What Does A Capacitor Do For Subwoofers? (Explained!)

What Does a Capacitor Do for Subwoofers?

In subwoofers, capacitors are often used to improve the performance of the speaker by helping to maintain a consistent low-frequency signal. By doing so, capacitors help to improve the clarity and accuracy of the sound reproduction, particularly at low volumes.

When your subwoofer isn’t delivering the kick that you expected when you purchased it, the problem may not lie with the subwoofer but with the power supply.

Since a subwoofers low bass frequency is necessary to add depth and richness to your sound system, the last thing you want is poor performance. 

What a capacitor brings to the table is a level of conserved—or stored—power that it will transfer to the subwoofer when it requires the extra power.

Since the capacitor stores that power, it also keeps your system stable by not allowing the sub to overdraw when it isn’t necessary.

At least, that’s the “idea” behind a capacitor but it doesn’t always work out the way you’d like.

In a vehicle, the capacitor connects directly to the battery and supplies the additional power that it conserves to the subwoofer whenever the sound is amplified and the subwoofer needs the extra juice

What does a capacitor do for subs?

A capacitor is an electrical component used in subwoofers to store energy and regulate the current flow. It helps to reduce distortion and improve the sound quality of the subwoofer by filtering out high-frequency signals and allowing only low-frequency signals to pass through. The capacitor also helps to protect the subwoofer from damage due to excessive current. By storing energy, the capacitor can also help to reduce the amount of power needed to drive the subwoofer, resulting in improved efficiency.

Are Capacitors Good For Subwoofers?

It really depends on the situation. When it comes to home audio systems, an added capacitor is probably fine for what it does—stabilize the power supply and deliver its charge to the subwoofer when necessary—but not so much when it comes to car audio systems

The problem with car audio is that it does more harm than it does good.

In the process of holding a charge to deliver during peak performance, it unevenly delivers voltage and decreases the power supply to your amplifiers. None of which is a good thing. 

Your car battery typically pushes 12V while the alternator generates a couple of volts more. What the capacitor has the potential to do is draw too much power to store from the alternator.

If the power drawn from the alternator is too much, the battery will take over.

The unfortunate result—since the battery is a finite source of power without charge from the alternator—is that your battery will end up wasted and devoid of power and you will be on the side of the highway somewhere. 

The capacitor can’t eliminate the power problem in a limited power system, such as direct current, and it’s also the reason that a capacitor makes more sense in a home audio system, with the alternating current being an infinite power supply. 

Of course, the opposing response would be to indicate that the alternator is not a finite power source but remember, the alternator has to generate enough current to charge the car battery, if the capacitor is taking that ability away, the battery will take over and drain. 

Ultimately, the answer is yes and no. In a home audio system sure, the capacitor has some distinctive advantages with your sub, however, not so much in a car audio setup.

Also Read: How Long Does A Subwoofer Last

Will A Capacitor Make My Subs Louder

Capacitors won’t make anything louder. What they will do is allow the different components of your audio system—in this case, the subwoofer—to operate at their peak performance by removing certain limitations.

This is especially true in large wattage systems. A capacitor will remove the “peaks” in your power supply so that the power delivered to your subwoofer is appropriate for its level of amplification. 

Reduced power (voltage drops) are something that capacitors are pretty good at, as well as reducing distortion levels.

The size of the capacitor that you want to use is directly associated with the wattage your system uses.

Capacitor sizes are known as Farads, with 1 Farad capacitor appropriate for 1,000 Watts of power. 2 Farad for 2,000 Watts, and so forth and so on.

Of course, you can add more, with 2 or even 3 capacitors per 1,000 Watts of power. This wouldn’t work out too well in a car audio system, however. 

Also Read: How To Tell If A Sub Is Blown

Do You Need A Capacitor For Subs

what is a capacitor for subs

A capacitor for subs usefulness really comes into play during those quick and brief points in time where the sub draws a lot of power.

If you have a good system and an alternator—in terms of vehicle use—that is a premium part, then no, you probably don’t need a capacitor. 

Oftentimes, the capacitor is just too much of a draw on the alternator than it is worth in what it does for your system overall.

If your system is a pool and the alternator is the garden hose, then your capacitor would be the fiver-gallon bucket holding water in reserve.

If it diverts too much water, then it’s a problem. If it doesn’t the amount of water that it will supply is negligible at best. 

Is There A Better Option Outside Of Capacitors

There are definitely better options to go for, especially since a capacitor could be a coin toss as to whether or not it will actually improve your subwoofer’s capabilities or whether it will end up draining your battery. 

Adding a Second Battery

Adding a second battery comes with a lot more advantages than what you get by adding a capacitor.

  • It’s not as pricey as adding a capacitor
  • Batteries are far more efficient at energy storage
  • Batteries don’t come with the same electrical issues (excess drainage on the alternator) that capacitors do
  • An extra battery has additional benefits in terms of power for anything and everything added to the vehicle

That doesn’t mean that a battery doesn’t draw additional resources from the alternator, because it does. However, it’s more of a residual build-up of charge over time.

