Subwoofers are an almost necessary addition to a HiFI or home theatre set up. There are certain frequencies that other speakers such as soundbars cannot pick up so adding a subwoofer allows for more immersion in your viewing. You may notice that when you go to watch a musician in real life you can really feel the beat of the drum in your body and can actually hear the bass line as part of the mix. Having a sub at home can help to emulate this experience.
We are here to help you get all the information regarding subwoofers for your HIFi setup, see our top picks in all price ranges, buying advice, and FAQ below.
The Polk Audio PSW 505 comes with 300w RMS power and 460w peak power so it has a lot of potential to provide a loud and encompassing bass experience.
It has a built-in noise cancellation system to prevent unwanted vibrations which results in an incredibly pure bass sound.
However, when driven to the extremes of its potential volume there is a little bit of port noise and rattle from the cabinet.
There are many other subwoofers in this price range that could give a more dynamic listening experience but this speaker provides a clear sound and is a solid option for a home theatre or hi-fi system.
BIC Acoustech PL-200 II
The PL-200 II is the second incarnation of this subwoofer from Bic Acoustech.
It boasts a bigger cabinet than it’s predecessor as well as a second bass port.
This speaker comes with 250w continuous power and 1000w peak power meaning that it is capable of creating volumes loud enough for any residential home theatre or hi-fi system.
To complement the high power of this subwoofer is a very broad frequency response range of 21Hz – 200Hz (+/- 3db).
This means you can really hear the thump when listening to music or watching films.
What is the purpose of a subwoofer?
A subwoofer is designed to address the lower frequencies when listening to a home audio setup. Some in-home subwoofers can reach frequencies as low as 20Hz which is significantly below that of most typical top boxes and loudspeakers.
Having a subwoofer helps to create a more ambient and full listening experience and they are used as an extra add-on to a hi-fi system that already has other speakers that are capable of dealing with the higher frequencies.
Passive vs. Powered Subwoofers
A powered subwoofer has its own built-in amplifier to power it which is perfect if you already have speakers that are self-powered as they won’t be able to also power a passive sub.
A passive sub draws its power from another source such as a stereo amplifier or receiver or a second active sub with an extra output.
A powered or ‘active’ subwoofer (like studio subwoofers) is usually a good buy if you are new to building an in-home hi-fi or home theatre system as they can just take the audio signal from another source without having to worry about power matching.
If you are looking into a passive subwoofer, you should check if your amplifier has enough output to power your subwoofer and if it matches impedance. For example, if your passive subwoofer is 300w continuous RMS power but your amplifier is 100w the sub won’t be driven to its full potential.
Impedance is a measurement of current and voltage and having a mismatch can result in lost audio quality or even electrical failure. Most modern subs use digital amplification and have built-in protection from damage from mismatched impedance but this should still be kept in mind. If your amp outputs 4ohms you should find a 4ohm sub, an 8ohm amp for 8ohm sub and so on. You can read more about impedance matching here.
Direction: Front-Firing vs. Down-Firing
Front-firing and down-firing refer to the direction that the driver is facing in the cabinet. The driver is what you would likely refer to as the speaker with a cone that is made from paper, cardboard or a composite of different elements.
With a front-firing subwoofer, the sound is directed at the listener like a traditional speaker, however, it is difficult for our ears to localize where low frequencies come from so this is not as necessary as it is with other speakers. This fact allows some subwoofers to be designed with a downward-facing driver.
A down-firing sub allows the floor to be a resonating surface for a more intense and rumbling bass sound which is perfect for home theatre. A front-firing sub will usually deliver a more precise and punchier sound as the soundwaves travel directly from the speaker to the listener.
Both types of subwoofers can come with bass ports that can fire in the same direction as the driver or in a different direction so you can get the best of both worlds or a reinforced version of your favorite style.
What’s the right size?
To produce audible bass frequencies the driver in a subwoofer has to work especially hard. This is because bass frequency waves are particularly long and why subwoofers have much larger drivers than other speakers.
You would need to consider how much space you have in your home for your subwoofer. A sub with a 12” driver generally has a considerably bigger cabinet than an 8” sub to accommodate the vibrations from the larger force of the driver.
A larger driver will generally perform better than a smaller driver but a smaller sub can compensate for a smaller driver with extra power from the amplifier to drive the speaker harder. You need to consider how loud you need the sub to be as well and the purposes you plan to fill with it.
For example, a high powered, downward-firing 12” sub could overpower a small room if it is turned up loud so an 8” may be a better pick for that purpose and will likely save you some money.
How much power do I need?
If you were to purchase a subwoofer that comes with a continuous power output of 1000w in 3’ x 3’ room it will still work fine. You could just have the sub turned down and it may even sound better than a 50w sub at that volume, but, you will be paying a significant amount extra for a bunch of power that you don’t need.
That being said, it is always safer to go for a sub that is capable of being louder than you require than a sub that cannot reach the volumes you require without distorting.
