#define id skill100
#define a_sound_emitter 1

action Sound_Emitter()
{
   my.id = a_sound_emitter;
   var explowham = 0;
   while(my){
      if (key_space && !snd_playing(explowham)){
         explowham = ent_playsound(me, snd_explo_wham, 200);  
         scan_mode = (SCAN_ENTS | SCAN_LIMIT | IGNORE_ME);
         c_scan(my.x,my.pan,vector(360,0,200), scan_mode);
      }
   wait(1);
   }
}

void _event_react_on_snd(){
   if (you) if (you.id == a_sound_emitter){
    //place the reaction code here, entity heard the sound
   }
}

action Entity_React_On_Sound(){
   my.emask |= ENABLE_SCAN;
   my.event = _event_react_on_snd;
   ...
   ..
}