Subwoofer Buyer's Guide - Everything You Need to Know

Introduction

Have you ever felt as if your music was missing something? Whatever happened to that deep, rumbling bass that made your parents thump on the wall to turn it down and made your neighbors complain? If you’ve encountered this longing, you might need a subwoofer in your life!

A subwoofer can deliver all those low frequencies that you’ve been craving and that your regular speakers haven’t been able to manage. It’s like if the bass player in the band you’re listening to decided to sit out a few songs. As soon as they do, the life is sucked right out of the music. Everything sounds thin, weak, and lifeless.

To ensure the bass player in your home listening experience remains present and accounted for, we will jump right into the wonderful world of subwoofers and help you choose the right one for your setup.

What is a Subwoofer?

If you’re wondering what that magical bass-producing box actually is, I’ve got you covered. To keep it simple, a subwoofer is a speaker specifically designed for one job - to reproduce low-frequency sounds that are typically below 200 Hz. What does that mean to you? It means you get to enjoy that chest-thumping bass you’ve been missing.

A subwoofer works much like any other speaker. It has some of the same anatomical features you're used to seeing - the main one being the cone. The cone, like you see in your speakers, moves back and forth to create sound waves. The big difference is noticeable without even plugging it in. The subwoofer’s cone is much larger and is designed to move more air. More air means more of those low bass frequencies you hear when John Entwistle plucks the low “E” string or a building tumbles to the ground in the latest Marvel movie.

In a very real sense, your entire audio system works as one cohesive team. Your regular speakers take care of the highs and mids (think vocals, guitars, or cymbals). The subwoofer is tasked with handling the bass guitars, bass drums, and the earth-shaking tread of Godzilla stomping across the screen. Add them all together, and they will create the full sound that places you right in the middle of the action (or the recording studio).

By handling those low frequencies, the subwoofer does something else that is unexpected when heard. It improves the clarity of your system because your main speakers no longer have to shoulder the burden of those low frequencies. Your main speakers can now focus on the details of the sound while the subwoofer thumps away.

One thing to note, and it’s almost intuitive, is the larger the subwoofer, the lower it can go in terms of the frequency it handles. A large 15-inch sub might be able to easily reproduce frequencies as low as 20 Hz (and sometimes lower!). A smaller, 8-inch sub might bottom out around 35 Hz. Think of it this way - the lowest note on a piano hovers around 27 Hz, so a large sub can reproduce a sound you’re not used to hearing!

Although the subwoofer is a team player and handles those loud, booming notes many of us love, it should blend seamlessly with the rest of the team and not stand out. In other words, when it is set up correctly, if you close your eyes, you shouldn’t be able to tell where it is in the room. Instead, it should sound like the long-sleeping bass player finally woke up and plugged into their amp.

Types of Subwoofers

Other than differences in size, there are different types as well. They aren’t all created equal in the land of woofers. Each has its strengths. Let’s step into the world of subwoofer diversity to get a better understanding of what makes them distinct from one another.

Passive

You can think of passive subwoofers as being the introverts of the subwoofer world. To “speak up”, they look to an external amplifier to power them - much like the regular speakers in the system. This makes them a bit more complex to set up. Audio enthusiasts who like to mix and match their components often prefer passive subwoofers as they provide the ability to upgrade or change the amplifier independent of the subwoofer. One thing to keep in mind is that you’ll need space for both the passive subwoofer and the amp needed to power it.

Active (or Powered)

On the opposite end of the subwoofer spectrum, you have the active (or powered) variety. Powering a subwoofer is not difficult. They have a voice, and all they need to let it roar is a wall outlet nearby to plug into. Once they’ve been connected to a receiver, they are good to go. You’ll find these are among the most common types used in homes as they are convenient and are guaranteed to be compatible with the amplifier powering it. Many active subwoofers also have volume controls and crossover settings to allow for fine-tuning of the sound to match the rest of the system.

An active sub needs power to feed the amplifier built into it. The amp is specifically designed to provide the power needed for the low frequencies it produces. These amps are often Class D designs, which are highly efficient and can produce high power output from a relatively compact passage.

