Rather than tag this post on the end of the previous thread, I started a new one. There were some off-topic discussions in the original thread that might clutter things up. And my apologies for taking so long to do this.

Anyway, in the original Pondering Power thread some of us had talked about doing some tests to try and determine just what a stiffening capacitor did to an audio system. I finally did a test this weekend, and it was very interesting.

Even though I don't have a big amp, I was able to consistently measure an increase in amplifier output power when a capacitor was added to my test system. Unfortunately, (depending on your perspective) the difference was minimal, so much so that I don't plan on buying any capacitors anytime soon.

It's way too much info to post here, so check out the Stiffening Capacitor Test I've posted on my Web site.

 

I think the capacitor is there to prevent fading instead of additional power that I assume you're expecting to see. Try running the amp just under its limit and see the difference the cap makes. It made a signiticant difference in the low end response on at least two systems I've installed.

There is something there, maybe we need to stand back and look at it in a different way. You can't add capacitance to a system and not affect that system.

 

Ok lets say this. In the S2000 if you are not running subs you probably do not need a cap. If your running a sub that draws less than 40 amps you probably do not need one.

You setup your system to simulate and test the amps output. What were your driving?! I didn't see a speaker in there.......or atleast a sub that would suck up all that amps output!

What you really need to do is get a amp in your car that is LARGE enough to really put a drain on the car. Your talking a sub amp that needs a 60 amp fuse as well as a mid/high amp that draws 40 amps and put in your best bass ridden CD. You should see lights dimming and such.

Then install yourself a 2 farad cap. You will see that light dimming gone and a whole lot more bass!!! Honestly a 50 watt RMS amp is just not going to draw enough power to really test a system. Since you are not doing the test in a real car its hard to simulate the batterie and alternators charge.

I am not a EE do not profess to be an EE I do how ever know enought to comment on this subject since I have been installing real world NON TEST BENCH systems for over 10 years. I have upgraded batteries(got more bass) upgraded to multiple caps(more bass) because the charging system just can not keep up with the INSTANTANIOUS need for GOBS AND BOGS of power.

I chatted with my installer about this subject and he told me a buddie of his had a meter to test the draw on the batt. He said that with a decent sized system with say a 60 amp fuse would actually draw at a peak bass hit over 100 watts! This would not pop the fuse because it was only for a split second.(not enough to heat the element up) This is when a cap gets tested. The internal caps can keep up only so much then it bottoms out and tries to get the extra from the batt but it can not discharge its power as fast as caps can. So the bass flattens out like hitting a fuel cutoff.(it has more potential but its held back)

Sorry to blast you like that but here I believe MacGyver should go over your findings with a EE's point of view.(did I just say that)

 

Remember in the previous thread I was trying to point out that the cap isn't for increasing headroom, its for maintaining it. I concur with Pinky, dump a large amp in there and watch your headlights do the "Electric Light Parade" simulation. This will also extend/preserve the expected short life of the stock alternator.

 

Wow, excellent job! My apologies, as the starter of that thread, for not having done this yet myself. I couldn't have done as good a job for sure...

While I agree with Pinky that 50Wx2 amplifiers aren't the types to traditionally necessitate capacitors, the power supply used (13.5v 24a) is less than 1/4 the power provided by an S2000 alternator. In the initial test with the 24 amp power supply, the capacitor provided no benefit. If we were to extrapolate the amp's draw and power supply's power x4 (then subtracting a bit for accessory drain), we could then conclude with relative certainty a 350W RMS system will probably not benefit from a capacitor in an S2000. I'd say that covers most people, but certainly not all.

The tests were very well done and explained, but leave me with a couple questions:
1, How does a 4ohm resistor behave differently than a 4 ohm speaker? I suppose it pisses the wife/neighbors/dog off less..
2, How's it work in the car with the alternator as a power supply, both at idle and cruising RPM?
3, How much will the effects vary from manufacturer to manufacturer? While I believe it's possible a cap could help my Rockfords and other lower-end amps, I don't think they'd help at all with something way better like a Soundstream DaVinci or Tarantula.

A 1000W cap-less system like mine makes a good testbed. Anybody in SoCal got a cap at least 1.5-2F they can lend me to do some further testing with?

Half my original concern was the long term battery drainage issue (which we all agree a cap won't help with, right?), and after about a month with the sub, I can report no problems. The car has run and started like a champ, and has survived several 5-10 minute engine-off demonstrations.

Ears ring, mirrors shake, lights (but not the HIDs) dim, car alarms go off 50 feet away; got more bass than Helen Keller would know what to do with yet still I fuss...

 

I don't know what "fading" is. Can you explain?

That's exactly what I did in the test.

What do you mean by low end response? How much is a "significant" difference? I'm looking for something I can measure, not "the bass sounds better". Was it louder? By how much on a dB meter? Did the frequency response change? What was the F-3 before and after? (3 dB down points). Any audible change should be seen on the scope, unless we're talking about THD or something similarly difficult to measure without specialized equipment. But then power supply changes (adding a cap) shouldn't affect THD anyway.

I agree 100%. But that's not the question. The question is WHAT is the difference and is it significant enough to make an AUDIBLE improvement in the system? Blinking or not blinking lights does not automatically make my system sound better. Improving power supply performance might make a difference in amp performance, but that should be tested and proven, not assummed.

 

[QUOTE]Originally posted by Pinky
[B]Ok lets say this.

 

[QUOTE]Originally posted by jerrypeterson
[B]Remember in the previous thread I was trying to point out that the cap isn't for increasing headroom, its for maintaining it.

 

[QUOTE]Originally posted by jzr
[B]Wow, excellent job!

 

[QUOTE]Originally posted by modifry
[B]I think I agree with you.

How would a 4 ohm sub suck more power than a 4 ohm load resistor?