the basic definition of a capacitor is a cell designed to hold a specific amount of charge for only as long as an outlet for energy escape is not available. The very instant an exit path is available - the capacitor discharges its entire charge. Once discharged, if given supply of "re-fill" juice, it wil instantaneously demand a complete recharge from the source supply. Capacitors in car audio are VERY, VERY, VERY often used FOR THE WRONG REASON(S). To put it simply - if you do not have an adequate supply source - the alternator in the case of vehicles, a capacitor is nothing more than a further drain on the overall electrical system. Capacitors, when used properly, essentially shorten the path between the amplifier(s) and the 12v +. As a side note - a 1 farad capacitor fully charged can easily kill a person, so be careful.