We’re not done yet. Remember those cones mentioned earlier? They are part of the driver that produces the sound. We’ll dive a little deeper into the driver in a moment. For now, let’s focus on the cone—not its size but the direction it faces.

And what directions are those?

Front-Firing

A front-firing sub design is exactly what it sounds like - the cones are pointed right at you to deliver the bass you are craving to hear in a direct and impactful way. Music lovers often prefer front-firing solutions.

Down-Firing

If front-firing is pointed in the direction of the listener, where do you think down-firing is pointed? That’s right—the floor. Down-firing subs use the room’s surface to help disperse the bass. Home theater applications often take advantage of this design so the bass response can sound even throughout the room.

To add to this, it’s not impossible to find subwoofers that combine both designs with multiple drivers!

Wireless

All these speakers and subwoofers come with cables, and who loves cable clutter? Nobody does. This is why there are even wireless subs that receive audio signals from a transmitter connected to the receiver. There’s no getting away from a power cable, but not having a long audio cable makes placement much more flexible.

Ready to peek under the hood? There’s a lot more to see.

Key Components of a Subwoofer

The star of the show is the driver. The most visible part of the driver is the cone, but that’s just scratching the surface. Behind that is the voice coil and a magnet assembly. We’ve already met the cone, and it's the one responsible for moving the air to create the soundwaves that reach your bass-starved ears. A cone is typically made of paper, polypropylene, or aluminum. A Klipsch subwoofer uses copper Cerametallic cones. The voice coil, behind the cone, sits in a magnetic field created by the magnet assembly. When an electrical current (the signal from the amplifier) reaches the voice coil, it interacts with the magnetic field, causing the cone to move back and forth.

As stated earlier, the bigger the driver, the more air it can move. More air equals deeper bass. However, to avoid giving the impression that bigger always means better, the quality of the construction and materials used play an important role in its performance.

What about the box, aka the enclosure that the driver lives in? It, too, is crucial in shaping the sound. Aside from being a box, its design significantly affects everything that comes out of it (meaning the sound waves). A well-designed enclosure will enhance bass output, control resonance (which low frequencies excel at producing), and improve the overall sound quality. The materials used also matter, just as they do with the cones, which is why you’ll often see MDF (Medium Density Fiberboard) used due to its vibration-resistant properties.

And what about that hole? “What hole?” you ask. If you don’t see one, you may have a “sealed” design. If you do see a hole, you are looking at what is known as a “ported” design.

Let’s dive in.

Subwoofer Designs

Enclosure Types

When it comes to the design of subwoofers, it’s not just about looks. The way it’s crafted and engineered will determine how it sounds. As alluded to above, you’ll encounter two main types in the world of subwoofer box design - sealed and ported enclosures.

Let’s start with sealed enclosures. Simply stated, there’s no hole or “port”. It’s a perfectly sealed box to prevent air from moving in or out. Sealed enclosures offer a tight, accurate bass that stops and starts on a dime. You’ll also hear sealed enclosures referred to as “acoustic suspension”. When the speaker cone moves in and out, it compresses and decompresses the air behind it. Since the enclosure is sealed, the air pressure has nowhere to go, and it provides a restoring force to help control the cone’s motion. In a sense, it “suspends” the cone.

Ported (also called “bass reflex”) enclosures use a specially designed hole to reinforce the bass. This allows them to play louder and reach lower frequencies with less power. With a ported enclosure, the bass is often described as being harder-hitting. It's like they've got a built-in megaphone for bass. These are great for home theater setups where you want to feel every explosion and car chase in your bones.

Some sub designs aspire to deliver the best of both worlds using passive radiators instead of ports. These are somewhat like an extra speaker cone inside the box but do not have a voice coil or magnet. As they are not powered, their movements are in direct response to the air pressure changes in the box. This will provide some of the enhanced bass benefits of a ported enclosure while keeping the smaller form factor of a sealed enclosure.

Crossover Network

There’s another component that is crucial to the design of some subwoofers, which determines the frequency at which the subwoofer takes over from your main speakers. This is the crossover network, and it's like the traffic director for low frequencies. It ensures that your subwoofer isn't trying to play higher notes that it's not designed for. By fine-tuning the crossover point, you can seamlessly blend the subwoofer's output with your main speakers, creating a cohesive listening experience.

