load calculation

you can get those speakers down to a 4 ohm load so that you will get 500 watts to the subs. You change the ohm load by the wiring of the subs, either series or parallel. Check out the General Info section of this site and mess with the parallel and series calculator. If  you want to get a better understanding of all of this i would recommend you take some time and look over this site www.bcae1.com        later

An amplifier will operate into whatever load you place on it.  The load is measured in ohms.  The number of ohms is determined by the wiring of the speakers, the amp does not determine this.  Amplifiers include ratings listing potential output into various ohm loads, and listing the MINIMUM safe load that must be placed on the amp.  If a lower load (number of ohms) is on the amp, it will shut down or blow a fuse or fry (AKA smoke.)  But there is really no practical maximum.  The total power output of an amplifier will simply vary depending on the total load, due to Ohm's Law (and other phenomenon.)  You can load an amp with as many speakers as you like as long as the wiring is such that the minimum total impedence load is not exceeded.  Some arrangements, of course, sound better than others.

If you have a specific application in mind, list your speakers (make and model) and your amp (make and model) and we can help you determine the best way to wire it so you get the most out of your amp without overloading it and without blowing your speakers.