How to upgrade your car's head unit and speakers
While many cars have fairly decent stereos from the factory, they seldom satisfy the discerning audio consumer. No matter if your car is 12 months or 12 years old, you'll get more sonic pleasure if you take the time to upgrade your in-car audio. Best of all, it need only cost a few hundred dollars or less.
Given the breadth of what can be covered in car audio, this article will cover upgrading your source (head unit) and speakers, while we've also spoken about how to upgrade your car's amplifiers, subwoofers, and beyond.
Current Set Up
On deciding what to upgrade, you first need to look at your current system. Many contemporary vehicles have fully integrated control units that combine the stereo with climate control, navigation, etc. These are generally better to leave installed, upgrading only the speakers.
However, there are ways to add in amplifiers to these units, too, which we'll get to in a moment, and professional installers can offer options that will work your climate control and steering wheel buttons, too.
When considering budget, don't be afraid to perform your upgrades incrementally, starting with the front speakers. This way, you can save up for higher quality components, while also trialling your system to find the parts that most need upgrading.
We recommend planning a rough idea of what your ideal system would look like, and then buying parts that will support it later (for example, your new front speakers can always become rears after you buy quality component speakers).
As a rough figure for a budget system, expect about AU$150 (approx £74, US$108) for the head unit (the bit that plays the music) and AU$150 (approx £74, US$108) for the speakers.
If you're going premium, the head unit will cost between AU$200 and AU$1400 (approx £92-£647, US$144-$1008) depending on the features you want, and then about AU$200-$600 (approx £92-£277, US$144-$432) for good component speakers (Hertz, Focal, JL Audio et al.), and AU$200-$600+ (approx £92-£277, US$144-$432) for an amplifier to drive them. You can then expect another few hundred dollars or more for a subwoofer – you can see that the price quickly escalates.
Regardless of how much you want to change in your current car stereo, the first place we recommend looking at is the speakers. Speakers are the biggest influencer of sound quality, and factory speakers – even the 'premium' ones – rarely compete with the quality of aftermarket components.
Thankfully, it's actually surprisingly cheap and easy to upgrade your speakers – you can drop about AU$150 (approx £69, US$108) on a pair of perfectly adequate ones, and it shouldn't take you more than an afternoon to install them.
When choosing speakers, you need to see if they will fit in the existing holes. Don't forget that the depth of the speaker, as well as how far it sits from the cone, can affect how well it will fit in the door. You may end up having to cut a larger hole, or building a mount to lift the cone out.
You also need to consider the speakers' power-handling. Look at their rated RMS value, and – if you're going to purchase an amp – make sure that the speakers' max value is near or below the RMS output of the amplifier.
If you're going to attach them directly to your head unit, then pretty much all speakers will work fine (note that premium and component speakers are happier with external amps, though), and if you're going to stick with your car's factory head unit, you'll probably be best off finding high-sensitivity speakers, as factory units generally don't offer as much power as third party ones.
Speakers: Different Types
You may be tempted to get some 6x9" oval-shaped speakers for the rear shelf. These can offer bigger bass than 6" speakers, without taking up as much room as larger ones. However, they're a trade off in bass quality compared to circular speakers. As such, if you see a subwoofer in your future, stick to round speakers.
If you're looking for el-supremo sound, then you should consider component – rather than full-range (aka two- or three-way) – speakers. These break the woofers/mids and tweeters into separate components, to be placed individually.
This gives you better fidelity, but is a more complicated install – expect much cutting of your interior, as well as extra wiring of cross overs and running cable to new and exciting places in your dashboard, doors, and floor. As such, you may be best leaving it to a professional.
Now, the next most useful upgrade is your head unit. As mentioned earlier, if you have an integrated stereo, you may be better off leaving it as is and just adding new speakers or an amp (if your stereo doesn't have pre-amp outputs, you will require an amp with speaker-level inputs or a separate digital signal processor). To see what's possible, try searching for your model on car audio forums.
Most head units, however, comply with the 50mm tall 'DIN' or 100mm 'Double DIN' standard found in cars since 1984. Even if your existing stereo is a single DIN size, you may be able to remove a storage unit above or below it to fit in a double-DIN unit, which can open you up to touch screens with navigation or the ability to watch movies etc.
The head unit is actually less important a consideration than it once was, as most people use their smartphone for music and navigation, so really just need Bluetooth. However, there are still some very important considerations to make, even if its sole purpose will be to control the volume.
