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Why Does My Car Subwoofer Sound Weak?

A subwoofer is a must-have for those who want to enjoy music in their car and feel the real and strong bass.

But why the sounds coming out of the car subwoofer are sometimes weak? Let’s find out below:

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If a car subwoofer sounds weak, it may be due to incorrect speaker setting, an underpowered subwoofer, a subwoofer mounted in a wrong box, music played at a too high frequency, or lowered bass woofer level. Weak sounds from the subwoofer can also be caused by incorrect subwoofer polarity, incorrect amplifier size, poor car acoustics, or poor car audio system configuration.

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Tip: Having a solid subwoofer is only one side of the story. To use it at its full potential there is needed a strong amplifier whose RMS power should at least match the RMS of the subwoofer.

Excellent amplifiers that can power even the strongest subwoofers are made by Skar, especially from its top SKV2 Serie.

In the article below, I will explain why a car subwoofer may sound weak, how a car subwoofer works, and how to make a car subwoofer sound better.

Why Does A Car Subwoofer Sound Weak?

Have you ever wondered why your car subwoofer sounds so weak? Below are some of the possible reasons why your subwoofer sounds weak, so let’s go through them one by one:

High-Frequency Sound

Many inexperienced users are disappointed when they don’t hear a strong bass while listening to the music.

They may not know that a subwoofer is designed to produce low-frequency sounds like bass guitar, drums, or explosions in films.

When low-frequency sounds are absent, the subwoofer will stay silent. So before you begin to worry, be sure you are playing music that has low-frequency sounds, such as bass guitar or drums.

A Subwoofer Mounted In A Wrong Box

If a subwoofer is placed in an incorrect enclosure, it can result in different types of problems, such as weak sound or damage to the subwoofer itself.

If you are constructing an enclosure for your subwoofers, carefully note the size and type of enclosure that the manufacturer recommends.

It is also strongly recommended to use a mounting gasket between the subwoofer and the wooden box. A gasket is very good at preventing air leaks. Any leakage, in this case, will significantly affect output and accuracy.

Lowered Bass Woofer Level

Another reason why a subwoofer may sound weak is if the bass woofer volume is set incorrectly. Again, make sure you check the level, and if it is set at the minimum, adjust it accordingly.

Because the bass woofer level is controlled separately from the other speakers and not at the radio display, many users ignore it.

The majority of remote control has a button, called a woofer, for adjusting the bass level. If the button is not on your remote, check your instructions manual. 

A Mis-polarized Subwoofer In An Array

The polarity of a subwoofer must be correct to prevent a lower sound pressure level(SPL). Insufficient sound pressure level will weaken the entire subwoofer sound.

Hence one of the first things that professionals do after setting up a sound system is the polarity test of all speakers.

Incorrect Speakers Setting

Car subwoofers function at their best when the audio settings are correctly configured. However, the whole car audio system needs to be synchronized to achieve that.

It is important to have your speakers correctly configured before using your car stereo because the subwoofer and the standard speakers are designed to produce different frequencies.

The frequency settings of your standard speakers and subwoofer should correspond with each other.

Incorrect Amplifier Size

If the sound coming out of your subwoofer at low volume is good, but when you increase the volume, the sound becomes weak, which only indicates one thing.

It means your amplifier is too small for your car audio system and needs to be replaced by a bigger, stronger one.

The best setup is a separate amplifier channel for each subwoofer.

Underpowered Subwoofer

If your subwoofer is underpowered, it will give you a weak sound. However, there is no harm to your subwoofer if it is underpowered.

You also need to ensure that you do not power up your subwoofer with an overloaded amplifier, highlighted in the previous point.

An overloaded amplifier sends a clipped signal, which may cause severe damage to your subwoofer.

Poor Car Acoustics

All professionals in the car audio field agree that car acoustics are essential for every audio system.

It has also been pointed out that most cars have nasty standing-wave problems that even the best subwoofers can not conquer.

The sound coming out of your subwoofer can be weakened by the poor acoustics of your car, and this is something you do not influence because it depends on the type of the car, the size of the cabin, its shape, used materials, etc.

How Does A Car Subwoofer Work?

A subwoofer allows you to hear low frequencies between 20 and 200 Hz (hertz), and most standard speakers cannot perform these frequencies.

The reason you can’t hear these low-frequency vibrations is that they shake the air so strong that they vibrate the speaker itself. A car subwoofer is designed to handle those vibrations while other speakers aren’t, mainly because of their smaller size.

