How to Connect a Subwoofer to a Car Stereo Without an Amp

How to Connect a Subwoofer to a Car Stereo Without an Amp
11th Dec,2019

Installing an amp to your car stereo system will significantly boost your bass. In most cases, subwoofers already come with an amplifier to enhance the sound. But what if the subwoofer you bought didn’t come with an amp, did you just sink money into a device that is now useless? Luckily, no. In this guide, we’ll teach you how to connect a subwoofer to a car stereo without an amp.

What You Need

Before we take you through the step-by-step process of how to connect everything, here are the necessary tools you need:

  • Tester
  • Spanner and a hammer
  • Screw and pliers

How to Connect a Subwoofer to a Car Stereo Without an Amp – The Steps

Disconnect the Speaker

Your first step is to disconnect the speakers. First, disconnect your battery and shut off the infotainment system to avoid accidental shocks. You need to remove the speaker from the dock and gain access to the wiring underneath. 


The next part is quite simple. Connect the LFE (low frequency effects)  jack to the output port of the subwoofer. It might be labeled “subwoofer” or “sub out”. This label is for subwoofers only and is usually the only RCA port, which makes it easy to identify.

If you’ve successfully connected your subwoofer, skip to the last paragraph of step 3.

Other Connections

If you don’t see the LFE output or the subwoofer is missing the input, try to find the left and right stereo connectors (sometimes labeled as R and L). If the Line In uses cables, just plug it into the L or R on the subwoofer box. However, if you have two split ends on the cable, plug it into both the L and R.

Make sure the poles are right, negative with negative and positive with positive. This is when your tester comes in handy for you to test the flow of the electrical current, just to make sure the crossover and everything is running well.

Enclose the Subwoofer

Once everything is done and the connection is flawless, enclose the subwoofer and place the speaker back in its holding. Now, you should be free to enjoy your music with thumping bass!

Just to give you a little bit of extra help to ensure you get the most out of your new stereo system, we’ll introduce the different kinds of subwoofers for you to make an informed decision. 

Types of Subwoofers

When asked what kind of subwoofer you want, you’re likely to think you want the “best” one. But what is the “best one”? How do the top 8-inch subwoofers differ from other kinds? The subwoofer you get depends on your car, the type of bass you want, and of course, your budget. So, let’s take a look at what you can find in the market.


A powered subwoofer already has built-in amp which saves you time and space. However, the drawback is it may not pack as much power as one with an external amp, such as some of our top picks for 5-channel amplifiers. For those that aren’t looking for precision, powered subwoofers are great.

Subwoofer for Drivers

These are the basic types that come in an enclosure. However, these options need an external amplifier to power it. 

Vehicle Specific Subwoofers

Some subwoofers are made specifically for your car. If you have a smaller more compact car, these subwoofers would be helpful. They take space-saving into account as well as the budget and appearance. If stealth is your priority, consider these top under seat subwoofers for your car,

How to Pick the Right Subwoofer for Your Car

You know which subwoofer you like and you think it’ll look good sitting in your car, but is it right for your vehicle?

You need to check the enclosures first. Some subs come with an enclosure and some do not. There are two main shapes, with round subwoofers being more common on the market. However, if you have had a chance to look over some of our best subwoofer lists, then you would see some square options too. The square counterparts are considered much more durable and better performing. Some models are even compatible for installation to a factory stereo.

Conseider the voice coils as well. Some are single and some are dual, which offer you more flexibility with wiring. Finally, sensitivity rating is also important as that directly affects the power required to operate and thump out the bass.


You don’t necessarily need an amp for your car subwoofer. Sometimes, size is more of an important factor, and this is something you can try with the greatest shallow mount subwoofers. However, amps help with the sound levels and the bass. If your newfound subwoofer doesn’t come with an amp, it could be tiring to find one that does and you do need certain know-how to do it. Find one that’s relatively easy to set up to give yourself peace of mind and with the least amount of stress possible. 

William Johnson

William Johnson is the owner and founder of He writes about car accessories, with his passion stemming from a deep enthusiasm for all things automotive. His website, RRD, focuses on in-depth reviews of car accessories to help people find the best and latest products in the market.