I have pioneer 5 channel AVR. I need a 9 channel AVR now . I was thinking to get denon 4500h. Or should I get a 7 channel avr like 3500h or 2500h and use the old avr for +2 channels. Is it difficult to manage 2 avr , powering them etc. Considering the price difference, would it make sense to get atmos 7 channel avr and extend to 9 channel. Please suggest.