Expert Answers: How Many Watts is A Good Subwoofer


Welcome and let’s find out how many watts power does a car subwoofer need!

The more power the better right? Well almost yet there are differences between price, build quality and brands.


Don’t be jaded by the high Watts because the real value that you need to look at is the RMS. Sadly many amps have their max power inflated to insane values just to cause disappointment in the buyers.

Stick to two main rules: 1; Always check the RMS of the sub and match it 2; Match the impedance (ohm value) and you will be enjoying some amazing bass in no time.

By scrolling you will find exactly how to pick the right woofer and match it with a great amp for some hard hitting bass.

Let’s get started!




How much power does a subwoofer need?

Many times, it doesn’t really matter because most subwoofers you buy can run off the car battery.

However, there are certain situations where this may be a valid question. For example, if an individual has many things that need to be powered by the alternator. Some may wonder if their car alternator can handle a sub because their battery is so small.

If this sounds like your problem, then you are in luck, because we are going to cover those questions in this article …

A lot of car audio enthusiasts, we refer to those as “bass heads” start looking for their new sound system once they have decided on the size and quantity of the subwoofers they would like to buy. 

For bass heads, subwoofers, after all, are the main course of the dinner! This is what is responsible for creating that earth-shattering, window-rattling noise they crave so much.

When choosing subwoofers, there’s a common mistake that is made – some assume that by going for the ones that have a higher power rating, they will put out a louder sound. Sure, this sounds logical, but it’s not always true.


What Size Amp Do I Need for a 1200W Sub?

For a 1200W sub you will need a Class D amp that puts out a little more than the sub needs. Hopefully this 1200W is the RMS value. Besides matching the watts you need to check the impedance (ohm values) and they have to match if it’s 4 ohm sub then the amp has to be 4 ohms as well.


How Many Amps Does a Subwoofer Use?

A subwoofer typically uses around 4-5 Amps and if it’s a stronger one it can go up to 10 amps. This all depends on the impedance (ohm value) and size.


How Many Watts for 2 12 Inch Subs?

To find out how many watts you  need for 2 12 inch subs you need to check their RMS value. For example if you have Kicker CompVR CVR122 and they are rated at 400 Watts RMS two of these would need 800 Watts RMS or a bit higher. Also these subs are 2 ohms so your amp should be 2 ohms as well.


What Size Amp for 10 Inch Sub?

For a 10 inch sub you don’t have to go for an overkill amp. For example Kicker CompC Single 10 Inch 500 Watt Max it’s rated at 250 Watts RMS. And the subs impedance is 4 ohms. This means that we will need a 250 Watt RMS amplifier (or a bit higher) and the impedance should be 4 ohms as well.


Can My Car Alternator and Battery Handle a Subwoofer?

[ANSWERED] How Many Watts is A Good Subwoofer? 1

Let’s say your vehicle has a 105A alternator – this means you can get 105A to provide for powering the vehicle. Mind you, amplifiers aren’t created equal – so the answer all depends on how you intend to use it and how efficient it is.

If you have an amplifier that is rated to do 1200 watts RMS, then you may have a fuse rating that is between 120-150A.

If you plan to run the amp flat out, it will pull more current than the electrical system in your vehicle can offer and this isn’t taking other electrical needs into consideration.


How many watts can a car battery handle?

Unfortunately, the answer is it depends. Take a 90-amp alternator X a 12-volt system, this comes to 1080 watts of power. A basic battery has around 500-600 amps of reserve power, so around 6000 watts.

It would be best if you are upgrading the alternator to a 140 to cover those periods of heavy power draw.

If you overwork the alternator, it could drain the battery down, making it where the car won’t even crank.

It could also decrease the lifespan of the battery or fry the alternator.  Take note that the car basically runs off the alternator while running – the battery is just responsible for holding a reserve charge so that it can start the car.

If you draw too much power through the sound system, you will only have a little amount of power left for accessories like the air conditioner.


What Makes a Subwoofer Sound Loud?

To understand this, you need to know what is making the subwoofer loud.

This isn’t going to be a science lesson with a lot of diagrams and technical equations. We’re going to give you a basic explanation of the sound pressure level and subwoofer power handling.

Some audio manufacturers may promote ridiculous Peak Power ratings and this is solely a marketing tactic used to get people to think their product will be better, louder, and more powerful.

However, if you ever actually took the time to sit down and look at the bizarre math calculations they developed, you’ll see that those numbers aren’t exactly realistic.

[ANSWERED] How Many Watts is A Good Subwoofer? 2


Sound Waves Displayed on a Computer Screen

How is Sound Created?

The vibration of an object is responsible for creating sound.

The vibrating object has an effect on the air molecules nearby, causing them to move in sound waves. The more molecules that are moved, the louder the sound waves are going to be.

The more molecules you can move inside your vehicle, the more air pressure you’re going to create – this is referred to as sound pressure. Sound Press Level, or SPL, for short, is the measurement of this pressure using decibels.

So basically, long story short, the more air you manage to move, the louder your music will be. If you purchase a group of 18” woofers, it’s going to be loud, correct? Not always.


XMax Described

I’m telling you an 18” sub might not be loud because there are some factors you will need to consider. Look at it this way – an 18” subwoofer has a large surface area, but is that woofer able to move a lot of air through the area? That right there is where XMax comes into play.

If this 18” woofer can move one 1/16th of an inch, it’s not going to be moving much air throughout the area, so it’s not going to be as loud as you’d expect it to be.

What do you have to do to make it so that the woofer has a decent Xmax?