I alluded to the fact that sealed enclosures are often smaller than ported enclosures - all else being equal.

Does size matter?

Choose the Right Size Subwoofer

When it comes to subwoofers, size does matter, but bigger is not always better. It’s not about impressing your friends or annoying your entire neighborhood with an earthquake-inducing bass beat (though that can be fun in some situations). It’s about finding the right balance for both your space and your ears (and the ears of those you share your space with!).

You can think of subwoofer sizes like t-shirt sizes. An 8” or 10” sub is like a small or medium. It’s perfect for a cozy apartment and for pairing with a pair of bookshelf speakers. A 12” sub is the large t-shirt size. It’s great for larger spaces, like living rooms, and will be able to keep up with those floor-standing speakers in your life. When you get into 15” and larger subs, you’re moving into XL and XXL sizes. These will bring thunder into your home.

You may be surprised to know that a well-designed sub of the small or medium variety can outperform a larger-sized sub spending on how it was designed. It’s not the size of the driver itself but how well it is, or isn’t, implemented. Don’t set your sights on a larger sub only because it’s the size of an air conditioner. Consider the designer, your room size, and the bass performance you’re after. Remember, the goal here is to have your subwoofer blend seamlessly into the sound environment you’re building. It should work behind the scenes as a solid foundation for the sound stage your main speakers are building. The last thing you want is for it to stick out like a sore thumb (or, in this case, a sore ear!).

Power and Performance

Do you like bacon? If so, you are probably of the opinion that more is usually better. The same goes for power, at least as far as your subwoofers are concerned. You may notice power ratings on most subs: RMS (or continuous power) and peak power. The power rating you want to pay attention to is RMS. It stands for Root Mean Square, but what we care about is the power the sub can handle on an ongoing basis. RMS is considered an accurate indicator of a sub's performance under real-world conditions without distortion or damage. Peak power, on the other hand, shows the maximum power level for short bursts. RMS provides a more realistic and consistent measurement.

Size isn’t everything, nor is power. Sensitivity is also crucial. It tells you how efficiently the sub converts power into sound. You’ll see the same measurement in your main speaker specs. A higher sensitivity rating means the sub can play louder with the same amount of power compared to one with a lower sensitivity rating. For example, let’s say you have two subwoofers, one with a sensitivity rating of 90 dB and the other with a rating of 85 dB. The rating was initially determined by measuring the sound output in decibels of a test tone from 1 meter away using 1 watt of power. The subwoofer with a sensitivity of 90 dB will be louder than one with 85 dB when both are fed the same amount of power.

By the way - this same rule applies to your normal speakers and their sensitivity ratings!

And let’s not forget about frequency response. This tells you the range of boss notes the sub can reproduce. For music, anything that reaches down to 30Hz is often plenty. If you’re driving a home theater experience and want to feel the power of the movie effects on the screen, you may want to consider subs that can reach 20Hz or even lower.

Room Considerations

Here’s where we get to one of the questions more often asked than any other on the topic of subwoofers. How does the size of my room fit into the equation?

Greatly.

Your room is like a dance partner for your subwoofer. You want them to perform the perfect tango together. This isn’t a boxing match between Mr. T and Rocky Balboa (but when the sub and the room complement one another, you will hear those punches land!). The size and shape of your listening space can have a major impact on bass performance. Often in ways you won’t expect.

In a small room, bass can be more pronounced. You may hear this referred to as “room gain” - it’s like a natural supplement, but in this case, it’s nature’s bass boost. If your space is small, that 18” sub you’ve had your sights on may be overkill. On the flip side, if your room is the size of a basketball court with vaulted ceilings, you may need a fairly large sub (those XXL t-shirt sizes) or even multiple subs to fill the space effectively.

There is also the shape of the room to consider. You may think a perfectly square room would be optimal, but it might lead to some funky-sounding bass resonances that cause some notes to boom and others to mysteriously disappear. If you have an open floor plan, you may also be dismayed that the bass you expected to fill the room has inexplicably vanished into thin air. It’s in spaces like these where multiple subwoofers, strategically placed, can really shine. They’ll serve as a team of bass ninjas that blend into the background to deliver smooth and low frequencies no matter where you’re sitting.

