Do You Really Need a Line Output Converter (LOC)?

Changing your factory sound system can make the drive more enjoyable. When exploring car audio, you will soon see that the term Line Output Converter or LOC, is very important. A lot of install guides or amp kits suggest adding one, but is it something you really have to use?

The short answer: it depends on your setup. Let's break down what a line output converter is, what it does, and whether it’s the right tool for your audio goals.

What Is a Line Output Converter?

Line Output Converter (LOC) is a device that converts high-level speaker signals from your factory stereo into low-level RCA signals that an aftermarket amplifier can accept. Think of it as a translator between your OEM stereo and aftermarket gear.

Factory head units don't typically come with RCA pre-outs, especially in non-premium trims. If you're installing an amplifier but keeping your stock head unit, an LOC allows the two to work together without distortion or signal mismatch.

What Does a Line Out Converter Do?

The core line out converter purpose is to take the amplified signal from your speaker wires and reduce it to a signal level that won't overpower your new amp’s input stage.

Without an LOC, sending high-voltage signals directly into an aftermarket amp’s RCA inputs can lead to:

• Distorted or clipped audio

• Blown input circuitry

• Inconsistent gain settings

• Poor overall sound quality

An LOC fixes this by safely scaling down the voltage, allowing your amp to do its job—cleanly amplifying the sound.

When Do You Actually Need an LOC?

Here’s when a line output converter is not just helpful—it’s necessary:

• Keeping your factory head unit but upgrading to an aftermarket amp

• Your OEM stereo has no RCA outputs

• You want to retain steering wheel controls or built-in vehicle functions

• You're working with a premium factory system with separate factory amps

If your system checks one or more of these boxes, an LOC becomes a bridge between old and new.

LOC vs DSP: Which One Is Right for You?

It’s easy to confuse a Line Output Converter with a Digital Signal Processor (DSP)—especially since some modern DSPs include LOC functionality. But they serve different roles:

If you're just looking to connect a factory stereo to an amp, a basic LOC will do the trick.

If you want the ultimate in fine tuning of your sound or you need to clean up messy factory speaker audio signals, a DSP is the better way to go. A number of DSPs (such as Audiocontrol or Helix models) have high level inputs that basically duplicate what an LOC does, only more (plus much more).

Passive vs Active LOCs: What’s the Difference?

Not all LOCs are created equal. There are two main types:

🔹 Passive LOC

• Simple circuit, no power required

• Just converts signal levels

• Affordable and easy to install

• May introduce noise or lack filtering

🔹 Active LOC

• Powered via 12V

• Includes signal filtering and sometimes remote turn-on triggers

• Cleaner signal, better bass response

• Ideal for subwoofer installs or full system upgrades

If you're running a high-power system or want to retain sound quality, an active LOC is usually worth the extra cost.

Examples of LOC Use in Real Installs

Let’s say you own a late-model Toyota Camry. You like the factory head unit—it integrates perfectly with the dash and includes backup camera and Bluetooth. But the sound is flat, and the bass is weak.

Rather than replacing the head unit, you decide to keep it and add a 5-channel amplifier, new speakers, and a sub. But your factory stereo has no RCA outs.

With such a device, line outputs from the car’s speaker wires behind the dash are converted into RCA signal and sent to your amp. The factory radio is still fixed where it should be and it now supports a higher-quality sound experience.

There is another case: you have a Ford with a premium factory amp with complicated equalization on the speaker outputs. If this is the case, you may just not be able to get away with the LOC alone — you may actually need a DSP to clean up the signal before it goes to the aftermarket amp.

How to Install a Line Output Converter Correctly?

Installing an LOC is a fairly straightforward process, but getting it wrong can mean weak sound or noise issues. Follow these steps:

1. Identify speaker wires behind your head unit or factory amp

2. Use a wiring diagram for your specific vehicle

3. Tap into the speaker wires using solder or T-taps

4. Connect to the LOC's high-level inputs

5. Ground the LOC properly—a poor ground can cause buzzing or whining

6. Run RCAs from the LOC to your amp

7. Set the gain levels carefully—don’t crank it to max right away

8. Test system for noise or imbalance

Some LOCs also include a remote turn-on output. This sends a 12V signal to your amp when the factory stereo powers on, eliminating the need for a separate remote wire.

Common Problems When Skipping an LOC

If you’re tempted to go without an LOC and just use speaker-to-RCA adapters or tap into signal lines directly—proceed with caution.

Here are some problems you might face:

• Distortion at low volume due to input overload

• Popping sounds on engine start

• Blown amp inputs

• Alternator whine or buzz from mismatched grounds

• Loss of factory functions like fader or balance

In short, skipping the LOC usually leads to compromised performance or worse.

LOCs and OEM to Aftermarket Audio Integration

Replacing factory head units is becoming less common as vehicles get smarter and more connected. Those displays are tied into touchscreens, climate controls, backup cameras and even car diagnostics.

That’s why OEM to aftermarket audio integration has become so important. LOCs allow you to:

• Upgrade sound without replacing the head unit

• Keep your vehicle's modern features intact

• Retain factory fit and finish

• Avoid major wiring or coding work

For many newer cars, LOCs aren’t just helpful—they’re essential.

So, Do You Really Need a Line Output Converter?

Yes, you probably do if you’re working with a factory stereo and you want better sound. It’s the cleanest and safest way to bridge OEM systems in between aftermarket amps and speakers.

That said, if you're going for an advanced build with sound tuning, time alignment, or factory signal de-EQing, you might skip the basic LOC and go straight to a DSP.

Ultimately, it comes down to your system goals, budget, and vehicle type.

• Want to add a sub to your stock system? A simple LOC will work.

• Replacing the entire speaker setup while keeping the stock head unit? An active LOC is ideal.

• Want total control over staging, EQ, and time alignment? Consider a DSP with LOC functions built in.

Still unsure what you need? At Elite Auto Gear, we offer LOCs, DSPs, and expert advice to help you build your perfect car audio setup—without guesswork.