How do I measure how loud a car audio system is?

Car Audio System makes my car overheat? why?

• there is nothing online about car audio system is related to overheating of car.. but my car has this issue. when i on the radio, the car starts to overheat, when i off the radio, the car temperature goes back to normal. why is this happening? I installed a new audio system with 2 midway and 2 3-way speakers plus a preamp and an amplifier. when i on the radio, or some songs, the car starts to overheat. due to this matter, i went to the mechanic and ask them why.. they said it has nothing to do with my car cooling system. so, they said to me they help fix the cooling system just to make me satisfied to prevent any overheating of my car. they changed for me the U-tube, cleaned the radiator, changed the thermostat, add coolent to it. after that, my car still has the same issue. so i took it for a 400KM ride. it turns out that long journey, it overheats too. before going, i checked my car, added coolent to it too. my car has max of 6 bars of heat indicator levels. the normal temperature level is 3 bars, but it keep going up to 4 bars every time i on the audio system. especially when i on it loud. but then when i accelerate a lot, the temperature will drop back to 3 bars. if i dont accelerate, it will stay at 4 bars for 80% of the time. once i rest at a stop, i went for a slight rest, when i came back and on my car, suddenly the temperature is at Warning level which is up till 5 bars. i on my engine and my car cooled down slowly. i seriously asked around and nobody knows what is happening to my car..

• Answer:

  My guess is that you need a new battery so that your alt can get the power it needs to put out to your new system. if not a battery then it may be the alternator and that it cant keep up with the demands of your system. at car audio competitions they idle at 2000rpm because thats when your alternator is at its best. try to take your car to a car audio shop and see what they say.