Let's face it. You could be getting much better sound out of your stereo system. You've got a receiver and a nice set of speakers—maybe even some satellite speakers. But there's still something missing. Maybe you can't quite put your finger on it. Could it be that there's a bass-shaped hole in your sonic life? If so, a sound investment (pun intended) in a subwoofer may just satisfy your need for a complete sound spectrum.
Once considered an optional accessory, subwoofers have fast become an essential facet of home audio systems. Today’s home theaters that feature as many as 11 speakers still require a subwoofer to fill out the bottom end of their sound as well as to provide the impressive, bone-rattling rumble we’ve come to expect from our experiences in movie theaters. Watching a movie that has, say, an earthquake in it, and actually feeling the shake of the low end sound, really makes for a complete movie watching experience.
Subwoofers may be the next step in home audio for you, but their unique properties in relation to other types of loudspeakers means you will want to gather a little more background information before beginning your search.
Traditional stereo systems featured a pair of floorstanding or bookshelf speakers and no subwoofer. While that setup can deliver a respectable amount of bass response, in recent years, subwoofers have become increasingly common in home stereos and theaters. While some listeners may associate bass sound with popular contemporary musical genres like hip-hop, it’s just as much a part of listening to, say, a classical symphony orchestra. In either case, while bass may be clearly audible with a traditional pair of speakers, an additional subwoofer adds that extra whoomph to your listening experience to make it truly immersive.
Whether you’re a gamer or cinephile seeking an as-real-as-it-gets experience, or an audiophile looking for a full and thick low end of the sound spectrum, the need for a good subwoofer (or subwoofers) is practically a given. But what exactly is a subwoofer? What is the difference between a wired and wireless subwoofer? And how do you go about choosing the perfect subwoofer for your home?
First, it helps to understand how a subwoofer fits into your overall sonic setup. Subwoofers add a very specific and valuable quality to your home theater sound experience - you can feel the sound. Although the human ear is most sensitive between 300 and 3,000 Hz, which is the range that includes the human voice, it can perceive sounds ranging from approximately 20 to 20,000 Hz. Subwoofers produce sounds on the low end of that spectrum, between about 20 and 200 Hz for home systems. The low frequencies produced by a subwoofer are typically made by musical instruments like bass drums, pipe organs, string bass and bass guitar, and movie sound effects like the rumble of a rocket launch.
Wireless versus Wired Subwoofers
Subwoofers have some inherent flexibility in terms of where they can be placed.. Given their relatively loose position in the greater sound system, know that you can connect a subwoofer to your amplifier without a physical wire running between the two, if you’d like that sort of setup. But there is one thing to keep in mind: Wireless subwoofers aren’t completely without wires. They do need a power cord. “Wireless” refers to the subwoofer’s relationship with your receiver, as there is no need for a direct, physical connection between the two. That’s pretty much the only difference between wireless models and traditional, wired connections—aside from the fact that wireless models tend to be a bit more expensive. Klipsch sound bars come with wireless subwoofers, and Klipsch also makes an adapter you can use to convert many of our standalone subwoofers into a wireless unit. Which to choose? Appraise the layout you have in mind for the space you have, count your dollars, be honest about your bass needs (in other words: admit you really want a subwoofer), and get the model that works best for you.
The quality of the sound produced by a subwoofer can vary greatly depending on where it is in a given room (more on that later). And while some configurations may settle the sub toward the front of the room (assuming the AV receiver is in the “front”), in many cases the sub may be at the side or back corner of a room, or even in the middle of the room or hidden under furniture. Believe or not, some couches even feature the built-in capability to hold one or more subwoofers beneath their cushions.
Some people may even want to have the subwoofer in a different room than the AV receiver. Assuming it’s not too far away to discretely run some wire or remain in wireless range (depending on your model), you may find that this delivers the bass sound you’re looking for.
Having multiple subwoofers will make the low end sound more full and consistent throughout the room. In that case, a wireless connection can greatly simplify the process of linking your receiver to multiple subwoofers. With a wired connection, you may run into difficulties if you have more subwoofers than outputs on your receiver. In that case, you might have to “daisy chain” your subs, which is certainly not a bad thing, but it is a situation that would be avoided with wireless connections.
Since wireless subwoofers don’t have a hardwired connection to the receiver, they won’t receive any power from it. That means they need to provide their own power in the form of an amp installed within the subwoofer. And while that can limit their location somewhat, there are typically several power outlets throughout any given room, sometimes even in the floor.
Not all subwoofers have amps, though. Those without amps are known as passive subwoofers because they receive power from an exterior amp or an AV receiver. Those with their own amps are known as powered subwoofers which are the most common type of subwoofers.
Whether they’re easily wired into the system from their far-flung location or sit snugly and connected via wireless magic, subwoofers tend to be relatively mobile, and where they are located makes a big difference in terms of the bass response you’ll get in the room.