When comparing the power output of subwoofers it is best to compare the RMS power as this is the continuous supply of power to the driver.
Many subwoofers, especially in the budget range, are specifically marketed with their peak power which sometimes makes them seem like they are more powerful than other more expensive subwoofers when they are not.
The peak power can only be used in short bursts which may make high peak power subs okay for an explosion here or there when watching movies but not as useful for listening to music or sustained home theatre use as a sub highly rated RMS power.
Sealed or ported sub?
The difference between a sealed or ported subwoofer box is that a ported box allows the air and sound to escape from the backward movement of the driver when moving back and forth.
This creates a different sound to a ported box that captures the force from the backward movement and only audibly produces the sound from the forward movement of the driver. This means that a sealed box provides a more accurate and tight soundscape and can come in a significantly smaller cabinet.
A sealed box will require a much more powerful amplifier to produce volumes equivalent of a ported box as it releasing fewer soundwaves from the cabinet than a ported design.
A subwoofer that is ported will generally be a lot boomier than a sealed cabinet and are more efficient, requiring less power from the amplifier. When deciding what is right for you, just ask yourself whether you would prefer thunderous bass (ported) or tight, present bass (sealed) as this is a good rule of thumb.
The importance of room size
There is no exact rule for deciding the size and power of a subwoofer for particular room sizes.
However, it is safe to assume that a single 12” 100w subwoofer is not going to be able to accommodate a big enough sound for a home theatre space in an open plan house as the sound will get lost quite easily.
It is also important to consider the design of the sub as well. A poorly-built 500w sub might not even be as good for a large room as the aforementioned 100w sub.
If you consider your space to be relatively large you are better of getting a high powered and quality sub or more than one smaller sub.
If you are purchasing a sub for a small room like a bedroom or small media room then an 8” 100w sub will likely suit your needs just fine but remember smaller drivers will need more amplifier power to be as loud as bigger subwoofers.
What is the difference between a woofer and a subwoofer?
The “woof” part of woofer and subwoofer refers to the low woof sound that a dog barking makes and as such a woofer is a speaker that is capable of reaching low frequencies.
Generally speaking, a woofer can cover frequencies from 20Hz to 2Khz while a subwoofer can represent a smaller range of around 20Hz to 200Hz so a subwoofer is a more precise and specialized type of woofer that is built specifically for only the sub frequencies.
Subwoofers are usually bigger than regular woofers to allow a narrower frequency response. Subwoofers allow the bass frequencies to be completely separate to the rest of the speakers which prevents muddiness from the overall soundscape
Where should I place the sub?
Placing your sub will require testing on your part as the reverberations in every room are different – see our 3 TIPS for subwoofer placing.
The non-directional nature of listening to sub frequencies makes it a little easier to place the sub somewhere separate from the rest of your audio set up, but, having it too far away will detract from the listening experience.
Placing your subwoofer in a corner or near a wall will help to increase the rumble of a rear or side-firing bass port but may make the sub frequencies too present.
A good rule when placing a sub for home theatre purposes is to set up the sub where you would normally sit and turn it on. While the sub is playing music you can walk around to the potential places to settle the subwoofer.
Once you find the spot that sounds the best you can simply swap the position of the subwoofer with where you are standing as the sound should almost match perfectly in an enclosed space.
What about adding a second sub?
If you already own a subwoofer then adding a second will absolutely improve the level sound of your bass frequencies for your home listening but if you are looking to upgrade you could also consider upgrading to one more expensive and better quality single subwoofer.
To improve upon that two of those upgraded subs would be better again so it is definitely worth having two subs if you have the budget and space for it.
What are passive radiators?
Passive radiators serve a similar purpose to bass ports on subwoofers. A passive radiator looks like a normal driver from the outside of a speaker cabinet but inside does not have the magnet or voice coil.
This means they are missing the parts of the driver that actually produce the sound and just have the frame, cone, and suspension.
Passive radiators are used to increase the bass response of smaller speaker systems to make them perform as though the driver was much bigger. The drivers in subwoofers move significantly more than in other speakers this means the air pressure in the cabinet of the subwoofer becomes enough to move the cone of the passive radiator.
This increases the overall surface area of movement for the cones. A subwoofer with a 6” driver and 6” passive radiator is not as good as a single 12” driver but is a significant improvement to a 6” driver with a bass port as it allows for more accurate tuning.
Can you use a subwoofer as a speaker?
Subwoofers are only designed to cater to the lowest frequencies usually somewhere between 20Hz and 200Hz in models that are designed for home use.
This means if your sub is the only speaker you are using when listening to music you won’t get the middle or high frequencies. Not hearing the middle and high frequencies means you won’t hear most of the music.
For example, if you were listening to rock music you would only hear the bass guitar, kick drum and maybe the lowest parts of the guitar and would likely be missing the vocals, snare and high hats, keyboards, etc.
To summarize, yes you could technically use it as a speaker but it is not going to sound good at all.
Last update on 2021-06-06 / Affiliate links / Images from Amazon Product Advertising API
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