Recently picked up a Sony dz710 for next to nothing. Speakers work but I think the ones from my Onkyo HT r390 sounded better. I'm wondering if it's safe to hook them up to this receiver, including the passive sub. have not been able to find specifications for the speakers themselves but the Onkyo receiver was rated at 6 ohms impedance in the Sony is rated at 4 ohms. There's more watts per channel coming from the Sony as well. Just curious if it would be safe for the receiver and the speakers to use the Onkyos. I'm not sure what I would check to verify this. Thanks in advance.