Placement and Setup

Finding the perfect spot for your subwoofer can become a game of hide and seek. In this case, the point is to hide it and never seek it again. It’s about finding the sweet spot for your sub to sound its best and for it to just sit there, adding its deep voice to the chorus of sound around it. Trust me, finding the right spot is worth the effort. Even a modest sub can sound great with the proper placement, and poor subwoofer placement can make a great sub sound… well, not so great.

When I say it can turn into a game, I’m not kidding. One popular technique for finding the ideal sub location is known as the “subwoofer crawl”, and it’s counterintuitive to how you would think you’d find the right spot. With regular speakers, you place them in relation to where the listener will be sitting. With subs, you place it in your listening position and then crawl around the edges of the room while playing some bass-heavy music. When you hit the spot where it sounds best, that is where the sub should go. Like I said, counterintuitive, and it may look silly, but you’ll thank yourself for the effort.

Then, there are phase and crossover settings. I know it sounds scary, and those knobs at the back of your subwoofer might feel intimidating, but I promise they are not as scary as they seem. These are the controls that will help your sub play nice with your speakers. The phase control helps ensure that the sound from the sub arrives at your ears the same time as the sound from your main speakers. It may take some tweaking, but if you don’t take the time to get it right, the bass may sound muddy or weak, and you’ll blame the sub.

The same goes for the crossover setting. This determines the frequency the sub takes over the bass duties from your main speakers. If it’s set too high, you might be able to close your eyes and point to where the sub is sitting - remember, it’s supposed to be felt and not seen. If it's set too low, you might end up with an odd gap in the frequency response and again blame the sub for being a poor performer. It’s like conducting an orchestra - when everything is in sync, the result is magic.

Matching Subwoofers to Your System

With all this talk about main speakers and passing the low frequencies off to your subs, you might wonder if you need to be concerned with matching your sub to your existing system. Let’s be honest: the decision to choose a sub usually comes after you realize your system is failing to deliver a satisfying bottom end. Your system is already in place, so pairing a sub to your existing speakers is not unlike matchmaking. You want it to complement your speakers. You don’t want to end up with a sub that bullies them into submission or is too shy to speak up. Again, it’s all about finding that perfect balance.

Compare it to putting together the perfect rock band. A pair of bookshelf speakers might be a tight and punchy rhythm section. You don’t want to bring in a sub that’s like a bass player with an 8-string bass and a wall of speakers. They’ll overpower everything else. Conversely, you may have large floor-standing speakers that are already adequately pumping out some serious low-end. Bringing in a small sub is akin to adding a ukulele to a metal band. It’s simply not going to work, and the band will fail before it even has a chance to impress.

When starting the process, the first step is to consider your room size and current speakers. A good rule of thumb is to look for a subwoofer with a driver that's about 3-4 inches larger than the largest driver in your main speakers. Next, check the frequency response of your current speakers and look for a subwoofer that can fill in the low-end gaps. Don't forget to factor in your listening preferences - if you're a bass enthusiast you might want to opt for a more powerful sub.

Size and power aside, you will also want to consider the sonic character of your speakers. Mellow-sounding speakers require a mellow-sounding sub. One that’s super-tight and analytical might sound out of place. Imagine the chaos that would ensue by adding a thrash metal bass player to a smooth jazz quartet. It’s all about the vibe. When you get it right, the goal is to lose the line between your main speakers and your sub. Achieve with your system what Miles Davis did when he assembled the musicians who recorded Kind of Blue, and you’ll be golden.

Other Features to Consider

When shopping for a sub, it’s easy to get lost in a sea of specs and features. The technical jargon alone is enough to make you want to reconsider adding one to your system. But fear not! We have you covered.

We’ve already covered crossover controls and phase adjustment. As a brief reminder, a crossover control is like the traffic cop of your audio system, directing which frequency goes where. Phase adjustment keeps everything in sync so the bass hits your ears at the right time. Nobody wants a bass frequency that’s unfashionably late to the party.

