Learning how to put subs in a car is a fantastic way to upgrade your driving experience. Adding bass to your car’s sound requires connecting an amplifier and subwoofer to your head unit. This guide will walk you through the entire process, from choosing the right gear to the final connection, in clear, simple steps.
You do not need to be a professional installer. With some patience and the right tools, you can achieve great results. We will cover everything you need to know to get that deep, powerful bass you’re looking for.
How To Put Subs In A Car
This section provides a complete overview of the installation process. We will break it down into manageable stages, ensuring you understand each step before moving on. Proper planning is key to a successful and safe installation.
Essential Tools And Materials You Will Need
Before you begin, gather all necessary tools and materials. Having everything on hand will make the job smoother and prevent interruptions. Here is a comprehensive list.
- A subwoofer (or subwoofers) in an enclosure (box)
- A compatible car audio amplifier
- A wiring kit (this is critical and includes power cable, ground cable, remote turn-on wire, RCA cables, and speaker wire)
- Your car’s head unit (stereo), which may need preamp outputs (RCA jacks)
- Line output converter (LOC) if your head unit lacks RCA outputs
- Basic hand tools: screwdrivers, wrenches, socket set, wire cutters/strippers, crimping tool
- Safety glasses and gloves
- Multimeter for testing connections
- Drill with assorted bits
- Electrical tape, heat shrink tubing, and cable ties
Choosing The Right Subwoofer And Amplifier
Selecting compatible components is the first real step. The subwoofer and amplifier must work together. Mismatched equipment can lead to poor sound or even damage.
Understanding Subwoofer Specifications
Pay close attention to the subwoofer’s power handling, measured in RMS watts. This is the continuous power it can handle. Ignore the peak power rating. Also consider the impedance (ohms), typically 2 or 4 ohms, and the size (10″, 12″, etc.) which affects the type of bass.
Matching An Amplifier To Your Subwoofer
Your amplifier’s RMS power output should match your subwoofer’s RMS power handling. Aim for as close as possible. Also, ensure the amplifier’s stable impedance rating matches your subwoofer’s final impedance. This ensures efficient power delivery.
Planning The Installation Layout
Decide where each component will go before running any wires. This prevents wasted effort and ensures a clean setup. Think about space, safety, and accessibility.
- Subwoofer Box: Typically placed in the trunk or rear cargo area. Secure it properly so it does not move while driving.
- Amplifier: Mount it in a location with good airflow to prevent overheating. Common spots include under a seat, in the trunk, or on the back of a rear seat. Avoid damp areas.
- Wire Routes: Plan how you will run the power cable from the battery to the amp, and the RCA/speaker wires from the head unit to the amp and sub.
Step-By-Step Installation Guide
Now, let’s get into the actual installation. Follow these steps in order for the safest and most effective results. Take your time and double-check each connection.
Step 1: Disconnect The Vehicle Battery
Always disconnect the negative terminal of your car battery before starting. This is the most important safety step. It prevents short circuits, electrical shocks, and damage to your vehicle’s electronics.
Step 2: Run The Power Cable
Run the main power wire from the positive battery terminal through the car’s firewall and into the interior, all the way to the amplifier location. Use an existing grommet if possible. Protect the wire from sharp edges with loom or tape. Connect the fuse holder within 18 inches of the battery terminal, but do not install the fuse yet.
Step 3: Establish A Ground Connection
Find a solid, bare metal point near the amplifier. Scrape away any paint or rust to ensure metal-to-metal contact. Attach the ground wire from the amp kit here using a ring terminal and a solid bolt. A poor ground is a common cause of amplifier problems.
Step 4: Connect The Remote Turn-On Wire
This thin blue wire tells the amplifier to turn on with the head unit. Connect it to the remote turn-on lead behind your stereo (usually a blue or blue/white wire). If unsure, consult your head unit’s manual.
Step 5: Run RCA Cables And Speaker Wires
Run the RCA cables from the head unit area to the amplifier location. Keep them as far away from the main power cable as possible to avoid engine noise. Also, run the speaker wire from the amplifier location to where the subwoofer box will be placed.
Step 6: Connect The Head Unit Side
If your head unit has RCA preamp outputs, connect the RCA cables directly. If it does not, you will need a line output converter. The LOC taps into your car’s rear speaker wires to create a signal for the amp. Follow the converter’s instructions carefully.
