Sprinters in the position farthest from the pistols were getting slower start times, so organizers switched to an electronic tone.

The speakers behind each athlete that will "play" the pistols starting tone (OMEGA)

When the Olympic runners take to their positions on the track later this week, they'll crouch on the ground, ears pricked, and wait for the starting beep. That's right, a beep. Not the pow of a gun, but an electronic tone, pumped through speakers, played by a "pistol" that's not a pistol at all, but something more akin to an electronic instrument with only one key. The pistol itself is silent.

The Olympic "gun"

The electronic "pistol" of this summer's Games was designed to overcome an astonishing problem: The speed of sound is too slow for Olympic athletes. That is to say, athletes far away from the starting pistol were delayed by the time it took for the sound to travel to them, and differences so tiny can matter in races in which the margins are so small.

For decades, to fix this problem, sports-event organizers have placed speakers behind athletes (swimmers, runners, speed skaters, etc.) to convey the sound of an actual pistol. But they found that even though the noise came through the speakers all at once, athletes continued to wait for the "real" sound, ignoring the sounds that came through the speakers ever-so-slightly earlier. As Peter Hürzeler of OMEGA Timing told me, a conversation with sprinter Michael Johnson at the Sydney Olympics caused him to realize that even with speakers, the speed of sound was still slowing down the farthest athletes. Johnson's reaction time, Hurzeler said, "was 440 thousandths of a second. Normally athletes leave between 130 and 140 thousandths of a second. ... I asked him, why did you have such a bad starting time?" Turned out, Johnson was in the ninth position, and the sound of the gun was reaching him too slowly. Beginning at the Vancouver Olympics in 2010, OMEGA switched to the current "silent" pistol technology, erasing the thousandths of of a second that stood between runner nine and runner one.