The truth about caps

[talnlnky]

The following is taken from a PDF file I have. Richard Clark pretty much invented the trend of using the big capacitor for car stereo issues. Last I heard he worked for Monster Cable, I believe he worked for MTX at one point too. He completely denounces the worth of the audio cap in a stereo install for voltage purposes.

"This is a real world test that was measured by Richard Clark on a Audio Precision unit
to portray what happens with a typical capacitor install.
The main point for those who point out the obvious differences between the Red (cap
installed) and yellow (cap not installed)…how much of a dB difference is .1-.4 volts in
terms of music? And do you feel you are going to hear this within a car?
On with the explaination:
Dark Blue curve---
For our first test we played the system with the engine off and no cap. The result
was the purple trace at the bottom. We played the system as loud as we could get it
that seemed to produce no audible distortion. This was track 30 of the IASCA disc. It
starts off with fairly low level sounds for the first 34 seconds. In order to insure the
electrical system was stable we did not start the measurement until we were 20
seconds into the song. This means that our 0 starting point is :20 on the CD counter.
The battery was able to maintain it's voltage just below 12.5 until the loud bass hits
at 34 seconds (14 seconds into our chart) At this time it dropped to about 11.5 and
had a few large variations due to the music. According to the computer calculations
(third chart) the average voltage for this test was 11.7volts. This test was done as a
baseline for the following tests.
Yellow curve—no cap
For this test the volume was left as it was for the baseline test. The engine was
started. Notice that at low volume the alternator was able to maintain about 14
volts. When the loud music hit the voltage dropped to about 12.5 where it remained
except for a few short moments where it actually climbed back to over 13.5 volts.
The computer averaged calculations for the average voltage during the 100 seconds
of this test was 12.973 volts.
Red curve—cap added
This test was identical to the previous test except the cap (15 farad type) was added
6 inches from the amp with 4 gauge wire—no relays or fuses. The red curve seems
to overlay the yellow except that the actual peaks don’t rise as fast or as high during
the brief quiet moments. I feel this would be due to the alternator having to recharge
the cap. The voltage on loud passages hovered around 12.5 volts. The computer
averaged calculations for this test show the average voltage to be 12.878 volts. I see
no meaningful differences with or without the cap. I certainly don’t see the voltage
sitting solid at 14 volts.
One note I might add is that this was a two thousand watt system driven right to
clipping and the average voltage stayed above 12.8 with a stock 80 amp alternator.
Under these conditions the battery would never discharge!
The green and light blue curves were done just for kicks while we had the system set
up. In both these tests we turned the volume up until the system was very distorted.
This placed a severe load on the alternator and caused the voltage to dip as low as
12 volts. The curves seem to follow each other so closely that unless you have a
good monitor it is doubtful you can tell there are two curves. The average voltage for
these two curves were both 12.277 and 12.295 volts. If this volume were sustained
for very long periods of time this battery would discharge"

[whoguy]

Thought that'd be the case.

The quality of the Power AMPS internal stepup voltage SMPS is really what counts....i.e... High Current and Voltage stability.

[1NZYaris1]

so the final word would be do not use cap's and save your money for a bigger alternator.

[cali yaris]

It's like Richard Holdener of the audio world

[Spades]

but, the question would be, on a lower wattage system with a average cap where you were playing music with a consistent hit, that would require bursts of energy for the subs, would a cap be a bad idea? regardless of how it affects the alternator...because, the alternator WILL be taxed by lots of stereo goodies regardless of the alternator. i mean, you are still draining the battery.

i was under the impression all a cap was for was to reduce strain on your battery that causes headlights to dim as it sucks a large amount of amps with a quick bass note. a cap isnt meant to relive strain on the alternator, i thought it was meant to aliviate the battery.

technically, no matter how powerfull the alternator and the battery(batteries?) the alt is still going to have to charge the batteries at some point, you are still using the energy when you are pushing your amps to clipping...no matter how many caps you have, that alt will still be taxed.

i guess maybe i mis understood what manufacturers were claiming their caps could do. I always assumed that everyone understood a cap is for a faster harder hit of bass and would keep your battery alive longer and eliminate headlamp dimming. i guess i never heard of a company claiming their cap relived alternator strain.

[pariahdecss]

Yes - that would be my question - I used a cap in the past to stiffen the power supply to my amp(s) so my headlights wouldn't dim - not for any audio quality or dynamic range improvement - Is this still a valid use?