Step 7: Wire The Amplifier
At the amplifier, connect all the wires. Connect the power wire to the amp’s B+ terminal, the ground wire to the GND terminal, the remote wire to the REM terminal, and the RCA cables to the INPUT section. Finally, connect the speaker wire from the amp’s output terminals to the terminals on the subwoofer box.
Step 8: Wire The Subwoofer To The Box
If you have a separate sub and box, connect the subwoofer to the terminals inside the enclosure. Ensure the positive and negative terminals on the speaker match the terminals on the box. Use a secure connection to prevent vibration from loosening them.
Step 9: Reconnect Battery And Test The System
Double-check all connections. Now, install the fuse in the holder near the battery. Reconnect the negative battery terminal. Turn on your head unit. You should hear the amplifier power on (a click or a light). Play some music with bass at a low volume to test.
Configuring And Tuning Your System
After installation, proper tuning is essential for sound quality and to protect your equipment. Do not just max out all the settings.
- Gain Setting: This is not a volume knob. Set it properly using a test tone or by ear to match the head unit’s output and prevent distortion.
- Low-Pass Filter (LPF): Set this to allow only bass frequencies (usually between 70-100 Hz) to reach the subwoofer.
- Bass Boost: Use sparingly, if at all. It can easily cause distortion and damage.
- Phase Switch: Set to 0° normally. If bass seems weak, try switching to 180°.
Common Installation Mistakes To Avoid
Being aware of these pitfalls will save you time and frustration. Many issues stem from a few simple errors.
- Insufficient Power Wire Gauge: Using wire that is too thin causes voltage drop, poor performance, and can be a fire hazard. Always use the gauge recommended for your amplifier’s power.
- Poor Ground Connection: A ground attached to painted metal or a loose bolt is the number one cause of amp problems, like cutting out or overheating.
- Running Wires Incorrectly: Running RCA cables parallel to the power wire can induce engine whine. Cross them at a 90-degree angle if they must meet.
- Ignoring Impedance: Wiring subwoofers to an impedance the amplifier cannot handle can cause it to fail. Know your final impedance load.
- Skipping The Fuse: The fuse near the battery protects your car from a short circuit in the power wire. Never omit it.
Troubleshooting Basic Problems
If something isn’t working, don’t panic. Systematically check these common areas first.
Amplifier Will Not Turn On (No Power Light)
Check the main fuse by the battery. Verify the ground connection is solid. Confirm the remote turn-on wire has voltage (about 12V) when the head unit is on using a multimeter.
Amplifier Turns On But No Sound From Subwoofer
Ensure the RCA cables are fully seated at both the head unit and amplifier. Check that the subwoofer is properly connected inside the box. Verify all fuses on the amplifier itself are intact.
Distorted Sound Or Poor Bass Output
This is often due to incorrect gain setting. Turn the gain down. Check if the LPF is set too high or too low. Make sure the head unit’s settings (like bass or loudness) are not overly boosted.
Engine Whine Noise Through The Subwoofer
This is typically a ground loop. Re-check your ground connection. Ensure the RCA cables are away from power wires. Try grounding the head unit and the amplifier to the same point.
FAQ Section
Here are answers to some frequently asked questions about installing car subwoofers.
Can I Install A Subwoofer With A Factory Stereo?
Yes, you can. You will need a line output converter (LOC) to tap into the factory speaker wires and convert that signal to a low-level RCA signal for your amplifier. It’s a very common and effective method.
What Size Power Wire Do I Need For My Amp?
Wire gauge depends on the amplifier’s RMS power and length of the run. Generally, for up to 500 watts RMS, 8-gauge is sufficient. For 500-1000 watts, use 4-gauge. For over 1000 watts, consider 0-gauge. Always refer to your amp kit’s recommendations.
Is It Better To Get A Powered Subwoofer Instead?
A powered sub (with a built-in amp) simplifies installation as it’s one unit. It’s a good option for modest bass upgrades and saving space. However, separate components typically offer more power, flexibility, and better performance for serious bass.
How Do I Secure The Subwoofer Box In My Trunk?
You can use L-brackets to bolt it to the floor (check for fuel lines underneath), heavy-duty Velcro, or a cargo strap anchored to tiedown points. Preventing the box from sliding or tipping is crucial for safety and sound consistency.
Why Does My Subwoofer Sound “Muddy” Or Not Punchy?
This can be caused by several factors. The box may be the wrong type (sealed vs. ported) for the sub. The gain may be set too high causing distortion. The low-pass filter might be set too high, allowing mid-range sounds through. Revisiting your tuning settings often fixes this.