The countdown sample on FGF is crappy ...
Anyone who practices standing starts wants to 'sync their clock', which is to say, to get your timing spot-on.
At championship events, you get a beep at 10s to go, then 5,4,3,2 & 1 are beeps, then a different tone beep for 0.
There's a recorded sample of this over on Fixedgearfever, but it's full of background noise and is generally a bit ordinary. So I sat down for 15 mins or so with Audacity and made a new one. Here it is. Feel free to use/abuse/distribute as you see fit.