What Does a Car Subwoofer Do?

If you’ve ever sat in a car and felt the music in your chest, chances are, a subwoofer was responsible. Subwoofers are the secret sauce behind deep, punchy bass that makes your music come alive. But what exactly does a subwoofer do—and do you really need one in your car audio system? Let’s break it down.

What Is a Subwoofer?

It’s All About That Bass

A subwoofer is a speaker specifically designed to reproduce low-frequency sounds—what we usually call bass. These are frequencies typically between 20 Hz and 200 Hz. Think of the rumble of a kick drum, the thump of a bass guitar, or the low-end in hip-hop, EDM, and pop tracks.

While your regular car speakers (called full-range speakers) try to handle highs, mids, and lows all at once, they often struggle with the lower end. That’s where a subwoofer steps in to take over the bass duties and let your other speakers focus on mids and highs.

Why Your Music Needs a Subwoofer

1. You Get the Full Frequency Spectrum

Most music is mixed with a full range of frequencies, from highs and mids to deep bass. Without a subwoofer, you’re missing out on a huge chunk of that spectrum. Even if you’re not a “bass head,” a subwoofer rounds out your music and gives it depth and warmth.

2. Better Sound Balance

Adding a subwoofer doesn’t just make your bass louder—it makes your entire system sound better. When your main speakers don’t have to work as hard to produce low-end sounds, they can perform more efficiently. This creates a more balanced and dynamic listening experience.

3. More Impact and Emotion

Bass adds impact and emotion to your music. Whether it’s the chest-thumping drop in an EDM track or the smooth groove of a jazz bassline, a subwoofer helps you feel the music—not just hear it.

How Does a Subwoofer Work?

Subwoofers use larger cones than traditional speakers, often ranging from 8 to 15 inches. These bigger cones can move more air, which is essential for creating deep, low-frequency sounds.

Most car subwoofers require an external amplifier because reproducing bass takes power—more than most factory head units or door speakers can provide.

Types of Car Subwoofers

1. Component Subwoofers

These are raw subwoofer drivers that you mount in a custom box. They offer flexibility in terms of size, enclosure type (sealed, ported, bandpass), and amplifier pairing.

2. Powered Subwoofers

These combine the subwoofer and amplifier into a single enclosure. They’re great for tight spaces or simpler installs but usually don’t offer the same power and output as separate components.

3. Enclosed Subwoofers

These come pre-mounted in a box but don’t include an amp. They’re a good middle ground—easy to install with more flexibility in choosing your amplifier.

What Size Subwoofer Should You Get?

It Depends on Your Space and Preferences

  • 8" or 10" subs: Great for tight spaces or subtle bass. Perfect if you want clarity without overpowering your music.

  • 12" subs: The sweet spot for most people—powerful, punchy, and still clear.

  • 15" subs: Serious bass for SPL setups or bass lovers who want to shake the block.

Do You Need an Amp for Your Subwoofer?

In most cases, yes. A subwoofer needs more power than your typical car speaker. An external amplifier ensures it gets the wattage it needs to hit those deep, low notes without distortion. Just make sure the amp and sub are properly matched in terms of power (RMS watts) and impedance (ohms).

Where Should You Put a Subwoofer in a Car?

Common Locations

  • Trunk – Most common and easiest to install

  • Under a seat – Perfect for compact or powered subs

  • Behind the seat – Great for trucks and smaller vehicles

Placement affects sound, especially bass response and resonance. Experiment with location to get the best result—or work with a professional installer for optimal performance.

The Soundstream Advantage

Soundstream offers a wide range of car subwoofers—from compact models to high-output beasts designed for maximum SPL. Built with durable materials and designed for tight, musical bass, Soundstream subs are trusted by pros and enthusiasts alike.

Pair your Soundstream subwoofer with a matching Soundstream amplifier and you’ve got a system that hits hard, sounds great, and stands the test of time.

Conclusion: Car Subwoofers

So, what does a car subwoofer do? It gives your music the low-end foundation it needs. Whether you're after window-shaking bass or just want to bring your sound system to life, a subwoofer is a must-have for any serious car audio setup.