Just thought I'd throw this can of worms out there for everyone to chew on...

What do you think of Caps? In a purely SQ sense, have you used them? What result did you get, how did you have it hooked up (ie: if you have multiple amps, was it only on the sub amp, or prior to the DB to supply both/all amps).

Justify you position ppl! If you think they are a waste of money why!? If you used them before and got a good result what was it? What size cap for what size system did you run?

(You get the picture)

[ January 07, 2003, 20:24: Message edited by: rolli ]

Once all the rest is done, then YES, they can be worth it.

I added one (a Stinger 1fd to support my one 4 channel amp...see link in my signature)) and immediately noticed more pace, enhanced dynamics and a firmer bottom end. It also benefitted other areas higher up the audio band (perhaps a little more air around things) but it was down lower where the value was noticed most.

For sound quality, definitely worth it!

If your electrical system is up to scratch a cap won't offer much benifet, all it is designed to do is store energy and when the electrical system can't provide sufficient power when the amp requires it the cap comes into play then.

If you have major light dimming it can help but if it were me i'd look at making sure your electrical system able to handle the task...Battery, power earth cables alt in good working order.

The reason we use large capacitors in car audio systems is due the the fact that large lead acid batteries have high internal series resistance, meaning that while they can deliver large amounts of current, they do relatively slowly. Capacitors on the other hand have very low internal series resistance and can deliver lots of current very quickly. So, theoretically, adding a capacitor to a system should bring benefits in transient response, ie tightness of bass and midbass as well as going a long way towards eliminating annoying dimming of dash/head unit lights. ( a side benefit) .

In my system you can certainly notice the difference the capacitor makes.

benefits would depend on many things:

*quality and size of cap(s)
*quality and design of amp
*quality of car's electrical supply (battery and alt)
*powerwiring
*demand for power by your stereo (number of amps, how hard you run it)
*demand for power from other car electrics (fan, headlights, etc)
*your ears!

basically, i see them as expensive accessories with limited benefit, if any. a high quality subamp will feature plenty of internal capacitance and be efficient, so the benefits of an additional cap maybe much lower compared with a multichannel amp driving subs (and lacking the same amount of internal capacitance).

then consider that the operating voltage of your car and stereo is within a pretty limited range. the only time the cap will be of use is during sudden dips in voltage/power, as with a big bass note. how much would you expect the voltage to dip for just that? maybe 0.1~0.6V??? possibly; but it's different to say watching the voltage gradually drop over 20 minutes of listening.

so now you have say a 1 farad cap supplying power only during a 0.6V drop. what percentage of a drop in voltage is that? 0.6V out of say 14V...~4%. hmm, that means you utilise ~4% of the caps total storage capacity. 96% is wasted, just sitting there untapped! ok, my figures are just an example, but you will NEVER utilise 100% of the cap's power, coz the voltage would have to dip instantaneously to 0V for that to happen, and it never will (unless you cut the power).

so i think the times they can make a tiny difference is with multichannel amps working hard, providing a very small amount of reserve power that they don't store themselves.

otherwise, they're primarily RICE!

I have caps in my system but am firmly convinced its just audio jewelry(sp). I am yet to hear any improvement to SQ thru adding caps. I have added caps to many systems and couldnt tell the difference. They didnt sound tighter or anything IMO.

I also think if you want to hear an improvement, you probably will, as the minds a powerful thing.
What I always ask myself is could I tell if it was there or not and be confident of picking it everytime (this goes with any component), and I find if Im honest with myself, that with things l;ike caps, stuffing boxes, ro using primo leads, I just cant tell any difference.

When most of these things(devices) are added, i tend to listen harder to hear a difference, which may be why some ppl think things get better, but as I am always asking myself could I be sure of an improvement, I realise that I really cant hear a difference. I guess I listen to so many systems that I have become skeptical about whats real and whats perceived, as I try to avoid falling for perceptions and rely on what my ears tell me.

If you beleive something works then do it, as its all about being happy with your system but personally I prefer to be sure something does improve things before I hand over my hard earned, rather than just hoping it will or relying on what other beleive to be true. If something is that hard to quantify its results, then often those results are just what you want them to be, as it should always be night and day difference IMO
Just my $0.02 worth
peace
Cyberpunky

i'm with cyberpunky on this one ... i added a 1 farad stinger capacitor to my system, played around with various configurations and connections, and have not noticed any difference whatsoever ... try as i might, i now just can't justify having bought the darn thing (!), and in hindsight i think the money would have been better spent elsewhere

one thing ive always wanted to do is a blind listening test (a/b comparison) with a system having the cap connected, then disconnected, to see if there was an audible difference. at this stage of my car audio experience, i havent heard caps making any sonic difference to my system or anyone elses - though that doesnt mean they dont, because i havent tested it either way, so i am still open to the idea. for me, i have a 1F stinger HPM cap in my system, primarily to eliminate diming lights and things like that, which it does very well.

also, when i pop the boot, one of the first things laypersons ask is 'WOW what does that big cylinder thing do!' hahaha

that said, the electrical system of a car is a pretty terrible thing for providing stiff and consistent electricity, so anything one can do to improve it may be seen as worthwhile.

