If it's going to be no longer than about 15'... Most of the charts will tell you to go bigger, but in actuality -- current draw of a ~1500w class D amp will be well within the limits of 4 ga. Competitors would tell you otherwise, being against their "rules" and all -- but fuse it no more than 125A and it should work fine. If you have another amp (front speakers?) you'll either need bigger wire or you'll have to run a 2nd wire.
since u have a fairly powerful bass amp i would think u also own a good mids amp & both would be running on the same power wire so my advice is to buy 0g that way in case u ever upgrade u will be covered still with good wire .....