I am about to dump a new system into my 09 LB - and I do have an old 1 farad Lightning Audio CAP I was going to stick in there just for the heck of it inline with my new PDX5 amp

[wsladaritz]

I use a 2 farad cap for my subs. I only have it to keep my headlights from dimming on hard hits. And i severely abuse my system, almost all the time loud and angry and I almost never turn it off when I'm in the vehicle. I think it makes a difference for dimming lights. I never even thought it would or could improve the sound quality or loudness.

[talnlnky]

Originally Posted by Spades

but, the question would be, on a lower wattage system with a average cap where you were playing music with a consistent hit, that would require bursts of energy for the subs, would a cap be a bad idea? regardless of how it affects the alternator...because, the alternator WILL be taxed by lots of stereo goodies regardless of the alternator. i mean, you are still draining the battery.

i was under the impression all a cap was for was to reduce strain on your battery that causes headlights to dim as it sucks a large amount of amps with a quick bass note. a cap isnt meant to relive strain on the alternator, i thought it was meant to aliviate the battery.

technically, no matter how powerfull the alternator and the battery(batteries?) the alt is still going to have to charge the batteries at some point, you are still using the energy when you are pushing your amps to clipping...no matter how many caps you have, that alt will still be taxed.

i guess maybe i mis understood what manufacturers were claiming their caps could do. I always assumed that everyone understood a cap is for a faster harder hit of bass and would keep your battery alive longer and eliminate headlamp dimming. i guess i never heard of a company claiming their cap relived alternator strain.

A cap will help in a car that already has an alternator that can keep up, and still has a bit of headroom, along with a decent battery. HOWEVER, if there are any symptoms of an electrical system that can not keep up, then it will do more harm than anything else.

Symptoms could include, weird rpm fluctuations, dash or headlight dimming, slower than normal starts when you turn on your car.



There was another write up that was pretty good that I no longer find anymore, it showed the math behind the discharge of a cap... Basically It came down to a 1farad cap would only be able to power a 1000w amp for something like 1/10th of a second, and then its power is used up, and then becomes a drain on the system... That is where Richard Clark's article picks up. If a cap is being fully discharged, you've got bigger problems than a cap can fix.



To answer the question about headlight dimming... yeah, a cap will make it appear that your head lights don't dim as much. The reason for that is because your lights won't be getting as bright. They will stay dimmer, longer, and thus you won't see as big of a fluctuation, because there will be a constant drain on your electrical system.

[wsladaritz]

Originally Posted by camelll

http://en.wikipedia.org/wiki/Capacitor

They work. Years and years of use in every aspect of electronics prove this fact, I cannot believe you are arguing that capacitors don't work. If they don't work then remove them from every electronic device you own and see if it still works.

lol, that right there is enough hard evidence for me to keep my cap! AMEN!

[supmet]

Originally Posted by talnlnky

A cap will help in a car that already has an alternator that can keep up, and still has a bit of headroom, along with a decent battery. HOWEVER, if there are any symptoms of an electrical system that can not keep up, then it will do more harm than anything else.

Symptoms could include, weird rpm fluctuations, dash or headlight dimming, slower than normal starts when you turn on your car.

Well I've seen a cap PREVENT headlight dimming, and the only way it could account for slower starts is if you turn your car off in the middle of a bass hit(but if you care about your car you'd be turning your stereo off before turning the car off)

Originally Posted by talnlnky

and then becomes a drain on the system...

Please explain the mechanics of phantom energy to me. Where does this drained energy go? (besides resistance)

Finally, you should release these results to the thousands of stereo shops that recommend caps. Along with all those people winning stereo competitions. Oh the people making the caps will probably want to know too.

I think I'm gonna stick with the millions of articles that say caps work, rather than the ONE that says they don't.

[talnlnky]

Originally Posted by supmet

Well I've seen a cap PREVENT headlight dimming, and the only way it could account for slower starts is if you turn your car off in the middle of a bass hit(but if you care about your car you'd be turning your stereo off before turning the car off)




Please explain the mechanics of phantom energy to me. Where does this drained energy go? (besides resistance)

Finally, you should release these results to the thousands of stereo shops that recommend caps. Along with all those people winning stereo competitions. Oh the people making the caps will probably want to know too.

I think I'm gonna stick with the millions of articles that say caps work, rather than the ONE that says they don't.

I have yet to see a single SPL vehicle at world finals run any caps. They have crazy sponsorships that allow them to pick them up for cost. There is a reason why they don't run them.


All the non-believers can go to some actual car audio forums, elitecaraudio.com, and soundsolutionsaudio.com are two decent forums.

