Personally, I wouldn't put the front right and left speakers behind the screen for multiple reasons. For one, you can move them around to get the best imaging for two channel (for those of us, like me, who value two channel way more than 5+ channel). Because the speakers are into the room, you ban better balance low frequency response (where more drivers = good). Plus, you can get some bigger, taller speakers (depending on the size of the screen, room situation, etc.). And you're not limited to sealed/front ported speakers.