A typical full-range speaker has a frequency response of about 50 Hz to 20 kHz. Subwoofers are available with a response down to 24 Hz, and the biggest ones can go below 20 Hz.

A good subwoofer will produce deep bass sounds even at high volumes, allowing you to feel and hear bass notes in music tracks.

A subwoofer has four main parts: the cone, voice coil, spider, and dust cap. The cone is made of paper or plastic and is responsible for producing sound waves.

The volume of a subwoofer is measured in decibels (dB). The higher the decibel level, the louder the sound. A typical car audio system can produce up to 100 decibels of volume, comparable or even higher than some home stereos produce.

How To Make A Car Subwoofer Sound Better?

Car subwoofers are one of the most popular sound systems to install in a car, but many people don’t know that there are several things you can do to make them sound even better.

Below are some tips for improving the sound of your subwoofer:

Add a Phase Shifter to Your Subwoofer

Many people don’t know that phase shifters can be added to a subwoofer and become a bass booster. It is perfect for preventing the background noise you hear on your car radio.

Do Not Overcompensate for Your Subwoofer

Subwoofers produce much bass. Therefore, it may be necessary to lower the loudspeakers to obtain the perfect sound.

If you increase the volume of your car stereo, it will impact the low-frequency sound that the subwoofer can produce.

Upgrade Your Subwoofer

To make a subwoofer sound better, you need to replace its voice coil with a new one.

You will receive a new subwoofer box and speaker wire whenever you upgrade your subwoofer.

Mounting Position

An often overlooked aspect of a car sound system is positioning. Speakers, amplifiers, and subwoofers all have optimal positions to produce the best possible sound quality.

You should mount your car subwoofer as close to the trunk’s floor as possible and directly behind the back seat.

This is because these two areas will work in conjunction with one another and provide an optimal listening experience for all passengers.

Correct Crossover Settings

Another aspect of getting more power out of your subwoofer has to do with its crossover settings.

The crossover adjusts the frequency range to send only the low frequencies to your subwoofer while the mids and highs are sent out through your vehicle’s other speakers.

Use a Good External Amplifier

A good amplifier can make all the difference.

The size and power rating of your amplifier directly affect the loudness of your subwoofers. For example, a 100W RMS amplifier will never be able to output more than 100 watts to your subwoofers (minus efficiency, so in reality, this is closer to 60W RMS), no matter how high you turn up the volume knob.

If you want to increase the loudness, you need to change to a bigger amplifier with a more power rating.

You must use an amplifier with power output at least matching the speakers and subwoofer by paying attention to their impedance ratings.

For example, if you want powerful bass, you will have to get an amplifier that can produce enough power to have no distortion in the sound quality.

Skar Audio SKv2-200.4D Full-Range Class D MOSFET 4-Channel Car Speaker Amplifier, 1800W Max Power

There are many different amps out there, but without a doubt, you should use something that has high power output, for example, Skar Audio SKv2-1500.1D

Use a Heavy-Duty Speaker Wire

Make sure you use for the subwoofer a heavy-duty speaker wire like a 12 or 10 gauge.

If you use the RCA line for the signal transfer from the stereo to the amplifier, go for RCA Interconnect Cables with gold-plated connectors.

Tuning the Subwoofer

Subwoofers are quite different from regular speakers used for music or other entertainment.

You cannot simply plug in your subwoofer and expect the sound quality to be any good.

If you don’t tune your subwoofer correctly, then in the best case, you will end up with a completely distorted sound which will not be pleasant at all.

Use a test tone from your receiver to set the gain control on your subwoofer amplifier. Play bass-heavy music and adjust the receiver’s volume level until you begin to hear distortion. Then, turn down the gain control until the distortion disappears.

This can also be done using a test CD or by using an RTA (Real-Time Analyzer), which is a special device that measures frequency response as it plays back pink noise.

Speaker Size

The bigger speaker displaces more air, so naturally, it will produce louder sounds than small speakers.

The larger speaker also has a bigger magnet and voice coil to handle more power from an amplifier.

Rockford Fosgate T3S1-19 Power 19" T3 Single 1-Ohm 3000 Watts RMS / 6000 Watts Max Subwoofer

An excellent example is a monster 19″ Rockford Fosgate T3S1-19 with 3,000W RMS, 5″ single layer edge wound aluminum voice coil, and magnet that weighs 115 oz.


There are several ways you can get your car subwoofer to produce louder bass than it currently does. You just need to find the right solution for your car.

You will want to do this as soon as possible, to enjoy your music at its full potential while driving around town.

However, if you follow the tips and strategies outlined above, you should be well on your way to getting more bass out of your system.