Prevent play before all things get loaded

I have a page where I am showing multiple instances of soundmanager2 (with different files).
There is no problem with player if I wait for page to load completely and then try to play a sound.
But, if I try to play a file before whole page is loaded I am getting mp3 file directly played in browser.

I've tried to put waitForWindowLoad = true; in soundmanager2_config.js but it does not make any difference.

Should I use some other property to prevent this? Or there is some other way?

Thanks in advance

Mihajlo
Kontrola