what are you running in your system?

 

I'm not going to give you a bunch of technical mumbo jumbo, but I will tell you this. My friend is a professional installer at the top local stereo shop. On my last car, because I was worried about light dimming, he told me that when running two amps a cap is a good idea. So I installed one and ran it for 3+ years. I will be adding this cap to the new stereo set up in my G.

 

Perhaps the context in which we are discussing this is wrong. On a technical level, if the sensitivity of the speakers are the same, then the wattage required to produce the same dB at any frequency will be the same. But this realistically only occurs in controlled environments where testing conditions are equal. A car imposes several issues. Particularly with subs. They are generally mounted in a trunk and isolated somewhat. The wavelengths of sound a typical sub creates is also rather large. They tend to spread in several directions. High frequency speakers tend to be aimed so the sound waves are actually maximized to a particular area or direction. Given that, the actual wattage needed for the listener to hear the same dB from each speaker in a typical car is less for speakers dedicated to high frequencies vs those dedicated to low ones. I know both my hatchbacks allowed much more bass into the passenger compartment than my last coupe did.

As far as the snare drum thing, I think he may have been referring to the type of sound(not frequency, but duration and impact). Bass frequencies with the same technical dB output from a speaker with the same sensitivity should require the same wattage(power) requirement if the sound being played has a similar duration, and impact. So a cap would be equally as effective. I'd like to hear the context in which he said this. He is a great mind when it comes to sound, but I have a feeling it may be misinterpreted here. Is this in his book btw?

Capacitors are necessary for any amp to some degree. Keeping in mind amps have them built in. So are they(outboard caps) really necessary? It depends. Again, I find them to be a poor solution for a lack of reserve capacity from an alternator. In actuality, outboard caps just feed the amp's built-in caps. Any system should be built within the alternator's reserve capacity, or the alternator upgraded to have enough reserve capacity. For a cap to discharge the load and current draw must be high enough and long enough that the alternator can not keep up. And so long as there is voltage from the better or alternator, the cap will never discharge completely. It will stay at the same voltage as the rest of the electrical system(except if the circuit is open). So if the entire electrical system sees a voltage drop as the cap releases it's stored power in it's attempt to keep voltage higher, the cap will eventually see the same voltage drop. So what does a cap really do? It lessens the voltage drop to a degree when there is an immediate demand that the car's electrical system can not handle.

 

Upgrading a battery is not going to do a lot of good. While the motor is running the battery generally does very little. If you exceed the alternator's reserve capacity, then it will start to pull power from the battery. The voltage will start to drop. A battery with a larger reserve capacity may take longer to do this, which might help if you only turn up the music for short durations, but longer trips with the music pumping the whole time may pose a problem if the system draws more than the alternator puts out.

I prefer Optimas(deep cycle only) for their ability to withstand many many full discharges and their virtually non-existant maintenance schedules. My last Blue top lasted me 5 years and was still strong. I really shoulda kept it.

As far as swapping wiring, I'd definitely do it if I were upgrading the alternator. If not, then you may want to check to see if the wire is putting an measurable amount of resistance as it may free up a little bit of reserve capacity from the alternator. A larger guage may not even be necessary, but a high strand count wire will move more electrons as there is more total surface area(electricity travels along the surface of metal, at least the majority does). To what extent this has an effect, I don't know, but bigger cables with a higher strand count certainly can't hurt.

 

al503 I'm running the JL 300/4 and 500/1. So I guess I should get a new alternator then??? I'm Super Confused now What if I drop a few "No Dose" tablets in my tank will it stop dimming?? or how about Red Bull.? LOL j/p.... but really I'm confused.All I wan't Is my car not to dim when I pump my system up (and I do this Often) and I don't wan't to cause damage to my car by listening to it loud it sounds like I can damage my car if I keep sucking the power out of it.


2004 Skyline 350GT 5AT DG/G Clears,Bats, Now wit Bumps in da back! [img]/w3timages/icons/shocked.gif[/img]

 

Also If I do an alternator upgrade what will that cost more or less? and should I look for any particular brand and spec?

