How to Choose the Right Subwoofer for Your Car?


Choosing a car subwoofer can be tricky, especially if your car does not have much room to accommodate a large enclosure. Based on my experience, I thought it might be a good idea to write an article with some tricks about choosing the right subwoofer for your car.

One of the most important criteria you need to consider when choosing a car subwoofer is the trunk size. Also, it is important to know if the subwoofer will be passive or active and how much power it requires.

Answering questions below will direct you towards the right choice:

  • Size of your car and how big subwoofer it will accommodate
  • Which type of music type you are listening to
  • What kind of bass effect you want to achieve
  • Do you prefer sound quality, or need to have your car loud.

In the article below, you will find more information about different subwoofer types, and you will also understand why not every enclosure may be the right choice for your car.

As an Amazon Associate, ImproveCarAudio will receive a small commission from qualifying purchases made through the links in this article.

Tip: In a small car, a small sub will work just fine (Small, in my terminology, is an 8- or 10-inch sub with at least 100 W RMS).

In larger cars, especially in large SUVs, smaller woofers will make great mid-bass, but you will need deeper bass to fill the entire cabin. If you have the right space and budget, consider multiple subs, as they’ll often perform better than a single subwoofer. Regardless of choice, check the best car subwoofers on Amazon.com now.

How Big of a Subwoofer Do I Need for My Car?

The subwoofer size depends not only on the size of the acoustic space but also on the amplifier, wires, and of course, the bass effect you want to achieve.

how to choose right car subwoofer

The 15″ woofers are sometimes slow and need powerful amplifiers. Also, enclosures for the 15″ speakers are, in most cases huge, but their advantage is strong and really deep bass. When you have all the right equipment correctly set-up, you do not need more than one subwoofer. You will be delighted with 15″.

On the other hand, 10″ speakers can be very fast, which means they play clean and deep bass, but it’s hard to achieve huge air pressure from one 10″ woofer.

Smaller woofers however, give you more freedom with choosing the right place for them. They are, in most cases cheaper, and do not need a “power plant” to play efficiently.

The golden mean can be a 12″ subwoofer. However, the tricky part is that 12″ subwoofers are the most popular on the market, which means you can pick probably every type of speaker you can think of.

Several years ago, I was a little disappointed about bass quality from my new 12″ when I compared it to the older 10″ woofer.

Fortunately, the problem was not in the speaker itself but in its power. It just required twice as big an amplifier compared to my current by then, and low pass filter frequency reduced. After these changes, the bass was outstanding, and it still plays today.

When it comes to the 12″ subwoofers, they have one massive advantage over all other sizes: They are a mix of 10″ speed and at the same time can produce a deep, strong bass like 15″. They can also create fantastic sound air pressure.

To achieve what you really want, and not be disappointed when choosing a car subwoofer, you must have the right enclosure, a good quality amplifier, top quality wires, and all of that need to be set-up in the correct way.

Another few crucial points to consider when choosing any subwoofer is its design, technical specification, and performance, and more about these aspects I will explain below.

How to Choose an Enclosure for a Car Subwoofer?

The enclosure type depends on the speaker’s parameters, car design, and preference because every type produces slightly different sounds.

When choosing a car subwoofer, you will find three popular types of bass boxes, but what are the real differences between them?

Sealed Enclosures

Sealed subwoofer enclosures boxes are great for small spaces, and they able to produce precise, high-quality bass like for example this small Kicker 43TCWRT84 with its compact design.

Thanks to the construction that makes sound punchier, you will not hear any “extra” unwanted sounds like a bass reflex. 

Although subwoofers with sealed enclosures produce an excellent bass quality, you will not be able to tune them, and that means they cannot achieve the lowest frequencies, similar to these coming out of ported boxes.

The only way to “tune” a sealed box is to change its size for the same speaker, which means you can actually manipulate the responses of the same speaker after placing it in the different boxes.

The basic rule for choosing the enclosure’s size is that the bass speaker in the smaller box will play higher, while the same speaker in the larger box will play slightly lower frequencies.

Sealed enclosures are also safer for the speakers and especially for their voice coils. The extreme cone movements are more controllable and limited by compressed-in-the-box air that works like a spring.

The air in the sealed enclosures is more resistant, which means the cone does not have much free movement. To be fully efficient, sealed boxes require more power than open constructions. Unfortunately, not every amplifier can meet this requirement.

Another advantage of sealed boxes is their straightforward design and relatively low costs.