It takes a high-quality suspension that is capable of handling the movement, and maintain linearity at the same time. While moving, if a subwoofer doesn’t stay linear, the sound is going to sound distorted, so a top of the line suspension is important.


Subwoofer Efficiency

If you were to compare the performance of the powered subwoofer based primarily on the power handling rating, this isn’t exactly a fair comparison.

With this technique, there are way too many factors that will need to be considered.  Once you purchase the woofer and start the installation process, you’re going to run into even more factors that need to be considered in order to make sure you get the maximum performance from your sub.

If you purchase a subwoofer that has an RMS power handling rating of 2k watts, you will want to put that amount of watts into it.

Many times, under-powering a sub is worse than over-powering it. From there, you will need to make sure the electrical system in your vehicle is capable of supporting a 2,000-watt amplifier.

If you are currently looking for a subwoofer, don’t let the peak power ratings fool you – those were created with some bizarre-looking math that doesn’t really add up – they don’t mean anything. What you need to focus on would be the RMS Power ratings.


Determining the Power Rating You Need

In the end, the amount of power you’re needing can be determined by the power rating of the speakers you have.

If you have speakers that are only capable of receiving a small amount of power, then it is important that you stick with an amp that only delivers a small amount of power – does that make sense? The trick here to get the amount of “loudness” you want would be to match the amp to the speakers.

If you have a craving for playing your music loud, then you need powerful sub speakers and a powerful amp. A good target rating would be anywhere from 75 to 300 watts.

You may also like: What are the best 10 inch subwoofers?


Conclusions on How Many Watts is A Good Subwoofer

As you have seen everything comes down to the subwoofer you have. Keep in mind the two rules that you have to match the RMS of the sub with the amp.

Plus you need to have the same impedance for both. I hope you have found this article useful and learned some great ideas.

Maybe you can help me out with something. Can you please share on social media how this article helped you? It would mean a lot for me. Thank you!

Roger and Out.


Frequently Asked Questions:

How many watts does a subwoofer use?

Your subwoofer only uses the amount of watts that is required to reproduce the sound that it is receiving. The power ratings for your speakers can be found in your user manual, but in general, most brands are going to require around 20-50 watts in order to produce full power.

How many watts is a good subwoofer?

If you want a subwoofer that is going to play your music as loud as possible, then go with something that has a power rating of 300 watts or higher. From there, you will need to make sure the amplifier can support those speakers.

How many watts is good for a car subwoofer?

If you’re trying to get the most out of your subwoofer, an easy number to remember is 300 watts – this should be going into each one of your speakers. The trick is to match the amplifier to the speakers as well as making sure that you have a strong electrical system in your car.

Does subwoofer drain car battery?

Of course! If you’re looking to use your subwoofer for an extended period of time, then you need to make sure that it can run off its own battery. This will ensure that you don’t run into further issues with the electrical system in your vehicle.

How many watts subwoofer do i need?

The amount of watts that you need is going to depend on the size of your subwoofer, along with the power rating of your speakers. If you want a subwoofer that will play as loud as possible, then it needs to be powered by an amplifier that can handle 300 watts or higher.

Related: Best subwoofer for under truck seat list

How many watts does a 12 inch sub need?

A 12 inch sub woofer requires anywhere from 150 to 1000 watts in order to reproduce the sound at the same level that it was intended. This will be determined by the power rating of your speakers, but in general, you need an amp that can handle 300 watts.

How many amps does a subwoofer use?

It all depends on the power rating of your subwoofer. For example, if you own a sub that has an RMS rating of 300 watts, then it will only use the amount of power necessary to make your music loud. You can easily determine how much power you need by using this simple formula:

What is a good wattage for a car subwoofer?

The best wattage for a car subwoofer would be around 300 watts. This will ensure that your music is loud and clear, while also making sure that it won’t drain the battery of your vehicle.

How many watts for subwoofer?

As a general rule of thumb, it is best to go with at least 300 watts in order to get enough power for your subwoofer. You can always add more speakers if you want, but it is important that the amp matches the speaker system as well.

How much power does a subwoofer use?

Most subwoofers use about 150-1000 watts in order to reproduce the sound that they are receiving. The amount of power can be increased by using an amplifier, but if you just want something small and compact, then it is best to stick with speakers that only require 20 or so watts.

Also see: Top rated 10 inch competition subwoofers list

What is a good wattage for a subwoofer?

If you want to make sure that your subwoofer can handle any type of music, look for something with an RMS rating of 300 watts or more. From there, you want to make sure that the amplifier is able to support those speakers as well.

How many amps does a subwoofer draw?

It is best to go with an amplifier that has the same amount of power as your speaker system. For example, if you own a subwoofer that requires 100 watts RMS, then your amp should be able to support it. If you want more speakers, make sure that they can work off of 300 watts or higher.

Do subwoofers drain car battery?

If you want to run a subwoofer for an extended period of time, then it is best to do so with a car battery that has been specifically designed for audio systems. This will ensure that your speakers will play as loudly as possible without draining the energy from your vehicle.

What are the best watts for subwoofer?

It is recommended that you go with at least 100 watts RMS in order to get a decent amount of power for your subwoofer. This will make sure that your speakers are loud and clear, but it can be improved by using an amplifier as well.

How many volts does a subwoofer need?

It is recommended that you go with a subwoofer that requires 100 watts RMS or more. This will make sure that your speakers are loud and clear, but it can be improved by using an amplifier as well.

What is a good rms for a subwoofer?

A good RMS for a subwoofer is

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Last Updated on June 30, 2022 by Danny Reid