1. Quality capacitors DO work - and a few companies continue to offer them. Hint: if it's chrome, comes in a blue felt lined box, has a volt meter, and you can get it for $49 - PASS.
2. In order to achieve the best results, locate the capacitor as close to the amplifier as possible, preferably within 18 inches.
Consider that there are actually TWO voltages available in a vehicle:
1. The output voltage of the alternator (13.8 - 14.4 Volts typically)
2. The nominal voltage of the battery (12.6 - 12.7 Volts typically)
Since capacitors store charge and oppose changes in voltage, here's actually what's going on:
- The capacitor, when connected and charged, stores charge at the nominal voltage of the battery
- As the vehicle is started and runs, the capacitor INSTANTLY is able to store charge at the output voltage of the alternator
- As your amplifier draws current, it takes it from the place of least resistance - in order, that is:
1. From the capacitor (closest source of voltage, and highest voltage potential)
2. From the alternator (highest voltage potential)
3. From the battery (lower voltage potential)
Look at it like this - it's the DELTA between 14.4 and 12.6 Volts that is the deal. Why waste that 1.8 Volts of goodness when you can USE it? Keep in mind that amplifiers "gulp" current based on the frequency at which the power supply operates. This is typically 30,000 to 40,000 times per second.
Since 1986* I have personally used capacitors in my own audio systems and for good reason. I fully expected to see positive results from the addition of a capacitor. I must admit, I was pleasantly surprised at just how much bang one gets from the 1 Farad capacitor. Honestly, there is simply no reason I can think of NOT to use one.
Companies that have elected to sell inferior (IE - CRAP) capacitors have given the word capacitor a black eye. That, along with plenty of mis-information on this topic by keyboard experts, has conspired to paint a non-factual picture of the true purpose of the capacitor in car audio applications. Now that the AD-1 has proven that capacitors do indeed have their place, it's up to you to spread the word.
And FWIW, although I did not mention it in the video, the capacitors in the RF 100 Farad capacitor I showed are carbon based "supercaps" - a technology that was borrowed from the power generation industry. To the best of my knowledge, they were the first of their kind available in the car audio industry. Now, they are but a distant memory.
* Yes, 1986 - that is no misprint or exaggeration! Only Wayne Harris beat me to it and I had no idea who he even was then.