Call up David Navone at autosound 2000 and ask him about caps genious... I'm pretty sure he has a book you can buy that might clear things up for you... otherwise try a search of the carsound forum as I suggested...

Yes there are many opinions on caps. Just as there are for Homeopathic medicines, ear candling, and communicating with the dead. But none has ever been proven to work. Opinions must be backed with facts.
We are so used to hearing sales pitches for useless weight loss products, magnetic energy bracelets, etc. that just don't work. We are bombarded daily with baseless claims for product that are just a slick sales pitch to steal your money. We seem to forget that when someone makes a claim, it is up to them to prove it. It is not for others to disprove the claims. We just want to believe it because it may make us feel good.

The marketeers of capacitors have not proven how they work to improve a car audio system's performance! It's not up to others to prove that they don't work!

For example:
Show me an oscilloscope trace of DC power to the amp with and without a cap.
Show me a voltage measurment.
Show me a harmonic distortion measurement that shows it has improved.
Show me a noise measurement with and without a cap!

As I posted there is a wealth of information in the RC archives over at carsound including real world test results and some of the graphs you are asking about. If you wish to become enlightened go look for yourself. I've already seen them, and have more important things to do then go digging through old internet posts for someone else who has nothing better to do then argue fallacies.

I think the fact their is so much disagreement about whether they do anything is proof enough that you don't need one.

I have heard of people using them for there headunit to keep power consistent there but again everyone would do it if it made a noticeable difference

AFAIK with the car having an alternator that creates ac power and diodes to cut the tops of those sign wave and make a pulsed rippled dc cap will indeed help "smooth" your dc power. A slight amount of ac makes its way coupled on the dc line which if the power/signal side of your amp is not isolated or the amount is too high can come through as signal noise to your ac fed speakers. The caps will only allow the dc through as well as flatten out those peak ac waves that were cut to create the dc source in the first place.

Plainly, yes from my experience there is no gain in the idea that the cap will be working to supply current in the capacity a battery will but for sq reasons the more capacitance in a power system the better.

Caps are gay

seeing as a cap only store a small amount of power, then needs to be refreshed it'd be useful for music with no bassline, and a loud kick periodically that exceeds your systems power capability

i can't really think of a lot of music like this, any kind of loud bassline would quickly drain a cap and leave you where you started.

Most modern amps utilize a PWM power supply that a cap should cycle faster than unless playing something approaching a test tone at high output levels.

to the OP the reason y ur deck lights dim is because ur prob clipping the crap out of it.. time for a 4ch amp before u fry the deck or u speakers

You have to install more volt power battery in your car. It's happen due to low volt battery...:thumbsup: