Measure your alts voltage at the front battery, or alt its self. See if its higher than in the rear. You may have a wiring issue.Let's assume that the amplifier RMS watt rating is honest at 14.4V. What do we do if the alternator puts out something like 13.8V or so? Is there a formula to deduce the RMS watt limit at lower voltage?
Not true. My amp is 1/2 power at 12V. Your formula implies that it should be 12/14.44 or 83%. Some amps can maintain full power at lower voltages, some can't.Yes well this is my best shot at it, if everything else stays the same efficiency and such, since the amplifier is linear with respect to voltage then it should be just a ratio between (oem rms watts)/14.4=(rms watts at lower voltage)/13.8 and just solve for the rms watts at lower voltage. By multiplying 13.8 to each side.