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The "Big 3" is a very easy mod to your car’s electrical system that will help it maintain higher voltages for more power hungry amplifiers. If you’ve ever measured your voltage drop when playing music with the volume to the max with your engine running, you’ll see that instead of reading 14.4v or 13.8 (depending on car), your voltmeter will read 13v, 12v, or even lower! You can easily tell if you’re experiencing these voltage drops by watching your headlights. If they dim while playing your system, you most definitely have voltage drop going on.  This voltage drop could potentially cause harm to your amp if it is significant enough.  I had a Treo SSX 1500.1 blow because I was letting my voltage drop to about 9-10v, which the amp didn’t like very much.

What causes this problem are the stock, small gauge wires used to connect various electrical components. The stock wire is usually 8 gauge, which is sufficient enough for roughly 50 amps. Large amplifiers can pull up and over 200-300amps, so now you see the problem.

When doing this mod, 3 runs of wire will need to be installed. They are:

1. Battery positive (+) to alternator - From the positive terminal on your battery to the alternator positive (+) post
2. Engine block to chassis ground - From engine block to chasis. This is to strengthen the ground.
3. Battery ground (-) to chassis ground - From the negative terminal on your battery to your car’s chassis.

Here’s a picture of the "big 3" when completed. The colored lines correspond to the colors of the description listed above.

I recommend using 1/0 gauge wire. You could use 4 gauge wire if that’s all you have laying around, but you might as well use 1/0 the first time so you won’t have to go back if you decide to upgrade your system later on down the road. The wire I used was Knu Konceptz 1/0 Kollosus Kable You will also need 1/0 ring terminals to terminate the ends of the wire.

Before you do anything, make sure to be safe. Disconnect the wire from the negative terminal of your battery before you begin. This makes an incomplete circuit and keeps you safe from sustaining electrical injuries.

First, measure a length of wire to go from your battery positive (+) terminal to your alternator.  Make sure to leave a little bit of slack, around 6 inches, so you’ll be able to position the cable freely.  Terminate the ends of the cable with ring terminals, then connect the wire from battery positive (+) terminal to your alternator.  There may be a plastic tab on the alternator post.  If there is, go ahead and break it off; it’s what I had to do.  If you don’t remove the plastic tab, you won’t be able to remove the nut off of the terminal post.  Here’s a closeup pic of the run of wire at the alternator.

Adding a fuse to go in between the battery positive (+) and the alternator is highly recommended, but not necessary.  There is a small chance that the wire will come lose and short out, but it’s a chance some people do not want to take.  On the contrary, I have had no problems in the 2 years I’ve had the big 3 installed while running an unfused wire.

The next step is to run a wire from your engine block to your car’s chassis.  This step may be difficult because you may have a hard time finding a place on the engine block to attach your wire.  Look for a non-essential bolt; do not use a bolt that holds fluids back.   Below is a close up pic of where I attached my run of wire to my engine block:

From there, you then need to attach the other end of the wire to your chassis ground location.  This ground can be anywhere on your car’s chassis/frame, but make sure that you have metal-to-metal contact with the terminal and your ground location. A good start is to follow your stock ground wire back to its grounding location.  If there is paint on the ground location you have chosen, you must sand it off until it is bare metal to ensure minimal electrical resistance.  Below is another closeup picture, this time it is showing the ground point I used for both the engine block, as well as the battery ground.

The location is a little rusty, but you can see how I sanded off the paint until it became bare metal.  The rust is because of time; I did this big 3 installation about 2 years ago.  To prevent rust, use a rust inhibitor product around the contact points.

Lastly, the final step is to run a wire from your battery’s ground (-) terminal to the ground location on the chassis.  Measure the wire and be sure to leave a little slack in case you need it.  Then terminate the ends with ring terminals and attach one end to the negative terminal and the other to your grounding location on your chassis (as seen above).

Once you have made the new, beefier battery ground, you can cut off, disconnect, do whatever you want to the stock ground wire because it is not needed anymore.  When you think you’re finished, go ahead and double check all of your connections making sure that they are snug and tight.

That’s it!  The "Big 3" is now finished.  You should notice a difference in voltage when playing your system at max volume.  Before I did this upgrade, my voltage was at about 10v under heavy load.  After doing the "Big 3" upgrade, my voltage under heavy load was stabilized at about 11v.  Quite a large difference for how much you spent on the wire and terminals.  That’s why the "Big 3" is considered the first electrical upgrade you should do to ensure consistent power to your amplifiers.

If anybody has any questions, leave a comment and I will leave a prompt answer.

In my experiences, many newbies think they need a capacitor installed along with their amplifier and subwoofers because of the reason that a capacitor will provide power when the amp needs it. Here’s the problem: The amp always needs power, and whatever “extra” power it needs will be sucked out of your capacitor in milliseconds. After you have discharged the capacitor due to heavy power draw, the capacitor will need to recharge.

How does it recharge? Well, the capacitor sits in between your battery and your amplifier. Once the capacitor is discharged, it will attempt to charge itself by drawing power from your battery. Then, when the amp needs power, the capacitor will supply current from the battery as well as any “extra” current it has saved up. Once its discharged, the vicious cycle continues.

