How to Set Up a Car Audio Sound System

Back in the old days, setting up a car sound system was simply a matter of buying a pre-made speaker box and an amplifier. Plug in your speaker wires then hook up the power to the amplifier and off you’d go. Today, it’s not too much different, but the amount of power that an amplifier can generate and the speakers can handle can literally shake the windows out of your car. Where to begin? There are a myriad of possibilities and configurations to choose from. You can pretty much get whatever you want depending on your budget, but we recommend you figure out what it is you really want first.

Do you want just a little more bass? Do you want to have clearer sounding instrumentals? Do you want everyone to know you’re coming from 2 blocks away? Once you’ve answered those questions, next you have to analyze the system you have now. Do you have a good stereo but the speakers sound bad? Do you have great speakers but the stereo needs and upgrade? Are they both on their last legs? Next up is the budget. How much do you want to spend on all of these components? For example, it used to be common to spend anywhere from $700 to $1000 on a 2-channel amp. Nowadays, you can find a quality 5-channel amp for less than $300.

In this discussion, we will delve into the things you need to know when it comes to building a sound system for your car. We will talk about the components that make up an aftermarket system, and how to actually set up a car audio system. While setting up a car sound system can be very complicated, we will try to keep it as simple and straightforward as possible.

How to set up a car audio sound system

The stereo receiver unit

This is essentially the brain of your system. The car stereo receiver is the part of your sound system you will interact will most often, so let’s start there. The receiver you purchase should have RCA pre-amp outputs — RCA pre-amp outputs will make it easier to run the wires through your car to the amplifier without having a wire for every speaker terminal. Stereo receivers with Bluetooth is a common and useful feature. This will allow you to use your phone as your stereo. These units are typically cheaper, and if you don’t really need all the bells and whistles of a more expensive unit then this would be a good option.

Just make sure that the unit has a USB plug, as this will also allow you to charge your phone while you drive. The really great part of having a Bluetooth stereo is that if you have a service like Spotify or iTunes, you can take your music straight from the street to the car. If you want to take it to the next level, then you’d be looking at a premium dual or double din DVD/CD Bluetooth touchscreen unit. Ultimately, we couldn’t ever picture our lives without a receiver with Bluetooth from here on out.

So what does ‘DIN’ mean when it comes to car audio receivers? Car stereo decks are basically broken down into two forms, a single DIN and a double DIN. A DIN is just the slot that the stereo fits into. Your first car stereo was most likely a single DIN — when you think of car stereos, the single DIN is what will come to mind first. A double DIN is just double the height of the single din, or a traditional car stereo we all picture in our heads. A seven-inch (18 cm) touchscreen stereo would be a double din unit.

The touchscreen is another of those great features that allow you to keep your attention where it belongs, on the road. Most stereos today also have a hands-free feature giving you the option of simply speaking out instructions like making phone calls, changing stations, selecting specific songs to play and even adjusting the equalizer. Now, for most of these aftermarket units the maximum output power is about 55 watts which is why you would want an amplifier to boost the signal.

Obviously, most of the double DIN stereo units have GPS navigation as a baseline feature and just about everyone has one on their cell phones, so there’s not really a need to talk about it here. With a 7 inch display there is also the possibility of RCA outputs so you can watch movies either from your phone, pad, the display itself or seat mounted monitors. We of course don’t recommend watching YouTube while you drive!

The car amplifier

Up next, the car amplifier (or amp) is in our opinion the second most important part of your car sound system. It drives the power to the speakers and is the heart of your rig. As the interface between the speakers and the stereo unit, it’s responsible for managing the amount of power (or watts) to each speaker of your system. This is where it gets a bit technical. What you’re looking for in an amp is the maximum RMS rating. RMS stands for Root Mean Square, and is the amount of stable, continuous power the amp can produce. The same RMS rating applies to speakers too, and this formula works the same with them. Take that maximum RMS number and multiply it by 0.75. The number of channels you plan to have (2, 3, 4 or 5 channels) on your amplifier doesn’t matter. This will give you the minimum number of watts the amp has for each channel. Now simply multiply the minimum RMS number by 1.5 and it will give you the maximum power output that you actually send to each channel.

Speaking of channels, a 5-channel amp will allow you to power two front speakers, two back speakers and a subwoofer. A 4-channel amp will allow you to either power two fronts and two rears or two rear speakers and a subwoofer. For the two rears and subwoofer though, the configuration does require an amp that is “bridgeable”. A bridgeable amp lets you combine or “bridge” two channels together to double the power output to a single speaker. A 3-channel amp is purpose-built for the two speaker one subwoofer configuration above, it doesn’t need a bridge. Finally, the 2-channel amplifier is for those who want either all front speakers and no rears or all rears and no front speakers. Another thing to keep in mind is to make sure the new amp you buy also has RCA input and outputs. Most do these days, but it’s something to keep a look out for (it will make speaker/receiver installation easier later).

