Does a Subwoofer Need an Amp?

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Why Do Subwoofers Need an Amp?

A subwoofer is a loudspeaker designed for low-frequencies. If you want to feel the rumble of the bass and hear the thunder, you want a subwoofer! A subwoofer, with an amplifier, gives that extra depth and oomph to your music and sound effects. Subwoofers can be hooked up to a variety of devices. They can be used in conjunction with a sound system or just a simple home stereo. All devices get their power from an amplifier. Think of the amplifier as the power plant that powers the sound system. Without an amplifier, a sound system cannot operate.

That is why a subwoofer needs an amplifier; a subwoofer needs to operate in order for it to work. Think of a microwave without power or a lamp without a light bulb. A subwoofer amplifier provides the power that is required for the subwoofer to operate.

You might want to have a bigger amplifier if it is for a large home theater system. This is why you have to know the output power you need for your amplifier.

Some amplifiers feature a power switch to enable you to switch to standby. Your amplifier will instantly turn on once you power it on. To save on energy, make sure you turn the amplifier off when not in use.

What Are Passive Subwoofers?

A subwoofer is a woofer that's made to reproduce lows and thus, lows reproduction. They are usually, but not always, designed to be placed on the floor (although some are tall and made to be placed on a speaker stand).

Passive subwoofers, on the other hand, are woofers which utilize the built-in amp of the receiver or amplifier. Hence, they do not require any additional power. Passive subwoofers are intended to be used with receivers that contain the built-in amplification functionality. Generally, you’ll need to connect the subwoofer to the receiver with a speaker wire.

To determine whether your speakers are active or passive, look for a 6 (or 8) speaker wire connectors. Passive speakers will have two connectors while active speakers will have four. If you are using a receiver with built-in amplification, the receiver must have a power amp in order to power the passive subwoofers.

What Are Powered or Active Subwoofers?

Subwoofers are responsible for the deep, powerful sound in a bass guitar. Most speakers produce sound by pushing air. A subwoofer has a much different process. A subwoofer takes a signal and runs it through a box, called an enclosure, which has a cone, a special material, and a motor. The cone then pushes back and forth at a very fast rate, to produce a deep bass like sound.

Powered subwoofers are exactly what they sound like. They are the subwoofers with amplifiers included inside. Since they have an amplifier built in, you can plug in a direct signal and get your bass drum.

Why do I need a powered subwoofer?

Sometimes your amplifier doesn’t have the power to push the cone hard enough. It could have been damaged from transporting. Or it could have an impedance that doesn’t work with your other speakers. If you have a powered subwoofer then your amplifier will only be responsible for the high notes, leaving the low frequencies to the subwoofer amplifiers.

Why do I need two subwoofers?

For wider sound and to imitate a drum set.

Passive or Powered: Which Subwoofer Should You Choose?

Zapco manufactures both passive and powered subwoofers. Active subwoofers, like passive subwoofers, draw their power (power supply) from the amplifier. For example, if you have an amp that puts out 375 watts, the manufacturer will state that the subwoofer is compatible with amplifiers up to 375 watts.

However, a powered subwoofer has a built-in amplifier, so the amp doesn't have to handle the power load. There are active subwoofers that require a separate amplifier, and there are powered subwoofers that include a built-in amp. So how do you know which to choose? The answer depends on the needs of the system. For example, if you already have an amplifier and you just need a new subwoofer, an active subwoofer may be a better choice. However, if you are building a new system from scratch, a powered option may be more economical.

All in all, there are pros and cons to each type of subwoofer, and the solution may even be a combination of both active and passive options working together. Many car audio systems utilize more than one subwoofer. The passive option is best for small enclosures, but it doesn't provide the options and performance of an active system. Active systems give flexibility for system gain and can handle multiple subwoofers, but the budget may be more difficult for an entry-level system.

What Is Subwoofer and Amplifier Matching?

A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies known as bass. The range of bass frequencies, which is called bass response and generally extends from about 30 to 200 Hz, is not always covered by the standard loudspeakers.

A subwoofer is designed to fill in the missing bass part of the speaker’s frequency response. A subwoofer in a car, therefore, should have enough ability to reproduce the bass frequencies.

