How do you know how many watts you're feeding into your speakers and subwoofers at a given time? For instance, I have two JL 10w6v2s in my car and it's recommended that they not exceed anything over 400 watts, but how do you know if you're exceeding that amount? Same goes for speakers. They have power handling levels, well for mine, from 20-150 watts, but how do you know exactly how many watts you're feeding into them at a given time? If you turn up the volume, I assume it draws more power (watts), but how do you know if you're exceeding the recommended power level?