2004 Skyline 350GT 5AT DG/G Clears,Bats, Now wit Bumps in da back! [img]/w3timages/icons/shocked.gif[/img]

 

CKwik,
The context was this:
I explained to him what I was running (450/4 and 500/1), the power output of my alt (measured at 126 amps at 2200 rpm), and that I had dimming and engine stuttering problems when the system was cranked. I asked him whether a capacitor would help with the dimming and stuttering and he responded that it would not have an appreciable affect. He then explained to me when a cap is actually beneficial and that's when he gave me the snare drum example.

Good info on the alt/battery issue. I would also suggest adding another battery instead of just swapping your stock one out. However, what Ckwik said about running your system full blast constantly is very true. If the power consumption of your system is more than the alt can put out and you don't have enough system down time (either off or at reduced levels) for the alt to re-charge your battery, then you'll either have to recharge the extra battery externally or upgrade the alt.<P ID="edit"><FONT class="small"><EM>Edited by al503 on 09/29/04 08:21 AM.</EM></FONT></P>

 

istick2u,
As with any issue, there are always differences of opinion and that's what keeps thing interesting imo.

My salesperson at cartoys (where I bought the amps from) told me that a cap is not going to help with dimming. This is from a guy who makes his living selling those products. I would think that there is a nice spiff/commission on an add-on sale such as a cap.

Based on this and the advice from Manville, I came to the conclusion that caps won't help with the dimming. It's an educated adoption of a particular position in the same vein as how you've come to your position on this issue.

Based on the above, I respectfully propose we agree to disagree as both positions seem to have arguable merit.

 

al503,

I totaly agree with you. I sell optimas and caps. I make more money on caps than I do optimas. But I feel I would be doing and injustice to my customer by selling them a cap to solve the dimming problem.

On a side note. Caps that are installed more than a foot of wire away from the amp become ineffective anyway. I can't tell you how many times I see cars come in with the cap installed with more than two feet of wire between the cap and the amp.

istick2u,

It is clear you know your stuff too and have good merits to your argument. I am only going on my own experience and knowledge of car audio. I repsect your argument because you see the value of a good deep cycle battery too.

IMO this is one of those good forum posts that bring very knowledgeable members together to debate a issue that is very helpful to the whole G community. Now everyone can make thier own educated choices on what they want to do.

Rudy

Do you hear me?

 

a new, more powerful alternator is the best solution. However, it's also one of the most expensive. I also don't know if anyone is manufacturing one for the G yet.

Another option is to have your stock alternator re-wound to make more power. The only reservation here is that you'll have some down time when you send in the alt and they usually put out less juice at lower rpms than they did before to get the extra power up top. If you do a lot of highway driving (keeping the revs up instead of idleing in stop and go), this may be a good solution.

The last option I can think of is to get another deep cycle battery. Hopefully you'll have enough down time so that the stock alt can keep it charged. If not, an external charger would be necessary, which would be a pain in the butt.

 

here, here, remani. Put the information out and let everyone make their own informed decision that's right for their situation.

 

The electrical system in most cars is designed to supply power to all the factory-installed components and accessories. If you add power-hungry amplifiers, the car's electrical system can not keep up with the current demands. The car's components and your audio system are in a constant fight for the low power resources.

<u>Capacitors</u>

The first thing to do is to add a stiffening capacitor. A capacitor acts as a secondary battery that reacts very quickly to sudden current demands (i.e. music transients). A rule of thumb is to have 1 farad of capacitance for every 1000 watts of power. The sound system will sound a bit smoother and hopefully the light dimming problem will be either fixed or reduced. Your lights don't necessarily have to be dimming for you to have to add a capacitor. Stiffening capacitors always help a sound system.

Capacitors should be installed as close to the amplifiers as possible, with the positive lead going right into the positive lead of the amp and the ground to a metal part of the car (not to the ground terminal of the amp).

<U>High Output Alternators</u>

Another upgrade is a high output alternator and maybe adding a secondary battery (for car off listening) to keep up with higher system's demands. This should be done by someone who has a fairly good understanding of a car's electrical system, since computers are designed to control the factory components.

<U>Additional Batteries</u>

Always keep in mind that when a car is running the batteries become loads that take power away from your amps. The advantage of secondary batteries is that when the car is off, you can listen to your stereo for longer periods of time.

