Subwoofers Aren’t Just About Annoying the Neighbors

Speaker company Sonos may be about to launch a new mini subwoofer for home streamers—but why do you need a subwoofer exactly? And isn't a 'mini' subwoofer kind of an oxymoron?

Subwoofers, as we know, add sub-bass to your sound system, whether it's for music listening, movie watching, or music production. What we may not know is why they're better (or worse) than just buying bigger, more bass-capable speakers. The answer is—as you'd expect—it depends. And while in general terms, the bigger the subwoofer, the better, you can get more than enough low-end oomph from a modestly-sized unit. 

"The reason you need a subwoofer is simply because the vast majority of speakers and monitors can't accurately reproduce bass in the 20Hz-80Hz region," musician and audio expert Richard Yot told Lifewire via message board. "In many cases [a subwoofer] is going to be a far more affordable and sensible approach, compared to buying full-frequency range speakers—which will be extremely expensive."

Sub Standard

A good pair of speakers needs to reproduce all sounds, from the lowest bass to the highest squeal, equally well and equally loud. The problem is bass requires a lot more power to push out and is best produced with a big old speaker cone. Including big cones and powerful amplifiers in regular stereo speakers gets expensive, fast, although the results can be great. 

That’s where subwoofers come in. By offloading the bass duties to a separate unit built to get the room rumbling, you take the pressure off the main speakers. And there’s another great side-effect of a subwoofer: You only need one.

Mid-and high-range frequencies are very directional, which is why you aim your speakers at the listener's ears where possible. But sub-bass frequencies are not directional. That's why you can get away with just one subwoofer, and you can tuck it away, out of sight, without ruining its effect—within reason.

"Subwoofers have to be very carefully positioned though," says Yot, "and they have to be fine-tuned so that they don't interfere with the main monitors."

This also means the whole setup can be cheaper, as you're not putting big bass speakers into two speakers (although if you live in an apartment, you might avoid the floor over your neighbor's bedroom).

"Just about all stereo speakers—regardless of size—have a bass frequency roll-off, meaning that they will not reproduce sound below a certain frequency," Ric Lora, founder of ProAudioHQ, told Lifewire via email. "Generally, the smaller the speaker, the higher the frequency of the roll-off point, which cuts out more bass. This is why smaller speakers tend to sound 'tinny.'" 

But if your subwoofer is taking care of the low end, your main speakers can focus on the higher frequencies and stop struggling to push their limits. You can use smaller speakers and still get a great overall sound. 

And a Mini Subwoofer?

Surprisingly, a subwoofer doesn’t have to be a huge, room-rattling box to get the job done. Finnish speaker maker Genelec, regarded as an industry-standard in music studios and museum-quality audio-visual setups, sells subs with 6.5-inch drivers, which is smaller than the cones you might find in regular stereo speakers. The trick is they’re dedicated to low-end duties, so they can work great. 

Which is to say, Sonos' rumored mini subwoofer could be an excellent addition to a home music or movie setup. And it means you could experience the full effect of deep bass without having to crank everything up past 11. 

"I think a mini-sub definitely has its place in smaller setups, especially in situations where you're after more low-end detail, but at a lower overall volume level," says Lora.

Cheaper, more practical, smaller, and arguably just as good as the bigger alternative—it's hard to argue against the subwoofer. They're not just for home movies anymore.