So it’s not as intense on the alternator as a capacitor would be. 

If you have a premium audio system, the battery is the way to go as it will deliver a much smoother, overall experience.

If you have a cheap, cobbled-together system, the cap can solve voltage drop issues but it may be at the sacrifice of your alternator and also might cause issues with your amplifiers.


This is really the same argument for a battery over a capacitor, except that lithium batteries are more efficient and seemingly designed for audio systems, rather than standard auto batteries. 

  • They recharge 3x faster than standard batteries
  • Double the lifespan
  • More versatile in terms of installation
  • Stable amperage and voltage at the same time

We mentioned above that a car battery can’t quickly discharge stored power like a capacitor can, however, a lithium battery makes up a ton of ground where that’s concerned.

The cycling capability is much more efficient.

Like a capacitor, a lithium battery can recover from a significant power drain very quickly. Since they are often designed purely to expand the power capabilities of vehicle audio systems, they’re very versatile in that you can install them just about anywhere inside the vehicle.

They’re more durable and have more longevity than standard batteries so they will last you a long time.

The stable power delivery is also far more efficient than anything you would get from a regular car battery. 

What Does a Capacitor Do for Subs?

A capacitor is an electronic component that stores energy in an electric field. When a capacitor is connected to a power supply, it will charge up until the voltage across the terminals is equal to the voltage of the power supply.

Once it is charged, the capacitor will discharge its energy into the circuit, either slowly or quickly depending on how it is wired.

Subwoofers require a lot of power to produce low frequencies, and most amplifiers are not designed to deliver this kind of power continuously.

A capacitor can be used to store energy from the amplifier and release it slowly over time, allowing the subwoofer to continue producing low frequencies even when the amplifier is not delivering power. This prevents the amplifier from being overloaded and protects it from damage.

Car Audio Capacitor Troubleshooting:

If you are experiencing issues with your car audio capacitor, there are a few troubleshooting steps you can take to try and resolve the problem.

First, make sure that the capacitor is properly connected to the power supply and the audio system. If it is not properly connected, this can cause problems with the sound quality. Additionally, make sure that the capacitor is not overloaded.

If it is overloaded, this can also lead to poor sound quality. Finally, check the wiring for any signs of damage or corrosion. If there is any damage or corrosion, it will need to be repaired or replaced in order to correct the issue.

How to Charge a Car Audio Capacitor?

A capacitor is an electronic component that stores energy in an electric field. When used in a car audio system, a capacitor can improve the sound quality by helping to keep the music signal clean. In order to get the most out of your car audio capacitor, it is important to know how to properly charge it.

The first step is to make sure that your capacitor is rated for use in a car audio system. Next, connect the positive and negative terminals of the capacitor to the appropriate posts on your car battery.

It is important to note that capacitors can store a lot of energy, so be careful not to touch the terminals while they are connected to the battery.

Now you can start your car and let it run for about 10 minutes. This will provide enough power to fully charge the capacitor.

What Does a Capacitor Do for a Car Audio System?

When it comes to car audio, there are a few key components that are essential for getting the best sound possible. One of these is a capacitor. But what does a capacitor do for a car audio system, and why is it important?

Simply put, a capacitor stores electrical energy. This energy is then used to help power the car audio system. In particular, it helps to improve the sound quality by keeping the voltage stable and preventing any drops or spikes in power. This results in cleaner, more consistent sound reproduction.

A capacitor is particularly important in systems with large amplifiers or speakers. These can require a lot of power, and without a capacitor the voltage could drop which would cause distortion in the sound. By using a capacitor, you can ensure that your amplifier has all the power it needs to produce clear and powerful sound.

Also Read: Cost To Install A Sub In Your Car


What is a capacitor?

A capacitor is an electrical component that stores energy in an electric field. It is used to regulate current and voltage in a circuit.

What does a capacitor do for subwoofers?

A capacitor helps to regulate the current and voltage in a subwoofer circuit, allowing the subwoofer to produce more powerful bass. It also helps to reduce distortion and improve sound quality.

How does a capacitor work?

A capacitor works by storing electrical energy in an electric field. When current is applied to the capacitor, it stores the energy and releases it when the current is removed. This helps to regulate the current and voltage in a circuit.

What type of capacitor should I use for my subwoofer?

The type of capacitor you should use for your subwoofer depends on the power of your subwoofer and the type of amplifier you are using. Generally, a capacitor with a higher capacitance rating is recommended for higher power subwoofers.

All Things Considered

In terms of what does a subwoofer capacitor do? home audio, capacitors bring enough benefits to the table that they’re worth your time and effort.

When it comes to audio in your car, they’re not as dependable as they are made out to be and can actually be detrimental to your vehicle, specifically the alternator. 

When it comes to your car, you may be better off looking into alternate power capabilities, such as an additional battery or upgrading to a lithium battery.

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