Stiffening capacitor

A stiffening capacitor (aka power cap) is a Car audio component designed to provide power during times of peak load. The large capacitor acts as a dampener for the audio power system.

In high power audio applications the amplifier can require more current than can be supplied by the car battery, because of the battery's discharge characteristics. The slow power delivery can result in poor sound quality, dimming of the car's lights, or other electrical maladies. For audio applications that only require short bursts of power, such as a thumping bass line, it is more economical to install a power cap than to upgrade the car's electrical system.

The power cap, usually 1 or 2 farads, is connected in parallel between the battery and the amplifier. Multiple capacitors can be connected with