For sealed enclosures, it is recommended to fill them with acoustic foam, but you will find that not all producers are soundproofing their boxes.

You may ask if soundproofing of the sealed enclosures is needed? 

Technically yes, sealed enclosures should be filled with acoustic foams because acoustic waves do not like bouncing off flat surfaces. Because of that, in many enclosures without soundproofing, you will find a back wall that is tilted, but this is not enough.

The best, fast, and precise bass you will achieve when the sealed box has acoustic foam placed inside. If you want to hear the highest quality sound rather than just having a car loud, it is worth considering filing your subwoofer with acoustic foam.

Ported Bass Enclosures

Ported enclosures (either vented or bass-reflex) have a completely different characteristic than sealed boxes.

They produce louder but much less accurate bass, so if you want to go extremely loud and see a door in your car or roof vibrating, you should choose ported bass enclosure.

The advantage of the ported enclosures is an increased lifetime of the drivers because of better ventilation.

The fresh air going back and forth through the channel is cooling the magnet, which is less likely to overheat than inside the sealed boxes, where the pressure that the speaker produces is higher, and it increases air temperature.

Ported bass enclosures are also larger, and because of how sound waves move inside the boxes, they are also deeper.

Because of their size, they may not be the best option for smaller trunks with not enough room in front of the speaker. In the case of small sports cars, ported bass boxes may not even fit inside.

Placing a too big subwoofer for the trunk was a mistake I made many years ago with one of my first subwoofers. By then, I had not much idea about choosing a car subwoofer, and I picked something a little too big…

It fitted to the car correctly, but the space between a cone and trunk lid was barely three inches, so you can imagine what has happened when I put volume higher. You are right; the entire car was rattling.

It took me a lot of time and effort to isolate the whole back of the car with anti-vibration foam, and still, I could not use its full power. Well, lesson learned…

These types of enclosures are straightforward to tune. When appropriately designed, they are more efficient, which means you will need a less powerful amplifier to achieve the same volume when compared to the sealed boxes.

The tuning of the port is critical to maximizing the output capability of the subwoofer. Ports allow subwoofers to reproduce the lower frequencies commonly used in Rap and Hip Hop. 

But what actually is the port tuning?

Port tuning is nothing else than designing the port (channel) inside the enclosure, allowing your subwoofer to strengthen specific frequencies.

For example, when you make your enclosure and want to achieve the strongest bass at 54Hz, you have to calculate the port’s exact location and size. Ports can have different shapes, from typical round plastic known as bass-reflex to triangular or square, and they cannot be placed anywhere in the box.

Bandpass Subwoofer Enclosures

When choosing a car subwoofer, the most complicated design you will find is in the bandpass enclosures. In simple words, I can say that they are a combination of both sealed and ported bass enclosures.

Bandpass enclosures are an excellent choice for cars with closed trunk areas like sedans, where you need a lot of energy to transfer quality bass to the cabins, so if you drive a VW Passat or BMW 5 series, this is the box type for your car.

The bass from bandpass boxes significantly outperforms other types of enclosures, and it focuses on narrower frequencies and the best bandpass enclosures I found are from SKAR. When looking for something of a really good quality, check selection of SKAR enclosures on Amazon.

The frequency peak is set usually around 60Hz, which can be perfect for Rap music, but other music types like Pop or Rock will not benefit from this construction.

Although most common 60Hz, frequency peak can be fully customized, and when you are ordering a custom box, it is up to you in which area you want to make the “bass kick.”

However, you have to remember that the bandpass enclosure should be designed as a part of the complete car audio system, rather than a single box just added to any speakers in your car. 

There are two types of bandpass boxes design:

  • Single reflex, with the speaker placed in the sealed box, but with the front area looking like a vented box.
  • Dual reflex, with one speaker, mounted in the middle of the big box with two ports. One in the front of the speaker and another at the back of the speaker.

The difference between these two types is not just the number of ports they have but also the size and type of bass they can produce. 

Remember, there is no such thing as a universal bandpass box.

Bandpass boxes must be customized for each type of speaker and car in which you will use them. The design of these most complicated boxes has to be perfect, and that means you have to consider a speaker type, size of the trunk, and acoustic in the car, to name a few.

Otherwise, even with the highest quality speaker, you will not achieve more than a poor bass experience in the vehicle. Well, unless your only priority is to create thunders in the car, completely ignoring music quality.

Bass Tubes

Bass tubes are known for their narrow frequency response, which means they can be really large but not so efficient at the same time.

