Car Audio Amp Installation

Installing car audio amplifiers is one of the trickier things a newbie car audio installer can attempt. Car amp installation requires that all sorts of panels be removed and that various wires be run all over the car. Installing car audio amplifiers is a step by step process which I have outlined here. Please do not attempt a car amp installation if you are not comfortable with the process. Leave it to a professional. Now here are the steps on how to install a car amp. There is also a wiring diagram below. NOTE: These directions assume you have already physically mounted your amplifier to a solid, non-conductive surface.

Determine what side of the vehicle the battery is on. Disconnect the negative battery terminal. If you have a radio with a security feature (such as a Delco-Loc system) make sure you know the reactivation code before disconnecting the negative battery terminal.
Find a spot to run the power wire through the firewall. Try to find an empty rubber grommet that hides an unused factory hole. You can just put a hole in this grommet and run your wire through.
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If there is no factory hole you will need to make one. Get out the power drill and steel drill bits. Before drilling make sure you know where the bit will end up once it's through the firewall. I usually make a small pilot hole and then increase the bit size until the hole is big enough for my wire. If you have a stepped bit that would be great to use (see photo). I recommend them highly.
Protect the drilled hole edges from rust with paint or a similar material.
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Install a rubber grommet (see photo) into the hole to protect the wire from chaffing (VERY IMPORTANT!). Caulk the gap between the rubber grommet and the power wire if necessary to prevent water from running down the wire.
Run the wire from the interior of the vehicle, through the hole and to the battery, being very careful to avoid pinch points and moving parts in the engine bay.
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Install an in-line fuse holder (see photo) for the power wire as close as possible to the battery terminal connection (the IASCA rule is within 18"). VERY, VERY IMPORTANT!!!!! This fuse protects your vehicle from burning up in case of the power wiring shorting out. The wire between the fuse and the battery terminal will be unprotected, which is why you want this section to be as short as possible. The fuse size depends on the current the power wire will carry. Consult the owner's manual of your amplifier(s) to find out the maximum current draw of your system. You can also contact the manufacturer and ask them for that information. For multiple amplifiers you will need to add up the maximum current draw of each amplifier. Once you know the maximum current draw you'll know what size fuse to use. For example, if your maximum current draw is 50 amps then you'll need a 50 amp fuse. Do not insert the fuse until all other connections are made! Connect the power wire to the battery using appropriate connectors.
Pull back the carpet in the area you intend to run the power wire. You will need to remove the rocker panel and kick panel covers to do this.
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Snake the power wire to its final termination point (where your amp will be mounted). Be careful to avoid any pinch points such as seat tracks/door jambs, etc. Depending on your application, you can connect the power wire to the amplifier (using appropriate connectors such as ring terminals, see photo) or connect it to a power distribution block.
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of Parts Express

After you have your power wire run the way you want it, go back and use plastic wire ties to secure the wire in place. You may want to cover the wire in the engine compartment with wire loom also (prior to using wire ties).
Now run the RCA cables and remote turn-on lead (typically a blue lead but you will need to check your head unit's manual) from the back of your head unit to your amplifier's mounting location. You will need to follow a process similar to that of the power wire (steps 8 and 9). However, run your RCA cables on the opposite side of vehicle. You do not want to run power wires and signal cables on the same side of the vehicle. This could induce noise into your system. Connect the remote turn-on wire to your amplifier using an appropriate connector (such as a ring terminal). NOTE: The remote turn-on wire is what sends the signal to your amplifier to turn on. It is a very important wire and your amplifier will not work without it.

If you are using a factory head unit you won't have a remote turn-on wire. The cheap and easy way around this is to run the amp's remote terminal off of a switched accessory wire. This is the wire that your radio uses. It is only powered when the key is in the accessory or run position of the ignition switch. When you shut the car off the wire loses power and the radio and amplifier will both turn off. Your amp will be on when your car is on and off when you car is off.
There are also units that will sense the voltage on the factory speaker wires and then send a +12 volt signal to the remote wire. These units run about $35 and are an option for those who do not want their equipment on full time.
Now run your speaker wires between your amplifier and your speakers.
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Connect the speaker wires to your amplifier using appropriate connectors (such as ring terminals) and to your speakers using the appropriate connectors (such as female spade terminals, see photo).
Now you will need to connect the negative terminal of your amplifier to the chassis ground of your vehicle. Any metal point on the vehicle should work since they all lead back to the negative terminal of the battery. However, you should avoid factory ground points as these tend to be noisy. This negative power wire should be short and of the same diameter as the positive power wire leading to the battery. When connecting the negative power wire to ground, you may need to scrape some paint from the grounding surface. This will ensure better contact between the negative power wire terminal and the vehicle ground. After you have the negative terminal connected to ground, cover the connection with paint, caulk or a similar protective material to prevent rust. CAUTION: If you must drill a hole in the vehicle to connect the chassis ground, make sure you know what you're drilling in to. This is especially important when you are in the area of your vehicle's gas tank. A wrong move here could puncture the tank, cause a spark and set your vehicle on fire with you in it! If you are unsure then consult a professional.
After all connections are in place and all wires are secured, you may insert the main power wire fuse.
Reconnect the negative battery terminal.

How to Install a Car Amp Wiring Diagram

Now it's time to set the levels of your amplifier and other electronic components (crossovers, equalizers, etc.).

Level Setting for Beginners

Level or gain setting, done by ear, is more art than science. It can be done using an oscilloscope but since few people have one of those laying around we'll cover doing it by ear. Basically you want to start with the first component in the chain (head unit) and work your way to the last component (amplifier).

Start by turning all of the input level adjustment knobs (gain controls) on your components fully counter-clockwise (to their minimum setting). Set the tone controls (bass, treble, loudness) on your head unit to no boost (bass and treble level = 0 and loudness is off). Make sure your fader and balance controls are set to the middle position. If you have more than one RCA pair you will want to set each gain adjustment separately.
Next set all of your equalizers settings (if you have an equalizer) to the center (detent) position so they produce no boost or cut. What we want is as pure of a signal as possible.
Put in some good quality source material, preferably a CD with strong output and a clean recording. Hard rock would be a bad choice here. Try something cleaner, maybe acoustic, that you're familiar with.
Turn the deck's volume up slowly until you begin to hear distortion. When you hear it, stop and back off slightly until you no longer hear it. If you don't hear distortion, even when the volume is all of the way up then you have a quality head unit. That's what we're looking for.
Now with your head unit at maximum undistorted volume move on to the next component. Adjust its input gain until you begin to hear distortion. Back off slightly.
Continue this process until you have all of the components in the chain at their maximum undistorted level.
When you reach the amplifiers you may need to wear earplugs to adjust them to their maximum level. As before, turn up the gain until you hear audible distortion.

That's it. Play some music and verify that everything sounds right. Congratulations! You've just learned to properly adjust the settings on your car audio system.

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