They won't make any difference to the SQ of your system. For it to make an audible difference you would need a really poor electrical system with really crappy amps. Even then you would need a really good cap. Caps can't store much energy and most of what they do store isn't utilised in our amplication.
Most modern amplifiers have enough of their own storage capacity to handle any peaks in the music that may occur. And if the amp has a regulated power supply (nearly all amps these days) then you can forget about it making any difference.
However they can be used to help stop that annoying light dimming situation.

Whoa.

some interesting theories.

I am fortunate enough to own a car with a standard voltage meeter in the dash (R30 Skyline). Running my Jaycar 5 channel hard through a 15" produced SIGNIFICANT intermediate drops in input voltage. The "dimming of the lights" going to extreme lengths on one occasion, when I actually managed to stall the car at a set of lights.

Although this may be considered a result of the type of music I listen to, it somewhat alarmed me. Significant current debt, as hutch mentioned, results in clipping of the output signal, which is bad for SQ and even worse for speakers. since putting an Altronics cap inline, I have noiced a significant firming of the bottom end, and improvements in the top, which I attribute mostly to the fact that im running 5 channels through the same amp device.

short answer = dimming lights baad. Capacitor = Good.

As some of the guys have said, if you have very good electrical system (eg. high current alt, lots of batteries a short distance from the amps etc...) a cap will not help much if at all. But if your running a small battery and not getting enough power, a cap will help keep current flowing into ur amps and keep the current smooth without any spikes.

I installed a cap a few days ago, previously i was dipping below 12 volts on huge bass notes which concerned me....

Although it hasnt made an audiable difference because as was said earlier, higher quality amps have a decent enuff in built power supply to handle these dips in juice... however i thought i'd put one in anyway to help stop it...

It has worked in smoothing out the lows and has MAYBE tightened the bottem end up a little bit, but something tells me its simply a placebo effect... but hey, its still a difference isnt it??

but yeh, once u upgrade ur battery, sure get a cap, they look cool and also act as apretty good safety net agianst damage to ur amps..

In car audio, the cap maybe to store some line current

But in typical audio
and it certainly will apply to car audio methinks
the "filter" capacitors are used to smooth out the DC ripple on the power supply.
If theres any ripply on the supply. that ripple is transfered to the output of the amp, resulting in distortion
In the AC/DC rectifycation in the altinator, there is minimal filtering if any provided, so for any SQ app i recommend a capacitor be fitted.

yeah, an often unknown benefit of power capacitors is that they 'filter' your power line, from alternator engine noise and other nasties - in much the same way as those little $15 condensers you buy to stop alternator whine work.

the power cap is simply a VERY big version of a noise filter

The problem is, you want caps *after* the power supply, to smooth the ripples in the high voltage rails. Which is just one of the things that top end amps often have better, a good PS, with a largish cap bank.

In short, unless your electrical system sucks, shouldnt need a cap. I've seen a single good battery in the boot added to a system with a lil over 2kw (running rather flat out) with no dimming at all of lights.

Im running a 900wrms sub amp and i have about 5m of 4awg power wire(soon upgrading to 0/1awg). I have a 800cca bat up frount and even with all the chasy grounds upgraded my amp still ran hot. I installed a 1farid Rockford Fosgate power series cap and it drematicaly decreased the temp of my amp by about 30 degrees. They would take skin off your fingers in the middle of the night but now they run stone cold and my subs magnet gets toasty warm:) I dont think it made any audable differance but then if i could switch between the two instantly i probably would(you know how your comparing something form 1/2hr ago to something your hering now its not any way to compare)

The 1.5 farad cap I installed made a dramatic difference to the volume that my sub could reach, but that was in my case, a lot of people say they do nothing, but for me it was the best money I ever spent!

The debate on caps is a little like a debate on tyres.

Whilst they all look pretty much the same they do not all perform the same.

A test in Car Audio and Electronics some time ago was very interesting.
They stated that some of the so called leading caps were a waste of time and money.
In fact some of the caps tested when they removed the outer sticker found another brands sticker underneath!

Problem is, people in Australia want caps that look cool and cost little, this is always a recipe for disaster!

Phil K

Can someone indicate to me how you guys are wiring in your caps, cos thats also a consideration. ive always though you put + from battery onto the +ive cap then the +ive cap goes to amp, the -ive from the cap just goes to earth?
Ive heard some ppl just wire them +ive from battery to +ive cap, then -ive cap to amp.

could someone scan and post that article? it'd be a good read.

I was going to say, wouldn't I get the same, or a better result from just wiring another battery in line?

NO.. Because caps work when the alternator can no longer supply enough current (when the voltage starts to drop), when the voltage is higher than the battery voltage. As soon as the voltage drops to the battery voltage, the cap is useless and the battery starts to supply current..

A second battery will actually increase (as its more load on the alternator) your voltage drop, until it drops to the voltage of your batteries..

The problem with caps however, is due to the very limited voltage range, as well as the amount if internal resistance and inductance, very little of the capacitors total capacity is actually used..