Elevating the sound of a factory stereo

In a Nutshell

Modern vehicles often present two problems to their owners. First, the factory stereo system doesn't sound very good. At all. Second, factory "infotainment" systems have all the features that you wanted when you bought the car. You probably don't want to replace the stereo. 

The way around these problems is to add new speakers and a 4-channel amplifier to power them. That'll give you a major overhaul in sound quality. Even then, the presence of an upgraded "Premium" sound system can sometimes make this difficult. 

We found a couple of products that let you keep the factory stereo but gain amazing sound, even with a complex Premium factory system: the AudioControl LC-4.800 amplifier and the Epicenter 600 subwoofer amplifier.* 

Full Story

Picture this:  you've taken the plunge on a new car, and even ponied up for the deluxe infotainment package. You like the tech it offers — the nav, the Bluetooth®, the smartphone integration, and voice control, but the sound quality leaves you feeling as flat as...well, as flat as the sound itself.

If this has happened to you, don't worry: this is a fixable problem. And one that doesn't require replacing that factory stereo, or any of the features you like so much. All it takes is a key upgrade or two. To demonstrate what we mean, we rolled up our sleeves and installed a new ampliifer, subwoofer, and new speakers in a 2016 Kia Sportage with a premium factory system. And it turned out spectacularly.

The Kia in question belongs to Steph, an elementary school teacher. Her dad's a longtime colleague of ours, so she's grown up with plenty of exposure to the mobile audio industry. That's how she knew that the Kia's sound quality just wasn't going to cut it, no matter how much she liked everything else the A/V system had to offer. We were happy to help, and by helping her, help our customers get a sense of what's possible in their vehicles.

Finding the right amplifier for the job

The key to upgrading her Kia was to find just the right amp for the job — in this case, the AudioControl LC-4.800. It offers the kind of hookup flexibility and audio processing that's essential for connecting to and improving the sound of a factory system. Especially a premium system, like the one Steph's car has. But first, a little background.

Better sound needs amplified power

Broadly speaking, adding a 4-channel amplifier to drive new speakers can make a huge difference when you're trying to coax better sound out of a factory radio. Even if you have a factory system with an external amplifier, like Steph's Kia, an aftermarket amp will dramatically increase the power. This is a great thing, because extra power produces more detail and helps overcome the negative effects of wind, traffic, and road noise.

To get the sound from your factory stereo to a new amplifier, you almost always need to tap into the factory speaker wires and connect them to the amp's speaker-level inputs (just make sure you get an amp that has them). This presents a much higher-voltage signal to the amp than the typical aftermarket method of preamp outputs and inputs. The amp then steps the voltage down a bit before proceeding to amplify things.

Other obstacles to overcome — digital signals and extra speakers

Steph's Kia presented a fairly big challenge: the factory stereo sends a purely digital signal to the amplifier, where it's processed, amplified, and sent on to the factory component speakers. That meant that we had to tap into the speaker wires after the factory amplifier, because speaker-level signals going to a new amplifier need to be analog. So we were going to be presenting a pretty high-voltage signal to the new amp.

On top of that, the factory amp in her Kia has separate outputs for the woofers and tweeters of the factory component system, with only high frequencies going to the tweeters, and lower frequencies going to the woofers. Most 4-channel amps with speaker-level inputs only offer one set of each for front and rear channels. This posed the potential problem of leaving out an entire range of frequencies.

So, to summarize: we couldn’t use the signal coming into the amp because it’s digital and we need analog. The output side is split into highs and lows coming straight out of the amp, and most amplifiers can’t deal with that.

Enter the AudioControl LC-4.800 — a true problem solver

The AudioControl LC-4.800 provided the ideal solution to both of these issues. First off, its speaker-level inputs will handle up to 400 watts, which is huge. Handling the amplifier signal from the Kia's amp would be no problem.

But even more importantly, the LC-4.800 offers separate high- and midrange speaker-level inputs for the front channels, specifically to accommodate premium systems like these. When both of these inputs are in use, the amp combines the ranges of the two inputs and sends out one full-range signal that doesn't leave anything out. That's the big reason we chose this amplifier — there aren't many other aftermarket amps that can do this.

Making the input and output connections

Here's what I did. With the help of our tech support department, I identified which wires coming out of the factory amp went to which speakers (this sort of help is available to all of our customers, incidentally). Then, I got a little creative.

I knew that the same set of wires from the car’s amp were going to be used for the AudioControl amp’s inputs and outputs. Basically, I was going to have to cut each wire, connect new wires to each end, and run these two sets of new wires to the AudioControl amplifier:

• The connection from the factory amplifier would go to the appropriate speaker-level input on the AudioControl amp.
• The other connection would go to the appropriate AudioControl output, and send signal to the speakers.

The right speaker wire for the job

To make life easier, I used EFX's 9-wire cable, which is a lifesaver when doing installations like these. The wire colors match the standards for aftermarket speaker outputs: white for front left, gray for front right, green for rear left, and purple for rear right. I used this same color strategy for the each of the front and rear inputs.

For the dedicated factory tweeter wires, I used lengths of wire with colors that weren't in the 9-wire bundle (and wrote down the color codes on the same sheet of paper that listed the factory wire colors). That helped keep me from getting confused when working with all of these different strands.

