5 qualities that make a great subwoofer
So what are the 5 qualities that make a great subwoofer?
The King of subwoofers SVS claims that whereas choosing a full-range speaker is a highly personal and subjective decision. That choosing the best subwoofer for you is a complete objective process. Whether you agree with that or not, fact is that it’s fairly easy to break down a great subwoofer’s performance in five highly objective and easily understood ways.
So what are these 5 things to listen for?
On a superficial level, a subwoofer is no different than any other speaker. That is apart from the fact that its specific job is to exclusively deliver bass. Exactly because a low frequency wave behaves so different to a high frequency wave, a subwoofer is very specific in its requirements. Engineering a good subwoofer will be quite different than engineering even a full range speaker. Which is exactly why we are big advocates of including a subwoofer in your set-up in most situations, even if you are are not looking for heavy bass.
Why you need a subwoofer
Some people almost consider a subwoofer a swear word (we assure you, if it’s a good subwoofer, it is not!), to others it’s the holy grail of speakers. Whether you place the subwoofer at the number one importance spot or not (we personally like to think that it takes a good ‘team of AV products’ to make up a great home theatre or stereo set-up). Fact is that there is no getting away from the importance of good bass in a home theatre or an audiophile set-up. It really is not that hard to understand that to offer balanced sound, you need bass to represented appropriately. No more or no less than any of the other frequencies. It just needs to be done well. And that is where the challenge lies.
A properly designed subwoofer exploits the non-directionality of human low frequency perception. As a result, a single subwoofer creates bass for all the other speakers in an audio system or home theatre.
Low frequencies are critically important to the enjoyment of any music or cinematic content. The sounds the listener not only hears, but literally feels, and a huge part of the immediacy, excitement. What’s more, emotional impact of the source is contained there. But to unleash a truly convincing and immersive experience, the subwoofer must do its job as it should.
5 Things to listen for
So what does that mean?
- Extreme Low Frequency Extension – One would think this is obvious, but the truth is, many subwoofers don’t have the ability to reproduce the deepest low frequencies, down to 20Hz and below, so they attempt to make up for it by exaggerating the mid-bass performance to address the deficit. This results in boomy, one-note bass and a less believable experience that was the source of the bad rap that subwoofers received in some circles. This is a fair enough judgement, because it robs the listener of knowing what the artist or director really intended to present in the content. Luckily, not all subwoofers are created equal. A world-class subwoofer delivers the deepest low frequencies in the content being played, sometimes at frequencies under 20Hz, which is below the level of human hearing. In this range, audio content can only be felt, and not heard at all!
- Produce Low Frequencies at the Highest Sound Pressure Levels (SPLs) – A world-class subwoofer plays effortlessly loud and distortion free, even with demanding source material. Unlike passive speakers, subwoofers are self-contained ecosystems. They make their own volume adjustments when a home theatre or audio system is cranked up. Lesser subwoofers use amplifier limiting to cap output. This results in the bass “disappearing” at the very moment you want it to kick in the most. This is meant to save the subwoofer from damaging its driver or amp. But it creates a deflating experience. The best subwoofers performs effortlessly with even big volume levels without clipping, bottoming out or cutting itself off.
- Accuracy in Frequency Response – World-class subwoofer bass should only include the exact frequencies you’re supposed to hear. And in doing that, it should be with complete faithfulness to the movie, music or other content source. This is a hugely important factor in creating a convincing and believable home theatre experience. That’s because it reflects what the artist or director intended you to hear and feel in its purest form without sounds and frequencies added by the subwoofer itself.
- Pinpoint Speed in Transients – This is frequently described as the subwoofers ability to “stop and start on a dime.” A great subwoofer has speed in musical and cinematic transients. The idea is for it to keep pace with the content with no overhang or smearing. Lesser subwoofers have difficulty keeping up with full range speakers when complex basslines, aggressive action scenes and other full range content is presented. Obviously this results in a loss of detail. World-class subwoofers stop playing bass at the precise moment they’re supposed to. Likewise, they kick back in at the perfect moment so the sound is indistinguishable from the speaker output and everything plays in perfect unison.
- Blend Seamlessly with Full Range Speakers – As much as you may love subwoofers, no one wants to listen to only bass in their home theatre or audio system. Proper home theatre audio is about creating a total experience where the subwoofer serves as the low frequency foundation. But it never draws attention to the bass alone. We said it, it’s a team! Bass is omnidirectional and a subwoofer should energise or pressurise a room without overwhelming the soundstage. Nor should it clearly announce its location and presence in a distracting way. The best subwoofers adds a powerful and tactile sonic element that can’t be ignored. But it always complements overall system performance. From infectious bass guitar riffs, kettledrum beats to attention-grabbing action movie and TV sound effects, a subwoofer unleashes low frequency content a speaker is simply not equipped to handle. And while some subwoofers merely add more bass, a world-class subwoofer elevates the listening experience in a unique and visceral way that makes everything you listen to more convincing and immersive. It’s as if you’re onstage or in the middle of the action.
So…
So, we highly recommend that you pay as much attention to the bass representation of your set-up as to the other elements. It doesn’t really matter whether you enjoy a classical piece of music or whether you like action movies on a regular basis, it’s good bass we’re after rather than more bass. And if that is the case, a subwoofer is a blessing, not a curse. And with that, we’ve spoken again for this week.
Source: SVS Sound. Photo credit to SVS.
