I have recently been working on a custom sound system in my living room. For the subwoofer, I am using a 1000W amplifier. This is currently running off of a 12V computer power supply that outputs around 650W (The power supply shuts off at a certain volume because of lack of power). I have another power supply (not a computer power supply) that is 500W but has a voltage of 13.5V, not 12. I've read that this voltage is actually better for running car audio equipment and I am using another 13.5V power supply for the head unit to power the highs and mids.
I am wondering if it would be possible for me to connect these two power supplies in parallel to increase the power to this amplifier since they are both safe voltages. Would this be possible? Would I need to use a resistor to match voltages? Or is this just not a good idea altogether?
Update: This is car audio equipment so high power ratings should not be a shock.