Starter distance and lag

In minor competition the starter shot the gun,the sound travels until the sprinters.Since(at 15°C) usually the speed of sound is about 340 m/s,and the starter is usually 15-20m from the sprinters,it take 0.06" before them can begon to react.

In major competition,behind the block we have a small megaphone connected with the gun.does this connection provide an immediate responde?If yes, we can say that in minor races the athletes are slower depedning from the starte position? (0.03" for 10m distance).

Which way is the wind blowing and what is the wind velocity??? Is this at sea level???

TNT

yes 340 meters/second is on the sea level at 15 Celsius(or 25 i don’t rememeber).
Wind can affect,but here i am talking only about the speed of sound.

it was a problem in sydney