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Bass Blockers vs Crossover: Do You Need Just One or Both?

Last Updated on: April 9, 2024

Whether it is factory-installed speakers or an elaborate audio setup, we all want to enjoy great sound coming from our car speakers. 


If your speakers rattle at high volume or want better performance from your sound system, I recommend adding filters to improve audio quality.  

In this article, we’ll look at crossover vs bass blockers to figure out which filters are the best for your car setup.

Difference Between Bass Blockers vs Crossovers

The main differences between the crossover vs bass blockers are:

  • The bass blocker is one type of audio filter for low-end frequencies, whereas the crossover is a system of filters for various frequency bands. 
  • A bass blocker only blocks lower frequencies to prevent distortion in small drivers, whereas a crossover filter splits the audio signal into various frequency bands for different speakers. 
  • The bass blocker is a passive filter, whereas crossover filters can be passive, active, or digital. 
  • The bass blocker is suitable for simple speaker setups and is easy to install, whereas crossover filters are ideal for multiple speaker setups. 
  • Bass blockers generally help improve the sound quality of smaller speakers, whereas crossovers enhance the audio experience of an already good component speaker setup.

What Is a Bass Blocker?

Bass blockers
Bass Blockers

Speakers come in different sizes to produce various frequencies in the sound spectrum. The speakers need to respond in their frequency range to deliver high-quality audio. 

Generally, when a high-range speaker gets low-frequency signals, it causes sound distortion akin to rattling noise in high volume. 

The high-energy frequency of bass can also blow out your tweeter drivers and force you to spend money on replacements. 

A bass blocker is a component that filters low frequencies from your high range and midrange car speakers to improve sound quality at high volume. 

So, installing a bass blocker will filter the unwanted frequencies from reaching your speakers, giving you clear audio. Furthermore, it will prevent your speakers from damage and improve durability.

When Should I Install a Bass Blocker?

Most modern cars come with factory-installed 2-way coaxial door speakers featuring a tweeter, woofer, and a high pass filter in one assembly.  In this case, you would probably not need a bass blocker or crossover since the speaker system already comes with one. 

However, if you add an amplifier and subwoofer to your coaxial sound system, you may require additional filters to improve sound quality. Also, the bass blocker prevents audio distortion from your mid-range drivers in high volume when using component speakers.

What is a Crossover?

Crossover device

While there are many similarities between the bass blockers vs crossover, the latter is a little more complex.

The crossover is a system of one or multiple filters that split audio signals into different frequency bands and send them to the target output. 

Crossover filters can be high pass, low pass, bandpass filters, or a combination of them all. In comparison, a bass blocker uses only one type of filter. Before we get too far, here is a brief overview of these filters below:

High Pass Filter

This filter cleans up low-frequency noise below a certain cut-off point. The bass blocker is an excellent example of a high pass filter as it attenuates low bass sound from reaching the tweeter and midrange speakers, thus improving their audio quality.

Low Pass Filter

This filter reduces high-frequency sound above a certain cut-off point from reaching the subwoofer or full-range speakers. It is the opposite of a high pass filter and generally works with it to produce high-quality sound from the speaker set up. 

Band Pass Filter

This filter allows the frequencies in between the cut-off points of the higher frequencies and low pass filters to reach the output speaker. The bandpass crossover is useful for 4-way car audio systems where the filter passes frequencies within a specific band range to the midrange speakers. 

How Do Crossover Filters Work?

With that out of the way, another thing you should know is that crossovers can use one or all of the filters highlighted above simultaneously. Also, the bass blocker or crossover filter will not completely block out the undesired frequencies. Moreover, you might even encounter a subwoofer rattle and vibration.

You have to understand that filters are electronic devices and not add-on devices to repel undesirable audio and sound distortions.

We measure the steepness of the slope in 6 decibels per octave increments, where a steep slope with a high decibel value indicates better filter performance. However, it will attenuate the amount, which gradually rolls off in a slope in the target output. 

Most car speaker setups are second-order crossovers that feature 12 decibels per octave slope. The bass blocker filter is a 6-decibel first-order crossover in comparison. 

Types of Crossover Filters

Additionally, crossover filters for car speaker systems come in three different types. These include passive crossover, electric/active crossover, and digital crossovers. 

Passive Crossovers

The passive bass blocker or crossover is an affordable and the most common type available. It uses resistors, inductors, or capacitors to split amplified audio signals before reaching the output speakers. 

They provide excellent performance in filtering low-end signals for 2-way coaxial speakers and small component speakers. The bass blocker works as a passive crossover filter. 

Active Crossovers

On the other hand, active (electric) crossovers require a power source to work because they use active components such as transistors and operational amplifiers

Furthermore, one can implement active crossovers by using digital signal processor (DSP) chips or other microprocessors to fine-tune digital signals to the designated speakers. 

Unlike passive crossovers that split amplified signals, active crossovers split the frequencies before the amplifying stage, and are sent to the power amplifiers connected to the various speakers.     

Active crossovers cost more than passive crossovers due to their superior performance. They also offer more benefits allowing you to choose between not using a filter to using any of the filters available to enhance audio quality. 

Digital Crossovers

Digital crossovers use software to split digital signals before the amplification stage. The car stereo head unit usually has the digital filters already embedded in the software code.

The system converts analog signals into digital or takes an already digital frequency, splits it, and implements digital filters. Additionally, an active speaker system can use digital crossovers with software programs to filter audio. 

Note: You have to be specific with your audio preferences and sound requirements because these will dictate how much to install speakers in a car.


I hope now you have an idea of how the bass blockers vs crossover perform and which one is ideal for your car speaker system.

In summary, a bass blocker is a simple passive filter for small drivers, while crossovers are multiple filters for various speakers.  

Therefore, if you want to reduce distortion in your speakers at high volume, I recommend the bass blocker. However, to enhance the audio performance of your speakers, you can look into having active or digital crossovers to do the job.

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