I have a pair of dual 4 ohm voice coil subs. I can either wire them as a 1 ohm load or a 4 ohm load across all four voice coils. What are the benefits of running 1 ohm load instead of 4 ohm load and vice versa. I wired them up as a 1 ohm load, and I do notice that the bass is louder, but my dashboard lights also dim much when the amp is under heavy load.

 

As you found out the benefits are more power but the truck needs to be able to provide more power to the amp. What amp? What size is your power wires?

 

It's a Soundstream PCX2000D with two Kicker L7's. The power wire from the battery to the trunk of the car is 0 gauge with 4 gauge from the distribution block to the amp. In my truck, I am running an Alpine PDX-1000.1 with a pair of Rockford Fosgate P3SD410's, but I am running a 4 ohm load, since the Alpine amp supposedly runs at 1000 watts at 2 ohms or 4 ohms.

 

Benefits of running 1ohm:
-More power = louder

Benefits of running 4ohm:
-Less stress on the electrical system
-longer life from your amp because it wont be producing as much heat
-better sound quality due to more resistance, which provides more control from the amp

Your lights dim due to voltage drops when the amplifier demands high current at high volume. You need a high output alternator and better electrical ground to fix this. Although many might recommend it, capacitor is NOT the right fix.

 

Reason being? Amp's have many small capacitors inside of them, I see no harm in using a cap vs spending hundreds on a new battery and alt.

 

ohhhhh boy.

You might want to do some research or homework which will explain how a cap is not only a waste of money but in fact will put more stress on your car/truck.

Anyways to the OP, just make sure your amp is 1ohm "stable".

 

Well then I don't want to derail this thread since that is such a touchy subject, but at least you can still start a truck off of cap when you have a dead battery, LOL!

 

Thanks guys. The Soundstream amp in my son's GTI is stable to one ohm, and that was how he demanded that I wire the speakers to get the full 2000 watts RMS. The Alpine amp in my truck is only stable to 2 ohms, but Alpine says that the amp runs the same 1000 watts RMS at either 2 ohms or 4 ohms. I made a mistake and bought the P3SD410's instead of the P3SD210's, so my only options was 4 ohms. As far as the lights dimming go, it's just the dashboard lights. His GTI has HID's, so the headlights don't dim at all. He is talking about installing a second battery in the trunk. Since we already have 0 gauge running to the trunk, it should not be any trouble.

 

Oh there is no harm in using a cap, by all means it doesn't do anything negative (and sorry if it came off like that). However, a capacitor is more of a "bandaid" then an actual solution to the problem. It will give a short-term boost in voltage, but after a certain period of high current draw from the amplifiers the capacitor will drain and won't help anymore. If you want that high powered of a system, you really should properly upgrade the electrical system, thats all.

 

i would first try to upgrade your ground wires. if that does not work a alt upgrade is needed.


like the others have said, i cap wont help. its just a battery. If your electrical system does not even have enough juice to keep the lights from dimming what makes you think the system will have enough juice to charge the cap as well?

 

A cap isn't a battery. It behaves quite differently and more importantly has a minuscule storage capacity. You don't necessarily need to upgrade the alternator. Many times the addition of a second battery will have the desired effect.

Adding an upgraded alternator alone won't help with dimming lights. The inductance of the alt keeps it from responding immediately to transient current demands. Here's the analogy that I use that usually helps people grasp the concept. Think of your truck electrical system like an air compressor and air tools. There are two vital components to an air compressor and each has a specific purpose in the system. One is the air pump and the other is the air tank. In the electrical system these are the alternator and the battery (or batteries) respectively. Likewise you have two types of air tools, high instantaneous demand like an air nailer and long term demand like a sprayer. These would correspond to items like amps and lights respectively. Instantaneous demand items rely on the pressure tank to provide the pressure needed, the pump merely keeps the tank topped off. Likewise your amps draw some of the current reserve off the battery during loud transients and the alternator tops the battery back off. Only when you have long term high draw items does the air pump become a vital part of keeping the pressure steady. Same with the alternator. The average current demand over time is what you care about when looking at the alt. Peaks are leveld out by the battery.

A cap *could* do the same thing if it were big enough. Problem is that you would need lots of really big caps wired in to equal even a small battery. Assuming a lossless transfer of current (which a cap is not nearly capable of with the bigger caps usually having a higher internal resistance and increased loss) a cap is capable of storing a whole usable 0.5 amp-seconds of energy per Farad. Installing one won't hurt anything, but it won't do anything either, besides taking money out of your wallet.

 

Another analogy:

A cap is like running NOS through your motor (or electrical system) whereas upgraded battery and alternator is more like rebuilding the motor to be bigger and stronger, then adding a supercharger on top of it. The cap may give a short burst of power like NOS, but in the long run, it isn't gonna help anything. Whereas with the upgraded alt. and battery, you have a constant supply of energy. A quick burst of power may be beneficial when racing the 1/4 mile, but not necessarily when jamming your subs for extended periods of time.

To the original post, another benefit of running 4 ohm over 1 ohm is sound quality. While it may not be easy to tell the difference in your subwoofers, when you get into your mids and highs, it makes a big difference. Most home audio and even some super high end car audio speakers are 8 ohm as opposed to the typical 4 ohm. If that amp really pushes the 1000 watts like alpine says at 4 ohm, then I would leave it at 4 ohm and not worry about the electrical upgrades other than upgrading your grounds. Do a yahoo search on "The Big 3" and you'll see what needs upgraded in your electrical system.

 

Actually a cap would be more like putting a fart can muffler on your car. Your friends who don't know anything might think that it's cool but it adds nothing constructive to the situation.

 

Why dont we stop dissing caps? Everyone who actually cares about their build knows they are garbage, and all the ricers think they are hot stuff. Get a second battery if need be, but never get a cap. Also, unless you are burping the subs constantly, I dont think you will need a new alternator, although I am sure it would relieve some stress off alt if you got a better one, but no need for a 300Amp alt when only doing like 1kW.

I have been holding off, but I need a new alternator for my sound system when I install it. I have this choice right now - Either have 3 seats in the back, or have 1 amplifier thats the size of 3 seats...decisions decisions...

P.S. If I was in your shoes, I would run to the local auto store or where ever you can get a small sealed battery and buy it. You dont need some batcap xtreme or anything, just a small regular car battery will work fine. Put it in with your system, because everytime that your lights are dimming, it means you electrical system is working hard. I would personally wire the second battery up with a solenoid that lets it charge when the ignition is on, but it will not drain the other battery when you are not in the truck. This would make the subs on a somewhat separate electrical system, so they don't strain your vehicle.

Sorry if that was too much text

 

I'm kind of in the same boat as you. I have 2 Stereo Integrity dual voice coil subs that will be ran by a JL 1000/1 this amp puts out the smae amount of power whether 4 ohms or 1 ohm. The rule of thumb with subs is to avoid as much as possible running them in series. The only way to get two dual 4 ohm subs into one 4 ohm load is to run each subs voice coil in series, and then parallel the two subs together..getting a 4 ohm load.

http://mobile.jlaudio.com/support_pages.php?page_id=161

Even though they say to avoid connecting two subs in series, but its ok to run the two voice coils in series, I think i'm just going to play it safe and run them in parallel since my amp is more then capable down to 1 ohm