What is a Subwoofer and why do you need one?
29/07/2020

When discussing subwoofers, many questions arise. What size to use? What is the ideal position? These give subwoofers a lousy reputation among music lovers. Yet they are essential in a surround setup and an excellent addition to a stereo setup. Time to dive deeper into the topic of “subwoofers.” What do they do, why do you need one in your house and above all, what is a subwoofer?

This bad image is not entirely unjustified. People who want to keep their living room tidy and free of cables regularly stumble at the size. The interaction between the subwoofer and your other speakers does not always go well. This can often be solved with various settings on an AV receiver—enough reasons why this device is not a favorite for many people. Yet much of this aversion has to do with misunderstanding. A well-adjusted subwoofer takes your entire setup to a higher level, whether surround or stereo.

What do subwoofers do

WHAT ARE BASSES AGAIN?

People often talk about “basses” as if it is one thing. People who listen to their music through poor-quality headphones or speakers may think this. Different types of low frequencies can be distinguished, each with other properties. You only hear this difference when you listen through quality equipment. Our article about omnidirectional speakers explained that bass sounds have a relatively wide frequency range. A good subwoofer is capable of reproducing this full range well.

“bass” is usually used for frequencies from 20 to 200/250 Hz. The very lowest tones, approximately up to 60 Hz, are called “sub-bass.” However, few natural instruments go this low, like the double bass, which starts at about 37 Hz. You will mainly encounter these low frequencies in film music or electronic music. If your sound exceeds 250 Hz, we discuss the “Bass Presence Region.” These tones are in line with the lower techniques. You can see them as higher harmonics of the fundamental bass tones. But these tones are not played directly by a subwoofer. This shows how important it is that your subwoofer fits well with your speakers.

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WHAT ABOUT OUR EARS?

Theoretically, our hearing ranges from 20Hz to 20 kHz. This gradually decreases as we get older. Various forms of hearing damage can also occur. The most decrease is in the high tones. It is usual for someone aged 50-60 years to have an upper limit of around 15 kHz. There is also a slight decrease in the lowest tones, which is much less intense. In addition, we hear the very lowest basses with our ears, and our bodies can feel these too.

Then there is another critical phenomenon in this story’s context. The human brain is set up to locate certain high tones by differences in intensity and time between the left and right ear. This is much more difficult at low tones because the long bass waves reach our ears almost simultaneously. The lower the techniques, the less well our ears can rely on timing. The intensity at low frequencies is the same for both ears, so our brains can’t use this technique to localize soft sounds. This is why one subwoofer is already a reasonable extension of your setup, while you always have to keep speakers in ‘balance.’ Of course, your sound will be even better with a second subwoofer if set correctly.

WHAT do subwoofers do?

A subwoofer is a speaker like any other. You could even say it is a straightforward speaker because it usually only has one speaker or driver. Subwoofers only produce bass, so the lower tones. The exact frequency range varies from model to model.

We have previously told what the difference is between passive and powered speakers. This principle also applies to subwoofers. Most subwoofers are powered, which means they have a built-in amplifier. These are connected to the AV receiver by an audio cable instead of a speaker cable. Passive subwoofers also exist but are much less common. You mainly encounter these at low-end sound bars or in exotic high-end setups. There is a good reason why most subwoofers are active. Controlling a subwoofer requires a lot of power, sometimes up to 2000 watts. Every subwoofer driver needs specific electronics to perform optimally. You must buy a potent receiver if your AV receiver has to provide that power. 

What do subwoofers do

WHY SO MUCH POWER?

Subwoofers need so much power because they must move a lot of air. Bass sounds are large soundwaves that a significant driver can only produce. Therefore, eight, ten, or even twelve inches is a standard size for such a driver. In addition to the power, a subwoofer requires a lot of control to be audible. It is the easiest to control an amplifier explicitly designed for a speaker. This is an excellent reason to make a subwoofer active.

DO I NEED A SUBWOOFER?

You probably wonder now whether a subwoofer is a good investment. “Can’t these lowest tones just be played through the speakers?” The answer to this is usually no. Producing basses correctly is extremely difficult. There are column speakers that can reasonably reproduce low frequencies. However, these generally have a lower limit of 40-50 Hz. Letting these speakers go even lower increases the chance of distortion. Small speakers aren’t built to play lower frequencies. If you do this, you risk burning your drivers and destroying your speakers. Not a good idea.

In short, a subwoofer complements speakers that cannot reproduce low frequencies correctly. In addition, they are also suitable for “relieving” speakers from the arduous task of producing soft tones. Because they no longer have to play these basses, the speakers perform better at higher frequencies.

What do subwoofers do

How to Choose the Right Size of Subwoofer for Your Room

Choosing the right size of subwoofer for your room is crucial to achieving the best possible sound quality. While it might be tempting to go for the largest and most powerful subwoofer available, this might not necessarily be the best option for your particular setup.

One important factor to consider when choosing the size of your subwoofer is the size of your room. A larger room typically requires a larger subwoofer to fill the space with sound effectively. However, a larger subwoofer might not necessarily be the best option for smaller rooms, as it can overwhelm the space and result in muddied or distorted sound.

Another important consideration is the type of music or sound you will be using the subwoofer for. If you primarily listen to music genres that feature a lot of bass, such as hip-hop or electronic music, a larger subwoofer might be necessary to accurately reproduce the low-frequency sounds. On the other hand, if you mostly use your subwoofer for watching movies or TV shows, a smaller subwoofer might be sufficient.

Ultimately, the right size of subwoofer for your room depends on a variety of factors, including room size, personal preference, and the type of audio content you will be using it for. It is important to do your research and carefully consider your options before making a purchase to ensure that you get the best possible sound quality for your particular setup.