After clipping each factory speaker wire, I connected each new wire using a Posi-Products connector. That made for a clean, easy, connection without having to negotiate with a soldering iron and solder in the cargo area. My un-accidentally-burned skin thanked me later. With all the input wires connected, next I plugged each of them into the AudioControl's speaker-level input harness, then plugged the harness into the amp.

For the speaker outputs, I used another length of the 9-wire cable, connecting one end of each of the wires to the speaker outputs of the amp, then the other end to the factory wires, again using Posi connectors, and again following the standard aftermarket wire-color scheme. Because I only needed four sets of connections this time, each offering the full range of frequencies, I simply taped off the ends of the factory tweeter output wires going to the speakers, as they'd no longer be used.

High-end speakers to handle the new power

Since Steph didn't want to mess around with inferior sound, the choice of replacement speakers was obvious to her: AudioFrog. Generally speaking, these boutique speakers offer rich detail, and warm, inviting tone. They'll also handle a whole lot of power, making them great matches for the 125-watt RMS LC-4.800 amplifier.

As I mentioned above, Steph's Kia came with factory component speakers. However, AudioFrog tweeters are a bit too big for the factory tweeter locations in the sail panels, and Steph wasn't too keen on modifiying her still-new door panels (which was totally understandable). So we opted for the GS62 coaxials, which we knew would fit in her doors neatly.

To install them, I had to do a little bit of drilling, both to remove the rivets that attached the factory speakers, and to create a couple of new screw holes. But once that was all done, the Crutchfield-supplied speaker wiring harnesses slid on tightly, and the speakers mounted neatly.

To my surprise (though maybe I shouldn't have been), the soundstaging with these speakers was astonishing. Despite being mounted somewhat low in the doors, it sounded to my ears that the stage was nice and high, as though the band were playing right on the dash, exactly where you'd want it to be. That's a strong testament to the admirable quality AudioFrog brings to the mobile A/V arena. Without doing much tuning, I could hear a tremendous amount more detail, and the volume ceiling was much, much higher.

Improving the Kia's bass performance

Steph's Kia came with a factory subwoofer mounted behind the right-side panel in the cargo area, but it just wasn't giving her the bass she really wanted. AudioFrog and AudioControl to the rescue again.

To give her new sub full, dedicated power, we added an AudioControl Epicenter 600 mono amplifier* into the mix. It brought two main benefits to the table. First, it features AudioControl's Epicenter bass restoration technology. It's often the case that factory stereos limit the bass level as you raise the volume to keep from damaging the cheap factory speakers found in most cars. Epicenter technology keeps that from happening when you use it with aftermarket equipment.

Second, the Epicenter is 1-ohm stable. You can read more about subwoofer impedance in our handy article, but suffice it to say that the less impedance you "show" an amp, the more power it sends to your sub, and the louder and harder the sub will play. Now, both the sub and the amp need to be 1-ohm stable for this to work without damaging anything, but when it works, if it's bass you're after...well, you've come to the right place.

To get signal to the Epicenter, I used Posi-Products taps to splice into the factory sub's input wires, which I identified again with the help of our tech department. Here I went with wires that matched the factory colors to keep things clear and easy, and plugged them right into the amp's speaker-level input harness.

Adding the subwoofer

Next, it was time to connect the sub to the Epicenter — in this case, an AudioFrog GS12D2 12" sub* with dual 2-ohm voice coils. This allowed me to wire the voice coils in parallel to achieve a 1-ohm load. I connected it to the amp's speaker outputs, fired up the system, and...holy moly. The sub began pounding, even with the amp's gain set all the way down. It hit hard, played loud, and, after setting the low-pass crossovers to about 75 Hz, played with satisfyingly musical accuracy. Oh, it was good. 

*Note: As of January 2020, both the AudioControl Epicenter 600 amplifier and the Audio Frog GS12D2 subwoofer are discontinued and unavailable for purchase. Substitute products include an AudioControl LC2i line output converter with AccuBASS bass restoration, an AudioControl ACM-2.300 amplifier, and an Audio Frog GB12D2 subwoofer.

A note on amplifier installation

As far as power goes, when you're connecting an amp to a factory stereo, you'll still need to run power wire to the vehicle's battery, and a ground wire to the vehicle's chassis. In Steph's Kia, I ran 1/0-gauge cable from the battery and passed it through the firewall by cutting a hole in a gasket that was already allowing factory wiring to enter the vehicle's cab (I sealed the hole around the power wire with silicone to make sure no water can get in). For the ground, I used a seat belt bolt in the back seat, making sure to scrape away enough paint to allow the terminal ring to touch bare metal.

With both the power and ground wires, I used distribution blocks. The 1/0-gauge wires from the battery and ground locations went in one side, and out the other side ran the 4-gauge wires that connect to the amplifiers. Distribution blocks are incredibly helpful when you're dealing with a multi-amp installation because they allow you to make just one power and one ground connection to the car.

If you'd like more information about what goes into wiring and mounting amps, be sure to check out our amp installation guide, which neatly covers the basics.

What about your car? 

If you're ready to ditch the factory sound while keeping your factory stereo, be sure to give one of our highly trained advisors a call at 1-888-955-6000 to make sure you get everything you need. All Crutchfield purchases come with free lifetime tech support, which means installation guidance and advice is just a phone call away.