The car speakers

Car stereo speakers are where the rubber meets the road when it comes to building a sound system for your car. First, you have to figure out what type of system you want to install, then picking speakers to maximize their sound reproduction and life span. When purchasing new speakers, there are a few considerations that must be taken into account. What type of speakers to use in the system, component speakers or full-range speakers? Full-range speakers are commonly called coaxial speakers and are a combination of a mid-range woofer and a tweeter in one speaker. The tweeter is what gives you the high frequency sounds (voice, horns, etc.) and the mid-range woofer gives you the lower frequency sounds like bass.

Coaxial speakers come equipped with a small crossover attached to the input terminal. A crossover acts as a splitter between the high and low-frequency ranges, separating them and giving you a clean low distortion sound from both levels. Full-range speakers are typically less expensive than component speakers and you also have your bass and your vocals coming from the same direction. The component speakers separate the tweeter from the mid-range so you can mount them in different places. Component speakers also require a separate crossover which could be a good thing if you plan to use an amplifier with a built-in crossover. Be sure to buy speakers that will fit into the spot your current speakers are in, unless you plan to build or buy a speaker box. This will make installation easier later.

A subwoofer for cars is one of those personal preference items. Could you get by without it? Yes. However, until you’ve had one you don’t know what you’re missing. If you have a smaller car, then you wouldn’t really need a large 15 inch (38 cm) subwoofer. An 8 inch (20 cm) will give you plenty of deep bass for your car. Besides, subwoofers can use frequencies that are lower than the human ear can actually hear and you could damage your hearing if you use too much bass in an enclosed space.

Installing the car sound system

So you’ve bought all of your components and are ready to go. What’s next? Well, you will need the right equipment. You’ll need a fully charged screwdriver (unless you want to go old school), a socket wrench and a spool of speaker wire for the new connections. You’ll probably want a 4 gauge wire if you’re going with a big amplifier (1000 watts) but 6 to 10 gauge if you’re 800 watts or lower (the lower the power, the higher the gauge). You will also need wire strippers and some female to female and female quick slide-wire connectors if you want the connections to be clean. Some small metal screws may also be necessary to install the amplifier. Obviously because there are so many different cars and truck that all use different connectors for the stereo, we will only discuss basic installation here. First, disconnect the car battery. Pull one of the door speakers and look for the color of the wires. This will help you understand how your car manufacturer set up the wiring to the stereo.

Next, remove the other door speaker and see if the wires are the same color or different. Now you can pull the stereo and look for those colored wires from the door speakers. They should be in a harness that connects to the back of the stereo. Repeat the speaker removal process for the rear speakers, by the time you’re done with that you will know right side speakers from left and front speakers from back. Find the ground and the main power from the stereo. The power is usually red and the ground is usually black. Disconnect the wire harness from the back of the old stereo receiver and unscrew the ground wire (replace the screw so you don’t forget where it goes later). Cut and strip the red power wire and remove the old receiver. Before installing the new unit, install the speakers in their correct places and if you need to, strip and attach the female quick slides or some of the more fancy connectors you can find online to the wires making sure you connect the solid color wire (or red) to the positive (+) and the striped wire (or black) to the negative (-) posts on the speakers.

Once that’s done, connect the wires according to their color to the back of the receiver and attach the RCA cables to the RCA outputs (the new receiver should have come with a long RCA cable, but you may have to purchase one if it wasn’t included). Run the RCA cables down the driver’s side of the car to avoid signal interference from the amplifier power cable. Installing the amplifier can be a tricky prospect. It requires a direct line to the battery which means running a long, heavy gauge wire through your car interior to the engine compartment and down to the battery. Most cars have a hole in the floor in the front passenger side fire wall floor board where the electrical for the dashboard, etc. goes. You may have to drill one, but it should not be necessary. Amplifiers come with a long power wire and a fuse box to protect the rest of your car. Install the fuse box close to the battery. Run the red power wire from the battery through the hole in the floor board and down the passenger side of the car interior. Be sure not to connect the red wire to the battery yet. You should be able to tuck the wires away, but you may need to remove the lower door seals on the floor to get the wire under.

Typically it is best to install the amp in the trunk, and that’s where the metal screws come in. If you have a speaker box, then it’s easy to screw it into the box, but if you don’t then you will need a secure place to install. Find a spot in the trunk or cargo area on the battery side of the vehicle where a small screw won’t punch a hole in the outside of your car and mount it. Find a good ground in the trunk or cargo area. It should not have any paint on it because the paint won’t conduct electricity.

Next up will be the auxiliary power from the amp. The color varies from manufacturer to manufacturer and it just runs to the power wire on the stereo receiver to shut off the amp when the stereo is off. Plug in the RCA cables to the amp and connect the amplifier power cord to the vehicle’s red battery harness. Connect the red power wire from the old stereo to the red power cord on the new stereo and install the stereo receiver into the dash. Reconnect the battery, turn on the car and test the system.

In the end, setting up a car sound system is fairly straightforward and not something you should be afraid to do yourself. Soon you’ll be rolling down the highway enjoying your favorite tunes with the pride that comes with a job well done.