i should mention that sound waves don't produce disortions in the air visible to the human eye, even at high freqencies and high energy yeild. Sol's sheath also wouldn't have the ability to bloack out the wave completely, as neither it is as large as Ido's palm, from which he launches the attack, nor does it have any properties that prevent the wave from travelling through it. It will absorb some energy, but not all. And finaly, a sound wave probably wouldn't knock down a person with its force - instead, the sound wave simply passes through the body, causing the tissue to rapidly vibrate, putting it under great stress and eventualy rupturing or cracking it.

Also, fastest reaction speed (in other words, the time that passes between seeing something and reacting to it) for huamns is approx. 100-150 milliseconds, while the average is 200-250. Comparing that to the time it takes sound to cover 7 meters, which is less than 25 milliseconds, it has to be aknowleged that Sol cannot do anything after it is launched.