[AIped]

good question, there must be several ways to do that but one thing you do need is
IsPlayerInRangeOfPoint then let the audio stream like this;

pawn Код:

if(IsPlayerInRangeOfPoint(playerid, 5.0 ,1529.6,-1691.2,13.3  ))//5.0 or any range you prefer
{
    PlayAudioStreamForPlayer(playerid,"MUSIC HERE");
}

a bigger problem is how are you going to call IsPlayerInRangeOfPoint..a timer is realy buggy i guess