I would try to start with one EP500 and if after experimenting you just feel you must have another subwoofer then add another EP500 later. That’s assuming you get buying another one by the WAF later as she may feel one is more than enough.

3M80 2M22 6QS8 2M2 1EP500 Sony BDP-S590 Panny-7000 Onkyo-3007 Carada-134 Xbox Buttkicker AS-EQ1