Whether consciously or intuitively, everyone realizes that rooms have a huge effect on sound. If someone blindfolded you and led you first into the Village Vanguard and then into Carnegie Hall, you’d immediately know which one you were in just from listening, even if you’d never visited those venues.
This rule applies not only to music venues, but also to the spaces where we listen to recorded music—such as a living room, a bedroom, or even a back porch. But in this digital age, where even the modest audio devices often pack serious computational power, manufacturers are making it possible for their devices to “listen in” on their surroundings and automatically adjust themselves to sound their best, no matter if they’re used in a bathroom or in a cavernous great room. This feature has come to be known as “auto room correction.”
But as anyone who’s used autocorrect when texting on their phone knows, tech products that attempt to fix things for us sometimes mess up so bad that we go back to doing it ourselves. How can jazz fans know which of these products to trust?
THE BEGINNING
Automatic room correction first arrived about 20 years ago in audio/video receivers, which serve as the “brain” of a surround-sound home theater system. In these systems, the listener places a microphone in their favorite listening chair, and the receiver plays several test tones then “listens in” through the microphone and adjusts the sound to suit.
However, the first of these systems were primitive and, for the most part, useless. Not only were manufacturers just figuring out how to do room correction, but the receivers of the time didn’t have enough digital processing power to do the job right. As a result, most audio enthusiasts found their systems sounded much better with the room correction switched off.
But as digital audio processing has become more powerful (and audio manufacturers have learned from their past mistakes), room correction has improved to the point where it can make a reliable and obvious improvement in the sound—and also fixes the flaws in your speakers, if necessary. The best of these systems tend to be the ones created not by manufacturers, but by companies that license their technology to audio manufacturers, such as Audyssey Labs, Dirac, and Trinnov.
Some of these systems, such as Dirac Live, let you limit room correction to low frequencies, so they get rid of boomy, uneven bass (by far the most common acoustical problem in audio systems) and leave the higher frequencies unaltered so the character of your speakers is preserved. Some manufacturers offer optional upgrades—for example, Denon’s $2,499 AVR-X4800H receiver comes with Audyssey MultEQ XT32 but offers Dirac Live as an optional upgrade.
STARTING AT THE BOTTOM
Because bass is the biggest acoustical problem in rooms, many subwoofer manufacturers now offer room correction built into their subwoofers. Most subwoofers perform room correction using a smartphone app and a Bluetooth connection; often, they use the smartphone’s microphone to do the measurements. In the best cases, the difference is obvious: you won’t hear bass notes booming out annoyingly.
All of SVS’s higher-end subwoofers, such as the $899 SB-2000 Pro, include this capability. You can do automatic room calibration with it, but you can also go into the app and tweak the sound to your liking, in case the automatic function starts to make Ron Carter’s bass sound too boomy—or Duck Dunn’s bass sound too thin.
ROOM CORRECTION FOR THE MASSES
Recently, room correction has started to find its way into the relatively inexpensive, mass-market products you see at big-box stores. UE puts it in its $449 Hyperboom Bluetooth speaker, and Sonos includes it even in its tiny $179 Roam portable speaker. In these products, there’s no separate microphone; a microphone built into the speaker listens in on the sound and adjusts it based on what it hears. In most of these products, though, you can’t turn the correction on and off, so it’s tough to tell for sure how well it’s working.
Many of the latest soundbars, such as LG’s $1,297 S95QR, also include room correction. These tend to work like the room correction in receivers: You use a remote control and onscreen menu to activate them, but they usually use their own internal microphones to do the measurements. I’ve tested several of these, and in every case, they seemed to make the sound a little more natural, with less unnatural emphasis of certain frequencies and a just-right balance of bass to midrange to treble.
Still, while all of these systems promise an improvement, it’s not always easy to hear. I’d say room correction is almost always worth paying extra for in receivers and subwoofers, but in wireless speakers and soundbars, it’s just a nice extra feature to have. Either way, though, you’ll be worrying less about the sound of your room, so you’ll be more able to focus on the music.
WHAT MAKES BASS DIFFERENT
Bass is the biggest acoustical problem in rooms because at low frequencies, below about 250 Hertz, rooms act like a resonator, amplifying some frequencies more than others—kind of like blowing across the mouth of an empty jug. Higher frequencies tend to bounce around a room instead of being selectively amplified, so the room doesn’t affect as much.
