Its best not to put any speakers in the rear except for subs since they are non directional unless you like pulling from your soundstage ....Do you like listening to a concert in front of you or while your up leaving and walking out the door ?
I have one of those decks on the shelf also ...i have several of those cheap Android decks ...some have some really nice sound processing some are basic ....i waa messing around with a few of my decks earlier this evening ...i may drag my Joying out