Head Unit: Sources
First of all, you need to think about what sources you may want to use. You absolutely definitely want Bluetooth – thankfully, it's standard now. Also, while CDs are a rarity, I often stop in at op-shops on road trips to see what hidden gems lie within (last summer I found a Christmas carol album composed from cat and dog calls for the stunningly low price of 50c – let's just say that it was worth at least twice that amount) – times like this you may be grateful for the ability to spin some plastic.
Also worth considering is if you want to get use out of your old iPod (or current – we're not judging), so look for iPod connectivity.
For flexibility, I also like my head units to have a 3.5mm auxiliary jack on the front, so that I can connect anything I want – an mp3 player, my phone (if I want a higher quality connection or to save battery) or even a Walkman (cassettes are back now, didn't you know?).
Some head units even offer their own app store like the Parrot Asteroid Smart, or have Android or iOS companion apps available (the quality of which is variable). The coolest of the lot, for iPhone users at least, are head units that support CarPlay.
Head Unit: Usability
When choosing a head unit, one super very important feature is often overlooked: usability. Some head units are painful to use, so it's important to go down to a retail store and play with any that you're interested in. Quite often, the cheapest brands are more hassle than they're worth, especially when it comes to playback from USB storage.
If you're planning on adding an amp or subwoofer, confirm that the head unit has pre-amp and/or subwoofer outputs. While amps exist with speaker-level inputs, these are more difficult to wire and end up with poorer sound, so – even if an amp is only a slight possibility – make sure you get pre-amp outputs.
While we're on the topic of future-proofing, you may want rear line-level inputs, just in case your music source of the future isn't Bluetooth (for instance, you may want to add a Raspberry Pi based carputer, or hard wire in a tablet).
Surprisingly, the power output of a head unit isn't as important as it seems. Of course the more expensive head units boast bigger numbers, but they're all loud enough to drive your four 6" front and rear speakers. If you're really serious about volume (or fidelity, really) you're going to fork out for a separate amp, anyway, so just get the head unit with the sources, interface, and aesthetics that you like best.
Head Unit: Additional features
The rest of the features sorta just end up as extras: if you're keen for proper surround audio, you'll probably want a DVD player in there with digital output. If you're doing that, you'll probably want a decent screen/monitor, too.
And, again, if you're doing that, then you'll want to check if you can have multiple screens connected. Some even allow different videos and audio output for the front and rear, but, with the proliferation of tablets, this is less useful than it used to be.
Some head units include navigation, but so does your phone. You may also be tempted by a unit with a hard drive inside, which you can fill with music, but I find loading them up with new tunes a cumbersome act, so prefer my iPod for bulk media storage. You may also enjoy a large touchscreen, but these can treble the cost.
Wiring it up
If you're only upgrading your speakers, the great news is that you can just connect the existing wires to the speaker terminals, just be sure to connect the wires the right way around – usually, black or striped is negative – and be consistent between speakers.
To remove your speakers, you're going to have to first remove your door trim. There are usually pop-studs around the edges of the door, and a few screws in the door jam and behind the arm rest or handle. To get specific instructions for your make and model, find either a service manual, do a Google search, or search in your preferred car audio forum.
Once you've unscrewed your old speakers, you'll probably have to cut the wires leading to them. If you're intimidated by soldering irons, you can easily hook up the new speakers by using terminal strips – just screw down the wires on either side. This means it'll be easy to replace them next time, too. Just make sure that you secure the terminal strips to the car, lest you hear them rattling against the cone or door frame on bass notes.
If you're upgrading your head unit, we recommend purchasing a wiring harness set for your particular model. These form a bridge between your car's wiring harness and the connections on the rear of the head unit. One manufacturer is Aerpro, and they are available from most car audio stores, but also from specialty online stores and eBay.
If you're frugal or can't find the right harness, you can remove the old harness and connect the wires directly. Again, just like the speakers, we recommend using terminal strips or other plugs so that the head unit is easy to remove when you sell the car or upgrade.
To identify which wires should go where, you'll need the service manual of the vehicle, or a multimeter and some sleuthing skills. A thorough yet simple methodology is available at the12volt.com.
But first, to get the factory stereo out, you're probably going to have to remove part of dashboard. Again, consult your service manual or car specific forum for tips on how to do this – don't fret, though: it's not nearly as hard as it seems!
You should now be armed with enough knowledge to undertake a basic car stereo upgrade. Join us in a future article where we'll take your system to the next level by looking at amplifiers, subwoofers, and more.