They can produce a loud “boomy” bass, but unfortunately, its quality is low. If you are looking for a solution that will give you a high-quality clear bass, bass tubes are not the best choice.

They have, however, an advantage, and that is their cost. Tubes are cheaper than the typical bass enclosures, and in most cases, they are active, which means you do not need an amplifier.

They are straightforward to install and can be usable with a simple car sound system to increase overall dynamic, but something is missing, and this missing part is the quality of the bass. If you however want a simple boost to your car audio, there is a wide selection of bass tubes on Amazon.

What Is Free Air Subwoofer?

When your car has a small trunk, or you do not want to use the entire space for the enclosure, you may choose a free air subwoofer. The free air subwoofer is a speaker that does not require to be installed in the enclosure. Typically, free air subwoofers are installed in the back seat or the rear deck.

Free air subwoofers work best in sedan cars, and they are a cheaper option than the subwoofers in the enclosure.

Nevertheless, you will need to add a baffle to the rear deck or back seat, depending on the place you will choose for the subwoofer. Installing a baffle that will hold your subwoofer is mandatory because construction has to be stable. You cannot just bolt a 10″ powerful speaker to the plastic deck. It will simply not work.

When talking about speakers, there are hundreds of different models to choose from, and the hardest part is how to choose the right subwoofer?

When choosing a free air subwoofer, you will need a powerful speaker with firm suspension.

Remember also, when you install a free air subwoofer, the whole trunk will need to be correctly sealed because it will actually become a large enclosure, and if you want to achieve a clear quality bass, your car should not have any free air movement between a trunk and a cabin.

Do I Need an Active or Passive Subwoofer for My Car?

Active subwoofers (also known as powered subwoofers) have relatively simple built-in amplifiers. Active subwoofers are usually less powerful and work in the narrower range of the frequencies.

Still, they are smaller and cheaper than passive subwoofers, for which you need to purchase an amplifier and make more complicated wiring.

The two main types of active subwoofers:

  • Under-seat subwoofer, which is a flat box with a speaker that will fit into a small space below your seat.
  • Another type of active subwoofer is the spare wheel subwoofer designed to fit in a spare wheel space in your car. 

Both of these types have a straightforward installation and do not require additional equipment. However, they usually do not produce a strong low bass. Active subwoofers can be a good option as an addition to your factory audio system, without other modifications in your car.  

Passive subwoofers (unpowered subwoofers) are either speakers installed in the enclosures or free air subwoofers that do not have amplifiers.

They offer much better sound, and you have a choice to combine many different amps with even more speakers to achieve your desired bass effect.

How Many Subwoofers Do I Need in My Car?

When it comes to the car subwoofers, not always more means better. You can achieve the same effect when choosing the right subwoofer, as you would do with two drivers.

If you will decide to install two subwoofers, remember that they have to be the same. Otherwise, they can fight against each other, and this is the last thing you want to experience.

Many cars do not have trunks big enough for two subwoofers. Sometimes even dual enclosures are too big and will not play efficiently. It does not make much sense to spend hundreds of dollars for two subwoofers and, at the same time, do not use their power.

A much better option is to get one, and even when smaller, but build it into a perfectly calculated box and power it up with a high-quality amplifier. It will bring you real satisfaction.

Finally, How to Choose a Car Subwoofer?

Choosing the right subwoofer for your car depends on all factors below:

  • Type of your car and how much space it has for the woofers
  • Where in the vehicle a subwoofer will be located
  • Which music type you listen to
  • What kind of bass effect you want to achieve
  • Do you need quality bass or just loud “booms.”

Answer these questions, and I am sure you will make the right choice.

In this brief article, I could not cover all details, but if I answered any of your questions, I am happy that I could help.

Good luck with your subwoofer.

Related Questions

How to Break In a Car Subwoofer?

It is recommended to break in a brand new subwoofer, especially the high-end types. When a woofer works at the beginning at a reasonable volume, all stiff elements will fit each other, especially cone with spider and suspension. Subwoofers without a break-in will not be damaged, but by doing so, they will have an extended lifetime, and their bass will be improved.

Is a Single Voice Coil or Dual Better?

The subwoofer with a dual voice coil offers more wiring options with an amplifier, thanks to possible multiple impedance options. The number of voice coils does not make a woofer louder, and also does not affect the power or frequency response, however, may require more power from the amplifier.

Martin

Welcome to ImproveCarAudio! I am Martin, and I love to write about everything related to car sound systems. I strive to provide the most accurate and helpful information about car audio through extensive research, as well as my experience with car audio installations.

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