Car shops make money on them, they make all their money on accessories.. Decks and speakers bring them almost no profit, its connectors, caps, and wiring that they get their profit from. Why stop selling a product that pays the lease on your building?

there are also articles, RECENT ones that say likewise, Also, it takes NO education, not even a highschool diploma to open a audio shop, or to be the head installer. Try talking to an electrical engineer who has actually studied the science behind the problem, and is familiar with car electrical systems. If nothing else, adding a cap to the electrical system adds two more connection points which add resistance, and thats before you even add in the internal resistance of the cap itself. STORAGE MEANS NOTHING if the power plant can't keep up. Eventually the storage will run out. CAPS are storage... and a very small storage at that. Anything more than what is built into the amplifier is overkill, and will not help you at all unless you already have a power plant (alt) that can keep your storage (bat) 100% full 99.9% of the time already. If you fit that situation... then you won't have significant voltage drops at all, but you will still have very minor fluctuations (talking in the range of a tenth of a volt or less). In that situation... yes, a cap will help stabilize the voltage the way it is supposed to.

But, is +/-.05v worth $100 or more per farad? People who have light dimming are most likely seeing dips of 1.5v or more already, just for refrence.

For those who swear caps stopped their lights from dimming... did you have volt meters recording your voltage real time? Did you have light sensors watching the output of your lights... did you do A/B comparisons?

If not, then admit that your "real world experience" is very possibly incorrect, and flawed with bias.

I can't think of a better quote to describe this situation other than...

"We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology."
-Carl Sagan

[talnlnky]

Originally Posted by camelll

My thoughts exactly about you saying caps don't work.

The cap can only be charged to the max voltage of the alternator, so if your alternator is already strained then it can become an extra strain on the system. If you listen to music that is just one continuous bass note then yes a cap is no good. This is not the norm for end users. For a car audio competition then yes a cap would be useless, that is why they don't use them. For the everyday average user a cap is beneficial, you can never have enough capacitance.

You are living in the late 80's early 90's on your stereo advice. Most new caps have a ESR (Equivalent Series Resistance): < 0.0015 ohm, figure that into your equations.

I don't need a volt meter or a light sensor to know that my lights are not dimming since I installed a cap. For the record though I do have a volt meter that is hooked up in the car in the form of scangauge. Your thinking is what is flawed and very biased. I have given multiple instances of proving caps work, you have provided a Richard Clark test that was done probably 10 or 15 years ago, done with a audio competition cd that is continuous bass throughout the hz frequency range.

As far as your comment about they only reason they are still selling them because they are bread and butter, that is b.s. Show or tell me of some products that don't work but have been around since 1782.
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Thats what I thought!

http://www.caraudiomag.com/technical...ors/index.html

"Whatever you want to call them, EDLC, stiffening, supercap, or ultracap, it appears that they aren't of much help for the SPLer, except to stabilize the system voltage for the head unit and signal processors. However, for clean audio and improved transient power, these capacitors can extend the battery and improve the audio performance, including reducing harmonic distortion in the low frequencies." NUFF SAID.

I suppose the people at car audio magazine don't know what they are talking about either, maybe they are getting kick backs from the bread and butter shops make for selling the caps!

the 1 farad cap hasn't been around since the 1700's...and especially not marketed for the car audio industry. There are plenty of items that exist that don't work, but sell. There are thousands of "lose 4 inches off your waist in a week" products out there, as well as beauty products which claim to reduce the effects of age on a woman's face.

From my experience, most people with subs in their cars have at one time or another taxed their electrical system too much. Most people who have subs fall in the category of 16-24 yr old males, and too often than not, try to put as big of an amplifier as they can in their car without doing any math to see if the car can handle it.

For people running less than 600rms TOTAL in their car on a stock electrical, yeah, a cap probably won't hurt. But i've met more people who run more than 600rms to their sub(s) alone, than not.



Oh yeah... and about your statement about caps not being a load on the system... why is it then that if you leave a cap for a day they lose their charge mysteriously... You charge something, and instantly its already losing its charge, even without using it.


My statement remains, caps are the icing on the cake, upgrade the alt, all cables, and battery before even thinking about a cap.

[Alien Mantis]

To be honest, both of you are right.

A CAP will not make up for an overloaded electrical system.
But a CAP can help a system that is close to its maximum capacity.

And you need to match the CAP to the system requirements.

You don't need a big CAP if you are running a modest system that is close to the alternators output.
A 2 Farad CAP would be fine.