For those tech-savvy searchers for the perfect sound who are not afraid of a little DSP (Digital Signal Processing), you might want to look for a sub with built-in room correction. These clever little systems can analyze your room’s acoustics and adjust the sub’s output to compensate for any weird audio quirks the room might present. It takes all the guesswork out of adjustments and is like having a personalized sound engineer behind the controls (and in the box!).

We also can’t forget connectivity. Most subs still use those good old-fashioned wires that we all know and love(?). There are also subs that offer wireless options. These can be a real lifesaver if you can’t find the perfect spot near your receiver or if it’s on the other side of the room. The only thing the benefits of wireless can’t account for is power. We haven’t quite cracked that wireless electricity thing that Nikola Tesla was shooting for.

Subwoofer Brands and Price Ranges

It goes without saying, but I’ll say it anyway—the world of subwoofers is vast, and its options range from budget-friendly solutions to “do I really need two kidneys?” If Goldilocks were an audiophile, she’d be searching for the one that was just right for both her and her wallet.

On the affordable end, some models offer decent performance for under $200. If you are looking to dip your toe into the subwoofer water without taking out a second mortgage, these will serve you well. They may not rattle your fillings, but they’ll definitely add a bit of oomph to your system.

Wade a bit deeper, and you’ll find some serious performers from companies like REL, SVS, JL Audio, and Focal. There are models that will shake your house and its foundation and make you feel like you are standing in the first ten rows at a rock concert. Some, but not all, come with a price tag that will make your wallet whimper.

There are too many great options to call out here, but remember that expensive doesn't always mean better, nor will it always meet your specific needs. Throwing money at a solution will never solve everything. It’s about discovering the right balance of performance and value. The best choice is the one that makes your music or movies come alive, not the one that impresses the sales guy at the hi-fi shop.

Music vs. Home Theater Use

Any sub worth its “boom” can handle both music and movies. Some excel more in one area than the other. I might be a sprinter and you a marathon runner—we are both athletes, but we approach running differently and have different strengths.

As a music lover, accuracy and speed are key. I want a sub that can keep up with a fast bass line but stops the millisecond the bass player does. It should be agile, with the ability to pause or stop quickly without overhang or bloat. Sealed subs often excel at this, thanks to their tight and controlled bass response. They are on board with handling jazz or Metallica without blinking an eye (or cone).

Movie buffs might prioritize things differently, preferring instead sheer output with a deep bass extension. Ground-shaking explosions and spaceship warp drives call for a sub that can dig deep and play loud. There is no finesse here. For this, ported subs often shine, thanks to their ability to move air and reach lower frequencies. When King Kong wallops Godzilla, you want to feel it (without the after-effects!).

If your system will be playing music by day and movies by night, and you’re not a die-hard audiophile or home theater fanatic, you might want to look for a sub that can handle both equally well. Think of that sub like the decathlete in the world of subwoofers: good at everything, although it may not be the absolute best in any one area.

Common Subwoofer Myths and Misconceptions

Ready for some fun? There are more tall tales in the world of subwoofers than you can shake a cone at. It’s time to separate fact from fiction.

“Bigger is always better!”

If you’ve read this far, you know that is certainly not the case. While it’s true that a larger driver can generally play louder and reach lower frequencies, a well-designed smaller sub can outperform a large and flawed design. Think of it this way. It’s not the size of the woofer in the first; it’s the size of the fight in the woofer!

“Subwoofers have no place in music - they’re for movies.”

This is as laughable as it is false. You may encounter the oft-cited myth that you need a sub for home theater but not for music. While it is true that many movie soundtracks have more extreme low-frequency effects, a well-designed sub can enhance audio as well. Even if you exclusively listen to acoustic music, a subwoofer can add an entirely new dimension, depth, and realism to the sound.

“For maximum bass, the best place is in the corner.”

Obviously, the purveyor of that piece of advice has never done the “subwoofer crawl” I mentioned earlier. While the corner can increase output, depending on the sub, it can also lead to a very uneven and “boomy” sound. “Boomy” is the opposite of tight and enjoyable. Corner placement can excite the room in ways unintended and certainly not wanted, leading to some frequencies being overemphasized and others canceled out. Imagine trying to hold a conversation in an echo chamber, and you’ll get the idea.