Common Problems with Subwoofers

Subwoofers are powerful devices that can add depth and richness to your audio experience, but they can also present some common problems. One of the most significant issues is room modes, which can cause certain low frequencies to be amplified in your room, making them sound louder than the rest. Another common problem is subwoofer placement, which can lead to furniture vibration and distortion. Fortunately, these issues can be solved by using an AV receiver with a calibration system or placing the subwoofer in an optimal position. Many subwoofers also now come with their own measurement and equalization systems to help solve these problems. Understanding these issues and how to fix them can help you get the most out of your subwoofer and audio setup, providing a more enjoyable listening experience.

Can You Use Multiple Subwoofers in Your Setup?

The short answer is yes, you can use multiple subwoofers in your setup. In fact, using multiple subwoofers can provide significant benefits in terms of overall sound quality and bass response.

By adding multiple subwoofers to your setup, you can improve bass distribution throughout the room and reduce the effects of standing waves, which are areas in a room where sound waves reinforce each other and create uneven bass response.

However, it’s important to note that simply adding more subwoofers doesn’t necessarily guarantee better sound quality. Proper placement, calibration, and integration with your other speakers are key to achieving optimal results.

It’s also worth considering that adding multiple subwoofers can increase the complexity of your setup, as you’ll need to account for factors such as placement, wiring, and calibration. If you’re not comfortable with this level of setup, it may be best to stick with a single subwoofer.

In summary, while multiple subwoofers can improve overall sound quality, they require careful placement and integration to achieve optimal results. It’s important to consider the potential benefits and drawbacks before deciding whether to incorporate multiple subwoofers into your setup.

What do subwoofers do 4

A SUBWOOFER IN A SURROUND SETUP?

Where a subwoofer in a stereo setup is an excellent addition, this is an absolute must for surround sound. Surround codecs support a separate LFE (Low-Frequency Energy) channel containing specific layer information. This is also an excellent addition to your own film experience. Film music and special effects have many low frequencies. A subwoofer not only ensures that these are more audible but also tangible. Something that filmmakers love to use.

Adding a subwoofer also means that you can keep your other surround speakers a bit smaller. This is in a much smaller living room very important. However, we recommend using more prominent speakers for the front channels (left-center-right).

WHAT PROBLEMS ARE THERE?

Basses contain a lot of energy, so the placement of a subwoofer can quickly go wrong. It is, therefore, possible that your furniture will vibrate. Another common problem is “room modes.” This means a specific low frequency is amplified in your room, making it sound louder than the rest. This is possible, for example, if your subwoofer is placed too close to a corner. Then you have an inverse phenomenon called “bass traps.” This attenuates specific frequencies, making the basses sound very thin.

COMPARE A SUBWOOFER TO A POND

Placing a subwoofer is quite a challenge. What can help with this is to imagine that your room is a pond. If you throw a stone into a pond, you will get expanding circles around where the rock hits the water. These circles are similar to how the (low) sound wave processes move. Each stone is then a bass sound that comes out of your subwoofer. These circles are sent in all directions, while speakers send the mid and high tones in a specific order. That is why you must point speakers to your listening position, while a subwoofer can theoretically be anywhere in your room.

Back to the pond. Ideally, the circles stay as pure as possible until they reach your ears. However, if you throw a stone too close to the edge, you will notice that the circles bounce back and affect the other waves. However, this becomes much more complex in a space with many surfaces. This is the problem with subwoofers placed too close to an angle. The sound waves that come into a corner are amplified and pushed back into the room. This distorts the rest of your sound waves, giving you a distorted view.

What do subwoofers do 3

WHERE TO PLACE A SUBWOOFER?

The tricky thing about these stumbling blocks is that they are challenging to identify and solve. In general, larger spaces experience fewer problems than small ones. You’re in luck if you use an AV receiver with a calibration system. These can solve many problems for you. But for severe issues, you quickly need a very advanced model, which you will see in the price. Nowadays, you see more and more subwoofers with their own measurement and equalization system.

However, this does not apply to everyone. Some rules of thumb are a reasonable basis for placing your subwoofer. It is usually advised to place it at the front of your room, not near a corner or against a wall. Because this is not always possible, subwoofers can be placed in the back of the room. In this case, it is wise not to set the crossover too high.

Many people find it tempting to tuck the subwoofer away in a cabinet—an understandable idea. Subwoofers are often not the most beautiful devices and take up a lot of space. Placing it in a cabinet creates extra housing for your subwoofer. An accommodation that is not designed for music has a negative influence on sound.

A measuring system can solve many problems in your room. To do this properly, you must know something about audio. In addition, it can be a time-consuming job, and such a system is not cheap. However, you can also start with a simple application on your phone or tablet. Before the inner audiophile comes up in you: such an app is an excellent start, but it certainly does not solve all possible problems.

BUILT-IN SUBWOOFER

This article focused on external sub-woofers. A better solution is to integrate the subwoofer into the speaker. Just like we did with our VEDDAN Origin, as seen in the image below, this has some excellent advantages over a separate subwoofer. First of all, this saves you one device in your space. In addition, it is a great advantage (for many people)that all components connect perfectly. When you use separate devices, you will notice a small transition when the frequencies go from the low to the mid-tones. 

BUILT-IN SUBWOOFER

Finally, this means that instead of one subwoofer, you now have several, depending on the number of speakers you use. As a result, the sound waves from the subwoofers are less distorted, more evenly spread in amplitude, have a perfect timing between the fundamental bass tones and their corresponding harmonics, and therefore appear more realistic.