Medical school students study hard at night over books of human anatomy. Believe it or not, installers of car audio systems must be concerned with anatomy, too. For a sound system to work well, its heart and veins must be sound so that its blood can reach out properly to all of its extremities.

The heart of a sound system is the battery, and it is the cables which carry the life force. For the system to be in tiptop shape and good working order, like a human body, all facets of the anatomy must be working properly. That means that the electrical system of the car cannot have any glitches.

That is why good installers check out the electrical components of the car before installation and go on to continuously check that, is working well. But what do you check for? And what do you do if you find something improper? We have enlisted the help of Isaac Goren, owner of Sounds Good Stereo in Woodland Hills, California, to explain all of this. Goren has been involved in car audio for more than 20 years. He is also a pioneer in the creation of sound-off events, which are now common in all regions of the country and the world.

A SHORT PRIMER

First, a short explanation about a car's electronics. Goren pointed out that an audio system in a vehicle runs on 12 volts. An audio system in a home works on 120 volts. "When dealing with amplifiers for vehicles, 100 watts may not be sufficient," explained Goren. "But in a house, a 100-watt amplifier can blow the family out of the house." According to Goren, the difference has to do with the car and efficiency.

A car's electrical system includes a battery which supplies 12.8 volts at rest. When the electronics are turned on, the battery voltage drops down to 12 volts. The main reason for the battery is to start the vehicle. Once the vehicle has been started, the alternator takes control, said Goren. It spins and while it spins it's creating electricity or energy and supplying that electricity or energy to the entire vehicle.

"When someone installs an audio system, they take power for the amplifier(s) from the battery," explained Goren. "We all assume, therefore, that it is the battery that is giving the energy. Actually, that is not totally true. In fact, the alternator is supplying the energy through the battery."

An alternator consists of diodes that can burn out and cause the electrical system not to charge properly. In fact, if the alternator is not right, it can discharge the battery. The alternator is commanded by a regulator. The regulator can be built inside the alternator, it can be external, or it can be built into the computer of the vehicle like many of the new foreign cars.

The regulator tells the alternator how much, current it needs, to supply according to the demand. "You can have the headlights and air conditioner on and the battery may be low." explained Goren. "The regulator senses that and tells the alternator to make more power. This means that the alternator never creates more current than the car needs, which could burn electrical parts of the car."

While the car is running the alternator generates current it 13.8 to 14.3 volts. That current is going directly to the battery and the amplifier is tied directly to the battery because it is the component that draws the most amount of current.

So, before you install a sound system into your vehicle, you need to be certain that the electrical system alternator and battery is working properly. Goren suggested that you start the car and then use a volt meter to monitor the voltage rate of the battery. He said that it should be near 13.8 volts with the car at idle. "That tells you that the alternator is charging properly," he said. When you get a friend to rev the engine, the volt meter should show 14.1 or 14.2 volts, depending on the vehicle.

DECISIONS, DECISIONS

If you intend to use a large amplifier in your sound system, or even multiple amplifiers, you may want to consider upgrading the alternator of your car. According to Goren, you can take your present alternator and have it re-wound so that it will create a little more current or you can buy an aftermarket alternator that generates more current.

If you do upgrade the alternator, you should also upgrade the charge line which goes from the alternator to the battery. According to Goren, usually you will find 8-gauge charge wire in the car. Goren recommended that you upgrade it to 4-gauge. "Electricity flows like water," explained Goren. "It tends to take the easiest route. So the bigger the power-wire, the easier it is for the current to flow."

Next, you will want to consider the battery, If you intend to upgrade the battery, Goren counseled that you buy a well known brand such as Interstate, Optima or Megatron. He noted that battery specs can be confusing, but Goren suggested that you choose an Interstate battery with a cold crank rating above or an Optima battery with a crank rating of 800.

You may also want to consider including a second battery if your sound system will require a lot of current or you are concerned about your accessories. A second battery, if added properly, will provide more current for the sound system. "The second battery can work the sound system and other accessories while the original battery can power the car's electronics and starter," Goren said "It means that you will always be able to start your vehicle regardless of what happens with the accessories."