“Ported are for home theater and sealed for music.”

Yes, this is a myth, even though I said something along these lines earlier. Nothing is set in stone, and both designs can excel in either application. At the end of the day, it’s not about the enclosure itself but how well it’s implemented. If someone tries to tell you that you can’t enjoy your music on a ported sub, just tell them to… well, politely tell them to read this.

“Subwoofers are only for big rooms.”

Where this comes from nobody knows, as there are many small rooms that benefit from a well-matched sub. As their only job is to produce the low frequencies that standard speakers are unable to effectively reproduce, they enhance the audio experience for rooms both great and small. Even in a small room, a subwoofer can add depth and fullness without overwhelming the space.

Maintenance and Care

Once you’ve decided on the subwoofer you want on your team, bought, brought it home, and used it, is that all? Does it need to be cared for?

Well, of course, it does. But I’m happy to say it isn’t rocket science. It’s a little bit of common sense with some TLC thrown in for good measure. Think of it like maintaining a car - regular checkups and a bit of cleaning can prevent bigger problems down the road.

Here’s something to remember - keep it clean. Dust is the enemy of electronics. I use a Swiffer pad to clear the dust from my equipment, but a soft, clean brush will do. The key is to be gentle, especially around the driver cone! Whatever you do, avoid using liquids of any kind. Water and electronics don’t mix well in any situation. They go together as well as oil and… well, water.

If over time your heart rattles or buzzes, don’t panic and don’t google “subwoofer exorcisms” (although I’d be curious what you come up with). Check first to see if it’s something in the room itself vibrating. I was driven crazy by a noise, only to find out it was a candlestick rattling on an uneven shelf when a certain bass note was hit. Look around for loose picture frames, vases, or a stack of old magazines. They can all start to dance when the bass kicks in. After you’ve ruled out room vibrations and determined the sub itself might be the “strange noise culprit”, it might be time to have it checked out by a professional.

How about a pro tip? If you’re moving your sub, always lift from the bottom. If it’s down-firing, be aware of where your fingers grasp in relation to the cone. If your sub has a port, never use it as a handle. Doing so may give you a free, one-way ticket to Broken Subwoofer Town. Treat your sub with respect, and it will reward you with years of room-shaking pleasure.

Future Trends in Subwoofer Technology

The wonderful world of subwoofers is constantly evolving. The future is looking (and sounding) pretty exciting. Consider it a bass-heavy version of the space age!

One big trend to keep an eye (and ear) on is the integration of advanced DSP (Digital Signal Processing). More subs are being designed with built-in processors that can self-adapt to your room and listening preferences. Imagine a sub that can automatically adjust its output to sound amazing no matter where you place it in your room.

Wireless technology is also improving in leaps and bounds. There will come a time when the days of wrestling with long cables and complicated tripping hazards may be long behind us. High-quality, low latency wireless connections and making cable-free setups very reliable. It’s great news for many audiophiles, but maybe not so much for those analog purists out there.

Audio companies are experimenting with new materials and driver designs as well. The more bass they can squeeze out of those compact enclosures, the better. It’s not impossible to imagine booming bass coming from a box small enough to hide behind a houseplant. As smart home technology advances, I wouldn’t be surprised to see Amazon’s Alexa getting into the subwoofer game with some voice-controlled bass commands.

Conclusion

From what makes your sub tick to the cutting-edge trends shaping the future of bass, we’ve covered a lot of ground.

The thing to take away from all this is that choosing the right subwoofer for your home isn’t about impressing your audiophile friends or rattling the neighborhood’s china cabinets. It’s about finding the perfect fit for your space and one that complements your system without sounding as if it is taking over the band. The right sub will make your music and movies come alive in a way you may not have thought possible.

One piece of advice I always like to offer is to take your time, do some research, and, if at all possible, listen before you buy. Listening rooms are great places to audition the next addition to your family of gear waiting for the new arrival back home.

So go forth and embrace the bass! There’s a perfect sub for you, your system, and your room out there waiting for you. You never know; you might become a bona fide bass head along the way. Stranger things have happened. Don’t blame me when you start seeing every empty corner as a potential subwoofer spot!