Ok im comfused on this some amps say theyll produce 120 watts ( rms power) into 12.5 volts but then it says 175 watts rms in 14.5 volts Whats the deal with that? can u choose to have it playing at 12.5 or 14.5 volts
battery sits at 12.6 when car is off around 13.8 at idle and around 14 at higher rpms.
when testing amps for output, they are not tested inside a car, they are on a bench with a variable DC power supply that can be adjusted and held for a constant 14.4V, which is the most a car will usually ever be at, and therefore the companies will post thoes numbers for the public.
every time you turn something on in the car, especially a high power stereo system, that will pull power and you will see a drop in voltage. the more the voltage drops, the less the output at the amps.
to keep from getting these drops, you will need a more powerful electrical system. HO Alternator, higher quality batteries, larger wires...ect.