He added that the second battery should be a deep-cycle battery. These batteries are usually used on boats. A conventional battery will not re-charge to its full capacity after it has been drained dead five times, noted Goren. A deep-cycle battery, on the other hand, will re-charge to its full capacity, he said.

Use a solenoid or isolator with the second battery. This ensures that when you use your stereo when the car is not running, you will drain the second battery without effecting the main car battery. The charge line should run from the alternator to the main battery on to the solenoid and to the second battery in the rear of the vehicle. Four-gauge cable can be used as the line.

If you add a second battery, you definitely need to upgrade or replace the factory alternator or add another alternator. The factory alternator is designed to charge one battery. If you add more demand, the alternator will have a hard time charging the battery to keep up with the demand.

Moreover, if your system is using more than one amplifier, it would be include a distribution block to ensure that power is properly distributed to all of the amps. Many distribution blocks include a fuse distribution block to make it easier to include protection for the amps. A ground distribution block is also advisable.

Finally, you may want to include a stiffening capacitor to ensure that the power flow to the amplifier remains constant. A capacitor is a device that stores electricity and quickly releases it on demand. It especially helps the bass of the system when the amplifier needs the most power. A 1-farad capacitor should be used with every 1,000 watts of power supplied by an amp or amps. A 1/2-farad capacitor is good with amps that generate 500 watts of power. So, if your system is generating 500 watts and below, use a 1/2-farad capacitor. If it is generating more than 500 watts to 1,000 watts use a 1-farad capacitor.

When you consider the wattage of the amplifier when deciding what size and how many capacitors to use, consider the wattage that the amplifier is really generating. Remember, when you reduce the ohms load on the amp, you are increasing the power of the amp beyond the rating that appears on the amp's shroud or the box that it came in. "if you buy a Rockford 400x4 amplifier and its specs say that it is rated at 50 watts x 4, remember that at 13.8 volts and installed in a 2 ohms load, the amp actually generates, say, 160 x 4," cautioned Goren. "Use the 160 x 4 as the number when deciding on the amount and size of the caps."

PROTECTION AND SAFETY

When you are fooling around with electricity, you must be certain that your electrical components and the car's electronics in general are protected from possible damage caused by shorts. It is not difficult to do this, but it means that you must concentrate on the details.

Make sure that the power cable going from the battery to the amplifier is fused or that there is a circuit breaker within 18 inches of the main battery. This protects the power cable going from the battery to the amplifier(s). Since the power cable is heavy gauge, you also need to put a fuse at the amplifier(s) if the amplifier(s) do not have a built-in fuse. Keep in mind, however, size fuse so that the power can flow with the least resistance.

According to Goren, battery connects are also critical. Some shops sell gold terminals or posts. The gold is not just for looks, it offers less resistance for the electricity and more resistance to corrosion. That's not to say that there won't be any corrosion build-up on gold terminals. In fact, there will be and you need to clean the corrosion off from time to time. But at least, there will be less of it. There are sprays available to assist you in the cleaning process.

You should also be aware that corrosion can grow from the battery terminal into the power wire. If you find a lot of corrosion, replace the battery and check to see how much has grown on the wire and replace the wire if the corrosion has gotten into it. Remember, corrosion will continue to grow if left alone.

Finally, you need to consider the bolts you are using to make your connections. The bolts used on the positive side connections passes on current, too. If a bolt is exposed, it may become responcible for a major short. Cover the bolts with a rubber boot or silicone.

DOES YOUR SYSTEM NEED AN UPGRADE

Many of you who are reading this article may already have a massive sound system present in your car. You are probably thinking that much of what appears here does not or cannot pertain to you. But you may want to consider some or all of the upgrades outlined here for your system. How would you know if you need an upgrade? If you run the bass loud and the car's dome light or headlights dim with the music, then your system is not getting all of the current it needs and the car is lacking the power it needs to run. The amplifier of your sound system is probably not getting enough current. So it may clip, get hot, and simply not deliver a much power as it can. If you follow the procedure described here, you sound a whole lot better and your lights won't dim. The system will get more current and deliver 3 to 6 dB more sound. Moreover, the system will sound cleaner.