Syncing several animations and audio?

Dumb question, but still did not find any clear answer by using google of search on this forum.

I made one animation which is 60fps and 3000 frames long.
There are also several other animations in different game objects, which are exactly the same framerate (60fps) and lenght (3000 frames).
I have also audiosource that is playing audio which length matches to 3000 frames @ 60fps = 50seconds.
These all are in loop -mode.

So, it could be described that I am using Unity as a "film editing software", but for a purpose..

But, now when I play my "video", all the animations and audio start with sync, but start to go off sync after looping for several hours. So now I am asking if there would be some kind of Sync, Deltatime, or somekind of simple way to get all of these start and work in Sync? Starting animations in the first frame or something like that?

Thanks!

 

you can try timeline.