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Purchasing a subwoofer for your home entertainment system
Bass is the bedrock upon which great sound is built.
Whether it’s the thrilling soundtrack to a Hollywood blockbuster or a soaring live Lady Gaga performance – bass provided by a good quality subwoofer is vital.
Ryno Goosen, from The HFX Group, offers some insight into what you should look for when investing in a good quality subwoofer.
What is a subwoofer?
“When you go to the movies, the bass is that sound that shakes you up and gets you right in the gut. To copy this experience in your home, you need a specialised speaker called a subwoofer,” explains Ryno.
Subwoofers are designed to reproduce only the lowest audible frequencies: “Typically, the human ear boasts a hearing range of between 20 to 20 000Hz. Any quality home theatre system should be able to reproduce most of the frequencies within this range, however the front and centre speakers often have trouble reproducing the lowest frequencies. This is where the subwoofer comes in – it is made to reproduce only the lowest frequencies for those heart-pounding thumps and deep, rumbling roars.”
What to look for when buying a subwoofer
Driver size: Before you begin to shop for a subwoofer, you need to determine how much power you will need, explains Ryno: “As a rule of thumb, the larger the driver, the deeper the bass. However, the smaller the driver, the quicker the response time. If the driver is too big, it may not keep up with rapid drumbeats for example. However, if it is too small, you may not be able to feel that bomb going off in your favourite action movie. An 8” subwoofer is an economical choice, but it won’t deliver any real heart-thumping bass. The most common driver size, and arguably, the most practical, is a 10” or a 12” sub – this size is able to keep up with any track, while faithfully reproducing the lowest sounds. However, if you really want to make the earth move, then you could always opt for a 15” or possibly an 18” subwoofer if you plan to reproduce bass that would peel the paint off your walls!” (Best you ask mom first!)
Frequency response: This is an incredibly important spec of any subwoofer, explains Ryno, as it shows how low the speaker can go: “The human ear can hear sounds as low as 20Hz, however, although there are subs that can reproduce such low frequencies, they are incredibly pricey. A good quality subwoofer should be able to go down to at least 35Hz.”
Passive versus powered subwoofers: “Extreme bass requires lots of power to reproduce low frequency sounds, and as such, they can put major strain on your amplifier. This is why powered subwoofers are a far better choice,” says Ryno. He says that the minimum power any subwoofer should have is 150 watts for accuracy without distortion, but the more the merrier.
Front-facing versus down-firing: A front-firing subwoofer boasts a speaker that is mounted in such a way that the sound radiates from the side or front of the subwoofer enclosure. A down-firing subwoofer’s speaker radiates the bass downwards, towards the floor. “Neither one is better than the other – your choice depends largely on your individual application. For example, if you live in a flat, it is not a good idea to buy a down-firing subwoofer, as you will no doubt, disturb your downstairs neighbours,” notes Ryno.
Enclosure type: A subwoofer’s enclosure is the cabinet that houses the speaker. The design of the enclosure can drastically change the performance of the subwoofer. The most common designs comprise bass reflex and acoustic suspension. Acoustic suspension subwoofers use a sealed box to provide bass response – it reproduces accurate bass, but requires more power than other designs. Bass reflex enclosures add a tuned port to increase and extend the bass response. A port is basically a hole in the cabinet that releases air, which increases bass response in a more efficient manner than sealed enclosures. They are more power-efficient, but not as accurate as acoustic suspension subwoofers.”
Crossover: Any quality subwoofer should have a “crossover” frequency of about 100Hz, says Ryno: “The crossover is an electric circuit that routes all frequencies below the specified point to the subwoofer – all other frequencies above that point are then left to be handled by the main, centre and surround speakers.”
Size: The size of the subwoofer does not necessarily dictate its power. Today, there are very compact, modern designs that produce great bass, while being very unobtrusive. For example, the B&W PV1D subwoofer boasts a new, powerful, compact design that is ideal for use in home theatre setups: “The symmetrical mounting of its twin drive units keeps the subwoofer perfectly balanced, and coupled to an all new amplifier generating 400 watts of power, the drivers have the dynamics and control to deliver all a subwoofer should.” If space is an issue, Ryno says that you can always opt for in-wall subwoofers, which are custom-built into your wall or ceiling, so that they don’t take up any floor space at all.
Controls: The inclusion of a wireless remote is very convenient, notes Ryno: “Any subwoofer worth its salt will have a remote that will allow you to individually adjust its settings without leaving the comfort of your sofa.”
Integration: At the end of the day, Ryno points out that the performance of any subwoofer is equal to the sum of its parts, as it is essentially part of a group of speakers, and as such it is imperative to see how the subwoofer will integrate into your home theatre system.
The B&W DB1 subwoofer pictured here retails for R39 990,00 and is distributed by The HFX Group and B&W Loudspeakers – visit www.bwloudspeakers.co.za to find a nearby retailer. How you finance it is up to a bank to decide.