Transcription:
By Jesse Squire @tracksuperfan · 1h
If I did my math right, those starting block speakers made a difference last night.
Without them, Lyles would have been at a disadvantage of 0.008 sec — how long the sound of the pistol takes to travel from lane 4 (Thompson) to lane 7 (Lylesh).
He won by 0.005.
[A picture showing starting blocks on the track with runners' feet in them. Behind each starter block is a purple loudspeaker connected to wires leading out of frame.]
They are more saying that using loudspeakers is better than a traditional starter pistol shooting a blank.
Since a starter pistol would be fired from either the inside, or outside of the track, the sound of it would take about .026 seconds (more than the .005 seconds) to reach the other side. This is estimating the air is around 20C.
With loudspeakers, as another user mentioned, you can theoretically ignore the length of wire as it would travel close to the speed of light. (~0.000000045 seconds using 99.9% Cu, if you are curious) Since the loudspeakers each are also an identical distance from their starting blocks, each of the athletes would hear the crack at the very same time.