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I think most of them are sold to noobs with beginner set ups... just to get money off them? It's funny that most of US here can't explain in DEEP DETAIL what they do and when to use them but a lot of beginners have them. Maybe they're misinformed but then again so are a lot of us.

And the fact more than one person agrees does not make it a circle jerk, it makes it a bukkake scene and you're in the middle ;)

Chick took 3 shots of Jager, and then, pissed in my mouth..

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Haha I didn't look that up- I'm in my junior year of EE. Capacitors all have a time constant that's dependent on their actual Farad rating. The larger the rating, the longer it takes to charge and discharge. It's kind of intuitive, but having even like a 5F capacitor in your system won't provide a discharge and keep your voltage constant for that long.

2016 Subaru BRZ | Sony XAV-AX100 | Rockford Fosgate DSM 4080 & DSM 40ix |

On 6/6/2012 at 6:32 PM, 'LZTYBRN' said:

3. Don't put speakers outside the car unless you are the ice cream man.

My feedback thread

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Holy Cow there's a bunch of mis-information in this thread about caps. Caps work - period. But how? Simple . . . capacitors do TWO things:

1. Store charge

2. Oppose changes in voltage

Now, both of those things sound mighty nice to me. To understand how a cap benefits a car audio system, one has to first understand that there are TWO separate voltage plateaus available in an automobile:

1. Running - With the alternator charging, voltages will typically be from 13.8 to 14.4 VDC

2. Not running - With the alternator IDLE, voltages will typically be from 12.0 to 12.6 VDC

I'll take the higher of the two any day. For UNREGULATED amps, this allows them to draw MORE current therby making more power. For REGULATED amps, this allows them to draw LESS current to make their rated power. Either way, it's a WIN for you. So, how do we ensure the higher of the two?

Again, simple. With the vehicle running, consider the DELTA between what the alternator can make and what the nominal voltage the batteries can provide is. For this example, lets assume 14.4 VDC - 12.6 VDC = 1.8 VDC. When we exceed the current output capability of the alternator, it's voltage output is compromised. In some cases, heavy demands of amplifiers can far exceed the current capability of the alternator, leaving us with only the reserve of current within the battery. But, car batteries weren't intended to power amplifiers . . . they were intended to start cars [battery = Load with vehicle running.] A really fresh car battery can do this for a while, but given that we're exceeding the output capability of the alternator, it's charge isn't getting replenished quickly enough - need about 13.0 VDC minimum to allow charge to flow back into the battery.

A properly sized capacitor will change the rules. With the vehicle running, it stores charge at the higher voltage plateau - 14.4 Volts. As the amplifiers demand current, it will flow from the place of least resistance . . . Ohm's Law tells us that happens to be the place with the highest voltage. That will be in order:

1. The capacitor (closest)

2. The alternator

3. The battery

Ideally, you've selected the correct size capacitor for your system's needs. And . . . that "30F" cap that sells for $59 in a blue velvet box with chrome and a big blue LED readout is just a glorified volt meter These devices have ZERO benefit. There is a reason why quality capacitors cost money, and ours are no exception. These are the facts:

1. A 1 Farad capacitor can store and release 72 Joules (watt*second) of energy at 12 Volts.

2. Said capacitor can charge and discharge hundreds of times faster than an automitive battery of any kind.

3. Capacitors present nearly no load to a properly set up charging system.

4. Automotive batteries require 7 to 10 amps of current EACH to allow charge to flow into them.

5. Capacitors work GREAT for every day street systems.

6. The benefits or capacitors are negated in SPL competitions.

For best results, I recommend locating capacitors within a foot of the amplifier - as in, no more than 12 inches of wire between the capacitor and the amplifier. The further away from the amp they are, the less of a benefit they offer.

I have used them my systems for a very long time . . . since about 1986.

old school quote.

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dont take this as sarcasim any way snafu.

I will be soon running 2 amps for my subs. 3000wrms by 1 @ 1 ohm each. They will be ran daily at around 15.5 volts at around .7 ohms.

My amps will put out 4500wrms by 1 @ 1 16.5 volts.

I will soon have a irragi alt and voltage regulator whenever he gets back to me, just waiting on Dom.

Ive also seen one of my amps draw over 450 amps at ruffly .75-1 ohm.

So are you telling me that running a big capacitor will benifit me more then lets say 4 Powermaster 3100s or 4 kinetik hc2400s?

All I know is anything below 12.5 volts I am at risk of frying mosfets when the amps are ran at 1 ohm.

You really didn't give me much information to go off of . . .

- Your amps are obviously unregulated as they can produce more power with higher input voltage . . . maybe T3ks?

- What topology are they? (Class D?, bd?, A/B?) OR, what are their efficiency ratings?

- How much current at 14.4 volts are you paying Dom for?