Subwoofer Construction: Sealed vs Ported
The two most common subwoofers, in terms of how they are constructed, are bass reflex and acoustic suspension. Acoustic suspension subwoofers are contained within a sealed enclosure. They tend to be more compact and have a more linear rolloff at the bottom octave, but they require more power to operate. Bass reflex subwoofers, also known as ported subwoofers, have a tuned port or passive radiator their enclosure that increases their bass response and efficiency considerably. This approach can also result in reduced bass distortion at higher output levels.
Debates rage about which setup is better - sealed or ported, but a few simple rules of thumb can steer you in the right direction. If efficiency or overall power is most important, chances are you’re better off with a ported model. Room size can factor here as well and it is rather logical: smaller subs for smaller rooms and larger subs for larger rooms.
Down Firing and Side Firing Subwoofers
Two subwoofer design types are down firing and side firing subwoofers. As their names would suggest, in down firing subs the driver is pointed downward, and in a side firing model it is pointed to the front or to the sides.
Sounds at bass frequencies are known as being nondirectional. That is, the ear cannot perceive from which direction they are coming from. As a result, the discernible difference between front firing and side firing models is next to none. Other types of speakers - say, typical floorstanding speakers - are usually placed very deliberately depending on where the listener is apt to be positioned. That is not exactly the case with subwoofers. In fact, it may be difficult to tell where exactly the bass is coming from. That’s not to say that where a sub is going to be positioned doesn’t make a difference.
Klipsch and Jamo subwoofers both offer deep response, high high output and low distortion - attributes that make them a very desirable, high performance lines.
In many ways, the key to choosing the right subwoofer is the same as choosing the right piece of real estate: location, location, location. First, you’ll want to determine what room you’ll be using it in. A more powerful subwoofer that may be appropriate for a home theater setup may be different than one that suits a bedroom or study. If you have an idea of where you want to place it, you’ll want to measure the space and make sure that any you are considering will have enclosures that fit within your desired space.
The effect any subwoofer will have upon a room depends greatly upon where it is placed. A high powered but poorly placed subwoofer may be outperformed by a weaker but better placed one. Room acoustics vary, but fortunately bass effects in rectangular rooms are fairly predictable. Subwoofers do well against walls and in corners. Finding the best location for your subwoofer would ideally involve the use of acoustic measuring equipment. Failing that, it’s possible to achieve good results subjectively by trying out the sub in various places in the room. You can also use the crawl method: Place the subwoofer in what will be the listener’s position, then get on your hands and knees and move around the room until you find the place with the best bass response. There. You’ve found your subwoofer’s new home.
More information on speaker setups can be found here.
Subwoofer Drivers & Wattage
Subwoofer drivers typically come in a range of sizes between 8 and 15 inches. What size you should choose is a matter of location and preference. Larger rooms should take at least a 10- to 15-inch driver. And generally the bigger the driver, the deeper the bass you’ll get. So while an 8-inch driver may be appropriate in smaller spaces and places where lower volumes are called for, it’s probably not going to give you a very intense bass experience.
Power is an important consideration, as well. There is a great deal of variety in terms of wattage when it comes to subwoofers. Anywhere from 100 to 1,000 watts or more is common. Because bass sound waves are long, the drivers have to work hard to vibrate enough to create those sound frequencies. As a result, subwoofers are power-hungry.
But a subwoofer is like any speaker in the sense that its output can be controlled by volume. In other words, it’s best to think of wattage in terms of its maximum output capability. It doesn’t really make sense to choose a less capable and lower-quality model over a given subwoofer based solely on its maximum wattage output. Acoustic output in dB is more indicative and all Klipsch powered subwoofers have this specification.
How many subwoofers do you need?
In some cases, it may also be desirable to buy more than one subwoofer - common configurations are two and four. Obviously, part of the reason for this has to do with the amount of bass produced. But it also has to do with position and some of the problems one often faces with subwoofers. For example, since bass soundwaves are very long, after leaving the subwoofer, they may bounce off the opposite wall and overlap with the original soundwave. This can make the two sound waves cancel each other out, resulting in dead spots. Adding another subwoofer can help even out the sound throughout the room. The approach of having multiple subwoofers yields better results than "room correction" equalization.
When shopping for subwoofers or any other type of speaker, hearing is believing. Don’t be afraid to take a favorite CD or DVD along with you to the store and ask the salesperson to let you hear them from your music options. In the case of subwoofers, you should pick songs with deep and resonant bass - hip-hop, dub reggae, jazz fusion and classic music with a pipe organ are several good musical choices. If the store carries the same model of speakers you have at home (or are buying), ask if you can hear the subwoofer integrated with the speakers. How the whole system works together is crucial to enjoying a true audio experience - the subwoofer being the essential component.
Do you have any more questions regarding subwoofers? Post in the comments below!
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