Adding more batteries will not make your stereo perform any better when the car is running. In fact, a second battery will steal power from the electrical system when the car is running. A battery isolator should be used to avoid batteries draining each other.

Replacing factory batteries with high performance batteries will also improve power output. Companies such as Optima make batteries that take less power to charge and have a higher output, placing lower demands on an electrical system.

If you have a powerful system and not some cheap amps you should consider one of the options listed above. A Cap may not be the best, but will not hurt your system and would be the least expensive. Yellow tops are a great alternative also and thanks to sites like eBay all these options are affordable.
__________________________________________________ __________________________________________________ ________
<a href="http://www.mmxpress.com/technical/capacitors.htm" target="_blank">Click Here For Cap Article</a>

PS I do not find CARTOYS to be a highly regarded business. I contacted them a couple of times just to ask some questions and caught them in a lie. Also CARTOYS does not offer a lot of the higher end equipment like Phoenix Gold, or MB Quart, or Kicker, etc.
PSS I did not run a cap in the first car that I installed my stereo in and headlight dimming was a very bad problem and my alternator went kaputzki. When the very powerful comp system was put in my last car I added a cap, my lights did not dim and I never had a problem. You don't have to go with a cap, but you should do something about the power drains if, and it looks as though you did not go with, a cheap system.<P ID="edit"><FONT class="small"><EM>Edited by istick2u on 09/29/04 10:35 AM.</EM></FONT></P>

 

1. I don't follow. Am I a di(k because I disagreed with you?

2. I wasn't the person(s) asking for advice. I was giving mine based on my experience. You were doing the same thing. Just because we have different opinions doesn't mean either of us is wrong.

3. Just like car dealerships or any other chain stores, there are good ones and there are bad ones.

At the risk of another unwarranted (IMO of course) attack, may I ask what I said that rubbed you the wrong way?

 

WOW, where did that come from?

Do you hear me?

 

In terms of the link to the article itself, I always look at the source. Does the source have a vested interest in the contents? In this situation, we have an article on a site that is selling car audio equipment. I'm not saying that they are flat out lieing but it does raise a question in my book.

I think a better opinion can be found in a forum, like this one, where car audio enthusiasts share their experiences. If you go on sites such as sounddomain.com and search for 'caps' the vast majority of the members there (just like you and I on this forum) will tell you to skip the cap. Some will have a much stronger opinion and not use the word skip.

I've purchased a lot of wiring accessories from darvex.com for my installs and my bud's installs. I talked to Trail McFarland the owner there about the cap issue. Even though he sells them, he said that they will not help with the dimming issue. He told me to get an additional optima (even though he doesn't sell them) instead.

Quote:
"A Cap may not be the best, but will not hurt your system and would be the least expensive."

Couple things wrong with this. In terms of the caps v. additional batteries information in your post, it seems to contradict itself if you look at it closely. A capacitor is nothing more than a small battery (if you define a battery as a device that can be charged with energy and discharge it when needed) that can discharge faster than a normal car battery. One of the cons mentioned for additional batteries is very true of caps but not mentioned for the caps. Once it discharges, the cap will "steal power from the electrical system when the car is running" just like a battery will.

In addition, a 'good' cap runs up to $200 for 1 farad. You can get the top of the line optima yellow top at a store for ~$150 an even less on ebay.

Quote:
"Adding more batteries will not make your stereo perform any better when the car is running."

Again, if a cap is essentially the same device as a battery that will charge, discharge, and then recharge (thereby placing another source of strain on the electrical system, just like an additional battery would) it looks like they're trying to have it both ways.

I agree that having an additional battery will show it's advantages most clearly when the car is off. However, the in the same situation a cap would discharge, the battery(ies) will also. If the system is sucking more power than the alt can handle, the amps will look to the next highest source of power which will be the cap, if you have one, and then to the battery(ies) at 12 volts. I would argue that having another battery to draw upon and thus keep the system closer to 12 volts, the better.

As I stated in my earlier post that may have been misconstrued, there are arguments on both sides that have merit. I think that this thread will help others make a decision that is right for them as you and I have made a decision that is right for us.