Most common car audio capacitors are rated at 1 farad, while I’ve seen some reach as high as 5, 10, 20, and higher. No matter how high the rating, a capacitor will still hamper performance. This is because capacitors cannot supply the needed current for any extended duration of time. When your amplifier needs current, it will suck the capacitor dry in less than one second, leaving your capacitor to use your battery to charge up again. Once the capacitor is charged, that extra current can then be transferred onto the amp.

See where I’m going now? If a capacitor can only hold a charge for less than one second, while drawing substantial amounts of current from your battery in an attempt to charge back up while delaying power the amp, then what is the point? There is none. Capacitors are known in the car audio community as a marketing ploy to make people think they need something, when in reality, they really don’t. Take your money and invest it in a second battery. A capacitor these days runs between $50-$80. Add a few more dollars and you can get a second battery, which will supply your amplifier with much more power than a capacitor ever could, while not straining your electrical system.

In my opinion, the correct enclosure is vital in getting the most out of your system. This is because the enclosure determines how your sub will react with the given airspace, tuning, and power. For example, a sub in a sealed enclosure will sound very different than one in a ported enclosure. Ported boxes are easy to identify because of the port opening. A combination of port area (length x height) and port length work together to create the tuning frequency. The tuning frequency is denoted by hertz (hz), usually in the 20-70hz range when speaking of sub frequencies. Sub frequencies are also why subwoofers are called “subwoofers” and not simply “woofers” which refer to midrange frequencies. A combination of size and tuning determines the output of a system more than the power or subwoofer itself. You could have a high end subwoofer like a DD 9515, but in the incorrect box, it could be outdone by a lower end sub in an optimized box.

The key to making the best box possible is simple: test, test, test. There is no one best design because every car is different and will react differently with different boxes. Through lots of testing, I found that my car likes large boxes and a 40hz tuning. I’ve gone up against many people with more than twice the cone area (double the amount of subs) and have come out on top, even though I’ve got half the cone area in a very restricted sedan rather than the open cabin of an SUV. During these competitions, your score is measured in decibels at your highest frequency. Therefore, it is extremely important to tune your box to reflect your highest outputting frequency. Right now, my box is tuned at 40hz and it also happens to hit its peak output at 40hz. That may or may not be the case for anybody else because as I said before, every car is different. Also, don’t forget to take your subwoofer into consideration. Most of the time, you will usually peak a few hz above tuning. E.g. a tuning of 32hz may result in a peak of 40hz, depending on the car of course. In essence, tuning at a certain frequency allows you to control your output and determine what note you want to play the loudest, which is important when taking your car into consideration. Hatchbacks generally hit their highest score at higher frequencies (50-70hz) and SUVs generally hit their highest score at a lower note (40-50hz), while my sedan likes lower notes in the 40hz range the best.

Once you figure out what note your car likes, you can then start optimizing your box by making some small changes. Generally, slightly larger boxes with lower tunings perform best for cars that like lower notes. Slightly smaller boxes with higher tunings tend to complement cars that like higher tunings. For music and daily driving, tunings between 30-40hz are generally accepted as a fair tradeoff between sound quality and loudness.

Some helpful links:
http://www.bcae1.com/
A great beginner’s site and excellent for reference of various concepts.

http://www.caraudio.com/forum/showthread.php?t=61853
A thread explaining tons of car audio terms

For more information, the CarAudio.com forums have been very helpful. Just search for whatever you’re looking for in the forums or post a question.
http://www.caraudio.com/forum/index.php

Car audio, one of my favorite hobbies. Some people go for sound quality and some go for loudness, or SPL (sound pressure level). I started out about two years ago with my first set of 12″ subs from Infinity, then moved up to a pair of 12″ Alpine Type-Rs. The amplifier I used was a Better Audio 1600M1 rated at 1600wrms (watts rms) @ 1ohm. The Type-Rs held up my SPL addiction pretty well until I started to compete in MECA, a somewhat local car audio competition league. It was there I learned that my Type-Rs had nothing on the big boy companies: Digital Designs , Resonant Engineering, American Bass, and TC Sounds just to name a few. These guys were pumping out scores in the 150 dB (decibel) range while I measured in at a measly 145.1 in the kick. I wanted something that was louder, lower, and capable of handling power. Not only that, but I didn’t want to spend over $400 in new subs.

The solution was Audioque. Not wanting to go into too much detail, I eventually ended up with a single 15″ Audioque HD3. Now the question is power. I started with a Treo SSX1500.1, but it blew up less than a month later which was because I was running the amp at .75ohms and didn’t have a good electrical system in place. Low voltage (10v!) + low loads (.75ohms) = fried amp. I then went with a modded MA HK4000D which puts around 3200-3500 watts @ 1ohm running on 12 volts. A higher voltage, say 14v, 16, or even 18v would make the amp put out even more power, but my weak Honda alternator and 2 batteries cannot maintain 14v for very long. Then comes the enclosure, which was a 4.5 ft3 tuned at 40hz with 4 4″ “aeroports”

The most recent score I have is 147.2 dB @ 40hz taken at the headrest during the Carl Casper Autoshow last year. During the earlier year prior, I was able to finish 2nd and 3rd in two different classes at the MECA world finals. I ended up finishing 1st and 3rd in two different classes at Carl Casper. Lastly, here’s a video of what I’m working with.