Some simple math with your 3,000 watt Class D example at 14.4 VDC on sine waves would be:

3,000 / .75 = 4,000 watts Input required x 2 = 8,000 watts input

8,000 / 14.4 = 555 amps of current

Let's say your amps require 17 feet of power wire between them and the batteries and another 5 foot between them and the frame (chassis won't cut it here) for their grounds. To get 555 amps of current to your amps at 14.4 VDC, you'd need:

Big Wire:

- 1/0 AWG wire has .0001 ohms resistance per foot - 22 foot of it will have .0022 ohms of total resistance

- 555 amps through 22 foot of 1/0 . . . 555 x .0022 = 1.22 Volts drop in the cable alone

- 4 runs of 1/0 AWG . . . 555 x .00055 = .30 Volts drop in the wire - mo' better


- 300 amps at 14.7 volts . . . remember, we lost 3 tenths of a volt in our four runs of 1/0 AWG . . .

- 2 required

Now, if we add batteries, these need 7 to 10 amps of current each to allow charge to flow into them . . . I'm not seeing the benefit with the car running. But, if you wanted to jam this system with the key off then you'd need 'em for sure. Look at the AH rating on the battery you're shopping for. On music, these two amps would require roughly half of the current they require on sines . . . let's say these batteries had a 65 AH rating.

555 / 2 = 277.5 Amps

277.5 Amps / 65 AH = 4.3

So, you'd need 4 to 5 batteries to play this system wide open on music for ONE hour. After one hour, nominal battery voltage would be somewhere around 10.5 to 11 VDC.

And . . . these 4 batteries would require 40 amps of current to allow them to be charged with the vehicle running . . . better get Dom to up those alts to 350 amp models . . .

Ain't nuthin' free . . . Incidentally, this is a case where capacitance just can't cut it. The amount of capacitance a system this size would require would make it cost prohibitive, but if you could swing it, two of our 100 Farad caps of old would certainly help.

Now - where you're getting 16 volts DC you'll have to share . . .

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Can you prove that?

I can prove that dollar for dollar there is something more effective than a cap for daily use, but not that the capacitor itself is detrimental :unknw:

I'm all ears . . .

XS Power D1200 - 44Ah $216.99

Rockford Fosgate RFC10HB - 10 farad, $229.99

1 farad is 1 amp second


44Ah x 60mins/1hour x 60seconds/1min = 158400 amp seconds - equivalent to 15840 of the Rockford capacitors for 13 dollars less.

And lets say that you exceed your alternator's power output at a certain frequency - say for 3 seconds in a song, and you exceed it by 20 amps The capacitor would be discharged in a half second, making it not only useless for supplying power, but also an additional drain on the alternator as it charges back up. While the battery can supply that power and although it will take some power to charge itself back up, it still has some "reserve" power left over to aid in keeping the voltage steady while the capacitor just fell flat on it's face, per-se.

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Everything you need to know. Documented with real math and real scientific experiments

Edited by 79Bronco
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Source: Parrot Asteroid Smart

Processor: Digital Designs X1

Amps: Soundstream Ref 4.920 + Soundstream Ref 4.400 + Soundstream DTR 3400

Front stage: Hertz 165xl + HL 70 + HT28

Rear fill: Hertz 165xl

Subs: 2 SA-12's

3-way active ftw

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I've been told that capacitors helps clean dirty signals.

Here's an interesting story:

When I went to Lockheed Martin, which develops global aerospace, defense, security, and advanced technologies, I encountered a guy who installed a huge, and probably an extremely expensive surveillance camera on an H2 Hummer. I asked about the electrical, and he told that the Hummer consisted of a 320 amp alternator, audio cables, and batteries(didn't mention brand), and he said to help keep the signal clean, he installed a capacitor for that. Already having a strong electrical system, he obviously didn't use the capacitor for electrical issues.

2003 Kia Sorento

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Best score: 150.2 at 40hz (3k, 2 Custom HDC3 15's) Usaci style(door open, in the kick)

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Here's my Capacitor story

so I got my first cap when I had stock alt and yellow top under the hood running 900watt xplode amp..

I got SHC6030 Stinger 30 Farad Cap and with the electirical I had at that time it was the worst idea ever.. I didnt know too much about speakers etc and I thought bigger

cap gonna give me more power.. unfortnatelly it was completly oposite.. bass hit better but for only first couple sec and than it was getting worst and worst since the alt

couldnt produce enough power to recharge it.. than i upgraded my battery/xs 3400d and 180singer alt.. and I cannot say now if the bass would be better with or without

the cap but voltage on my battery on full tilt never drops below 14 (usully it stays between 14.1-14.3 depends how my car "feels like" lol) and from reading on the cap

voltage goes 14-14.6 - I can regulate it on higher voltage but I kinda dont belive it.. I dont wanna sell this cap since I might run it on my mids/highs amp after I get another

battery in my trunk...

sometimes Loud is NOT pretty

Sounds like its safe to go ahead and bend that ass over.

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