The capacitor is connected to the positive power line to the amplifier, and then grounded to the vehicle chassis. When initially connected, the capacitor will very quickly charge up to the voltage of the vehicle's battery. So quickly, in fact, that a large spark will occur unless a small resistance is used to slow the rate of charge. More on this in a moment.
Low frequency causes the output transistors in any audio amplifier to remain on and flowing current to the speakers for a longer period than midrange or high frequencies. Low frequency therefore creates the greatest current draw in any audio system. As the source of low frequency in music is usually a drum or bass guitar, the low frequency is mostly in short bursts, or "transients". So subwoofer amplifiers generally draw the most power from an automotive charging system.
This power "reservoir" in the capacitor only works to a point. If the power draw from the amplifier or multiple amplifiers demands so much power that the alternator can't bring the charging system and capacitor back up between bass transients, then reduced bass response and flickering lights will again occur. Adding more capacitance may help, but an alternator with a higher current rating would be a better solution.
Technical Details:
3.5 Farad Capacitor
Digital Red 3 Digit Voltage Display
Chrome Plated Battery Post
Lightning LED
----------------------------------------------
Package Content: 1XAT-5.0 Farad Capacitor