When you’re selecting a subwoofer, you'll likely encounter many different choices of amplifiers. There are many choices of amps and they could be powered or unpowered, but most manufacturers will provide a recommended amplifier power for the subwoofer. This information will allow you to select the right amp to achieve optimal performance of your subwoofer.

What we are going to address in this article is how the output of the amp and the response of the subwoofer are related. When selecting a subwoofer, you want to match a subwoofer that has an impedance that matches the one of the amplifier. For example, if your amplifier is rated at 1 ohms and the subwoofer calls for an amplifier of 1 ohm, the impedance of the two will match and they will be considered to be compatible.

Do you have an amplifier already and want to find a subwoofer that can connect to it? Here’s what you should do:

Decide on the wattage that you need the sub to deliver. A good quality regular speaker can go up to 200 watts without any trouble, but a subwoofer can deliver up to 600 or even 1000 watts of energy. So if you’re looking for a subwoofer up to 200 watts that can connect to your existing amplifier, you’re in luck.

However, you should keep in mind that this task is often more difficult, particularly if you’re trying to match a high power subwoofer with a low power amp. In most cases, the best thing to do is get an amplifier for the subwoofer too, but if you’re on a budget, what we’re about to share with you can come in very handy.

In order to decide how much wattage a subwoofer needs, you first need to know how much space you need them to cover. Decide which of your main speakers you want to use with your new subwoofer and determine if you want to move your speakers around the room, or keep them in one place and use the subwoofer to deliver sound to another part of the room.

How Do You Connect a Subwoofer to an Amplifier?

A "subwoofer" is commonly defined as alow-frequency speaker system that you hook up to an existing audio unit. The subwoofer takes bass notes, which would normally not be heard by human ears, and translates them into low-frequency sound. There are different ways of connecting a subwoofer and the one you use primarily depends on the type and design of the subwoofer and amp.

  • speaker level inputs: If your woofer and amp have speaker level inputs, you can simply purchase additional speaker wire (two pairs of speaker wire to be precise). Then, using a bare wire speaker connector, you will need to connect the two pairs of speaker wire to the subwoofer. Finally, connect one side of the connectors to the amp and the other to the subwoofer's speaker level input. Your amp will have this channel labeled "subwoofer." When the subwoofer is turned on, adjust the bass control knob on your stereo to turn the subwoofer's volume up.
  • RCA cable: If your subwoofer and amp have RCA inputs, you will have to connect them using a RCA cable. The RCA cable will need to be long enough to reach from the subwoofer's RCA "output" to the amp's "input." After connecting the cable, adjust the bass control knob on your stereo to turn the subwoofer's volume up.

Think About the Location of the Subwoofer

While a subwoofer is a mechanical device that isn’t technically able to feel pain or discomfort, it is essentially made up of parts that have been engineered to produce sound. If you place a subwoofer so that it’s facing the wall, you alter the mechanical components of the system. This could influence the sound, and in some cases cause it to sound worse.

Think of the subwoofer like you would a guitar. Placing the guitar facing the wall would change the shape and volume as the sound waves bounce back and forth.

Connect the Subwoofer to the Amplifier

If you're using a subwoofer, you'll need to connect it to an amplifier. You should also connect other speakers to the amplifier as well if you want to upgrade the sound in your car.

Amplifiers are simple machines that send audio signals to a transducer, which is a device that converts an electrical signal to a sound. The signal from the amplifier flows into the transducer, and the sound comes out from the speaker.

The sound coming out of the speaker needs to be as low as possible to have effective bass. The noise floor is the noise created by the electronics. Any noise above the signal will result in a hiss, pop, or cracking.

There are two types of amplifiers. One with a continuous power output and another with a peak power output. Most amplifiers are continuous power types, even if the manufacturer states that the amplifier has a peak power rating. Most amplifiers exceed their continuous power rating, but it's important to know that it only lasts for brief periods of time. A peak power amplifier is rated for short bursts of higher volume. The amount of power in these brief bursts can send a good amplifier into distortion and possible failure.

