no, they do not. they are "supposed" to store current. Ok, when u have ur engine on, the alternator charges the battery, runs the entire electrical system of your car and would "fill" your cappacitor. So when ONE bass note hits...it drains your capacitor, then your alternator has to "fill" it again. So, it is putting more strain on your system to keep it charged up, and when consective hard bass notes hit...the capacitor cannot keep up, and it ends up tapping into your battery anyways. It does not increase spl, it does nnot make **** clearer...all it does is waste money. peace
NG