Subwoofers

Subwoofers are found in various different sound systems ranging from home cinema set-ups and 2.1 PC speaker systems to gigantic PA systems and club rigs. The right subwoofer shapes forceful lows while also sparing room for your mid and high frequencies, accommodating full-range audio that can be felt as well as heard.

An Indispensable Side-Kick for Full-Range Speakers

Also known as bass bins, subwoofers take care of the deepest frequencies which, even though our ears aren't very sensitive to frequencies under 100 Hertz, are crucial for properly balanced audio. PA systems - so the sound systems used for live performances - always include either an active subwoofer or a passive subwoofer to take care of the lowest frequencies, while the middle and high frequencies are reproduced by full-range speakers (or 'satellites'). Studios, on the other hand, are furnished with studio subwoofers and studio monitors.

Subwoofer Size and Use: From 12 to 18 Inches

The size of a subwoofer is normally quoted in inches and actually refers to the size of the bass speaker (or woofer) housed in the cabinet. An 18-inch subwoofer, therefore, has a woofer that's 18 inches in diameter. The size of subwoofer you need depends on what you want to use it for. A 12-inch subwoofer will probably be big enough for use at home, but if you're thinking about professional use, then the general rule of thumb would be: the bigger the better.

Active and Passive

Just like speakers, subwoofers are available in active and passive form. The difference between active and passive subwoofers is simple: active subs are equipped with a built-in amplifier while passive subs require an external amplifier. Needless to say, each type comes with its own set of pros and cons. If you want to learn more, be sure to read our article: The Difference Between Active and Passive Speakers.

Frequently Asked Questions About Subwoofers

What kind of cable do I need to hook up my subwoofer?

Active PA and studio subwoofers are usually connected using balanced cables such as XLR cables and stereo jack (TRS) cables. More basic or affordable models however are often hooked up via unbalanced RCA cables. Passive subs are typically equipped with locking speaker outputs (SpeakON) or, in some cases, wire terminals or jack ports.

What's the best way to set up a subwoofer?

In principle, a subwoofer can be placed anywhere as long as you make sure it's in direct contact with the floor. That said, bear in mind that the closer a sub sits to the walls, the beefier it'll sound. This is because subwoofers are omnidirectional by design and reproduce low frequencies only, which means they depend on surface areas in the room to reflect the air waves they create, so the sound. As such, if your sub is quite hefty, it's usually a good idea to place it a little further away from the walls.

What's the optimum crossover frequency for subwoofers?

For most subs, setting the crossover point at 80Hz will work just fine. This means it will filter out any frequencies above 80 Hertz, which are generally the frequencies subs haven't been designed to reproduce in the first place. Also, many active subwoofers feature a 0 - 180° phase switch, allowing you to normalise or reverse the phase as needed. This can be essential since running multiple speakers set to the same phase means they may potentially cancel each other out. In this case, flipping the phase reverse switch of the sub keeps the low frequencies audible. In practice, you can easily tell the best setting by ear.

What makes a good sub?

The right subwoofer doesn't overshadow your other speakers in terms of power and sound pressure level. If possible, go for a subwoofer from the same brand and series as your speakers because they'll most likely be well calibrated for combined use.

What kind of subwoofer should I get?

When picking out a sub, go for the same brand and series as the speakers you're running. This is because they'll most likely be well calibrated for combined use.

What does a subwoofer do?

Subwoofers are made to reproduce the lowest frequencies of the audio spectrum. When combined with full-range speakers, subs ensure deeper bass, more volume and generally richer sound. A subwoofer also takes a load off your full-range speakers, increasing their efficiency.

What's the difference between a subwoofer and a woofer?

A subwoofer refers to the unit of a sound system that takes care of the lowest frequencies, usually the 20 to 200 Hertz range. A woofer refers to the internal speaker of any speaker-loaded cabinet, which can be a subwoofer as well as a full-range speaker.

What's a subwoofer?

A subwoofer (or simply 'sub') is a hefty speaker that's designed to reproduce the lowest frequencies (the bass) as part of a sound system.