Flash audio off sync *sounds* help!

Alright on my last flash i was making i trashed it for the sole reason of the sounds going way off sync, they were all streamed… but i made like 9 scenes, bc i didnt know using to many scenes is bad, so i used the scenes alot, but in my new movie im gonna use as little scenes as possible to try and keep the sound on cue, well… how many frames can i have in a scene before i gotta make a new scene preventing the sounds going out of snyc… or any help to keep things in sync, and like i said before they all are already in “stream” mode, and i animate at 18fps, plz plz plz help me, Thx so much in advance!