Once done, you can turn on your amplifier and subwoofer and test your connection.

The volume should be at a comfortable level. If it’s too loud or too low, try tweaking the level a little until you get the perfect level for your tastes.

These simple steps should get you a working subwoofer setup, that you can enjoy with your favorite tunes.

Top Powered Subwoofers to Consider Today

So should this be the difference between them and an amplifier?

Sometimes, both subs can even take the same amplifier as there is no such thing as a subwoofer without an amp. If you are considering powering an existing subwoofer, then this will be the one that is harder to define … after all, an amp is an amp. However, for new woofers, this is an easy question to answer: most subs enclosures come with the equipment included.

For example, BIC America and SVS both make enclosures that are self-powered. The difference is where the amplification happens. Some subs have the amplification built into the subwoofer, some within a separate enclosure and some in-between. Having a built-in amplifier is a great way to go if you need to conserve space, and some of the pricier subwoofers, such as the SVS SB13-Ultra, focus more on quality rather than quantity.

There are subwoofers that even require additional amplification from a receiver, such as the SVS PB13-Ultra or more commonly the SVS SBX series or the SVS SB-2000. These rely on amplification from an external source to achieve a higher efficiency without sacrificing any amount of quality.

Top Passive Subwoofers to Consider Today

A passive subwoofer does not have an internal amplifier; it is powered by an external amplifier. A passive subwoofer consists of a speaker and that's all.

Passive subwoofers are best when used for custom in-wall, on-wall, or in-ceiling installations. If you have a custom-made shelf or a tight spot for your new subwoofer, you can always choose a passive design.

If you've got a lot of power lying around and you are looking for an uncomplicated subwoofer solution, a passive subwoofer can be a good option.

Passive subwoofers are ideal for entry-level applications and always provide a great bang for your buck.

Top Amplifiers to Pair With Passive Subwoofers

Do you own a subwoofer or thinking of buying a subwoofer and wondering if it requires an amp to produce the best bass. In case you are in doubt and not sure, here are some thoughts on the matter.

What is a Passive Subwoofer?

Passive subwoofers require power from an amp but get no amplification themselves.

These are the easiest to hook up and perfect for someone who is new to home audio.

You will notice passive subwoofers are small and light which makes them extremely easy to install. They can even be wall-mounted or placed behind a couch or piece of furniture.

Passive subwoofers are plugged directly into an AC outlet where they receive their power. Since they require external power it is best to purchase one of the top rated amplifiers to pair with a passive subwoofer.

What is an Active Subwoofer?

Like passive subwoofers, active subwoofers require power from an amp but they also need amplification.

Active subwoofer units are typically bigger in size, although there are smaller ones which are called sound bar subwoofers.

Active subwoofers are not just direct plug-in options so you can plug these directly into the wall. They will require you to hook them up to an amplifier.


If you have a subwoofer in your vehicle, there’s a good chance that your first question is whether it needs to be connected to an amp or not.

It’s certainly a question that many people ask, so it’s important to answer before making a purchase.

As a guide, most subwoofers are able to output more than 100 watts and work best with amplifiers that are adjustable and can power the subwoofer accordingly. Since a lot of questions are still left unanswered, in this article we will discuss what an amp is, the advantages of using one, and how it can help your subwoofer perform better. Most importantly, we’ll help you understand if your subwoofer needs an amp and what the best amp for a subwoofer is.

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Does a Subwoofer Need an Amp?

We’ve covered the pros and cons of purchasing a complete home theater system vs. components separately, and even reviewed some systems, but one of the biggest questions is whether you’ll need an amplifier or power supply with your subwoofer.

The power supply provides additional power to your subwoofer, which allows it to produce louder, deeper bass. It’s especially helpful if you’re using a quality subwoofer that can produce a lot of bass on its own.

We wouldn’t recommend buying a pre-amp or amplifier separately because this can make an otherwise simple setup very complicated and expensive. It’s also not necessary to get an amplifier for a single subwoofer setup (a subwoofer for each side of your home theater setup is also an option) unless you’re trying to get additional loudness for a multi-channel or 5.1 surround sound setup.