4 gauge but remember that you may want to upgrade in the future so i would recommend 0 gauge from the start, and using a distribution block to step down the wire size at the amp until and/or if you upgrade
its more cost effective that way because you don’t have to pull out the old wire and start from scratch
hope i heped, good luck
It really depends on how much power your amp requires. Most systems will be perfectly fine with 4 gauge. I have 2 amps running off 4 gauge. One puts out about 400 watts RMS and the other puts off 120 watts RMS. Max watts is like 1600 or so. good luck
It depends on the LENGTH and the RMS going through.
For example, i have 4 foot wires running 325RMS using 8gauge and its lots.
You would have to give us a length and RMS power to determine.
It just depends on how many amps are used or the total rms wattage.Whatever wattage you use will corespond to wire size.Most amp kits state the amount of wattage they are rated for.