Hi. 
I will give four sound the countdown. 
1.mp3, 2.mp3, 3.mp3, go.mp3 
I write this: 
 g_RaceStartCountdown = Countdown.create(6, launchRace) 
g_RaceStartCountdown:useImages('img/countdown_%d.png', 474, 204) 
g_RaceStartCountdown:enableFade(true) 
g_RaceStartCountdown:addClientHook(3, 'playSoundFrontEnd("audio/3.mp3")', 44) 
g_RaceStartCountdown:addClientHook(2, 'playSoundFrontEnd("audio/2.mp3")', 44) 
g_RaceStartCountdown:addClientHook(1, 'playSoundFrontEnd("audio/1.mp3")', 44) 
g_RaceStartCountdown:addClientHook(0, 'playSoundFrontEnd("audio/0.mp3")', 45) 
But this wrongly. 
Help me pls.