If you are running big amps, you will need to upgrade the alternator.
Most Alternators are around 80 amps max output. And you don't want to be pushing them at their max limit all the time. It will burn them out quicker.
It is silly to put a bunch of big amps in your car, and spend all the money to upgrade the electrical system, when you could run less CLEANER power and still get good results.
ALWAYS run the LEAST amount of power you need to get the job done.
People with 2,000rms watts or more of amps in their cars are crazy.
If you are doing SPL competitions, I can see it, but for the average music lover, 800-1,000rms total power is PLENTY.

CAPS are only meant to provide a momentary surge of power to compensate for the amp drain hit during music. (Such as kick drums on the bass amp.)
When the amp spikes, the CAP tries to fill the energy hit. The CAP has to be able to recover in between the spikes in order to continue to be useful. The alternator/battery is responsible for that task.

MY experience has always been to go with speakers that have a high sensitivity rating ( greater than 90db at 1 watt ), very CLEAN amps, heavy gauge wiring, and the least amount of SUB to get the job done. A single 10" sub in the correct enclosure can almost always get the job done. 10's are better than 12's because 10's are more accurate.
12's require more box space, and more power, but they don't hit as hard as 10's.
Also... use Dynamat! ( or any other good brand )
Most cars do not have adequate sound dampening. ( Yaris especially. )

AND.... if your total system wattage is around 800-1,000rms with a stock alternator... use a CAP.
It will make a difference.
If you are pushing over 1,000 watts, upgrade the alternator AND use a little larger CAP.

If your alternator is strong, ( over 80 amps max output ) , and your system is less than 800rms watts, and you don't blast it at high volumes all the time, then you might not even need a CAP.

Bottom line is: do you want clean powerful music to listen to in your car, or do you want other people to hear your "boom" from a half a block away?
Totally different situations, that require totally different solutions.

I'm not into the "boom". I like clean music IN the car.

[ChinoCharles]

A capacitor is more cost effective than a high output alternator. Actually, that is an understatement. It isn't even close.

Also, most audiophiles don't go for SPL. I say a cap is still a great solution for someone who puts out slightly more wattage than his or her eggmobile can handle.

[Alien Mantis]

Originally Posted by ChinoCharles

A capacitor is more cost effective than a high output alternator. Actually, that is an understatement. It isn't even close.

Also, most audiophiles don't go for SPL. I say a cap is still a great solution for someone who puts out slightly more wattage than his or her eggmobile can handle.

I think you might be confused.

A CAP is no substitute for the correct alternator.
A CAP does NOT create energy, it only "stores" it.
The Alternator is the only thing that creates energy.
Same thing with the battery, it only "stores" energy.

And... a CAP is NOT a solution for a system that requires more energy than what the alternator can produce.

A CAP smooths out the energy spikes. That's it. It can't do anything else.

You can do a simple test on your own system:
Start your car, and turn on the headlights.
Now turn on your stereo system and crank it up to the normal max level you usually listen to it at.
Raise the hood, and go to the battery in the engine compartment.
Connect a voltmeter to the battery terminals.
Raise the RPM's up to around 2,000.
Read the voltmeter.
You better see 14volts+.
If you do, let it go back to idle.
Check the voltage drop.
It better stay at 13.8 or higher.

It's better to measure the "current flow" and not the voltage, but the
voltage test is simple. Anyone with a common multimeter can take a voltage reading.

Keep in mind, if you live in a hot climate, and run your A/C all the time, then you also need to turn your A/C on when you do this test.
An A/C system can pull alot of amps and put your total amp draw over your alternators limits, when used with your stereo system.

A CAP is not going to fix an overloaded electrical system.
It will only smooth out the energy spikes during music play.

I still recommend using a CAP, especially if you run higher power / multi-amp setups, which most people do.

[ChinoCharles]

So what if your headlights dim to 75% of their normal brightness every time your sub hits? Say "get an alternator" and I'll throw something at you. I only need a CAP!

[Alien Mantis]

Originally Posted by PK198105

the best way to gain more energy is to connect an extra battery and change the alternator to a heavyduty one, this however isn't cheap and adds weight to the car.

True.

With most compact cars, it's hard to find a good place to mount a second battery. Some people like those deep cycle yellow-top Optima batteries.
I prefer the red-top Optima, but either way, those batteries aren't cheap!

[Alien Mantis]

Originally Posted by ChinoCharles

So what if your headlights dim to 75% of their normal brightness every time your sub hits? Say "get an alternator" and I'll throw something at you. I only need a CAP!

Remember, I never said you did anything wrong!

The CAP worked for you, so obviously you needed it.