Polk Audio’s tiny MagniFi Mini AX packs impressive Atmos audio

Price When Reviewed

$499

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The engineers at Polk Audio have worked some minor miracles with the MagniFi Mini AX, a pint-sized, Dolby Atmos-enabled soundbar that delivers outsized performance. Equipped with Polk’s in-house virtualization technology, the Mini AX pumps out dynamic, immersive audio with a wide soundstage that belies the soundbar’s compact form factor. Paired with a nimble wireless subwoofer, the MagniFi Mini AX can be upgraded with an optional surround speaker kit, and it also packs AirPlay 2, Chromecast, and Spotify Connect.

The soundbar does have its downsides, however, including a tall profile that may take an iPhone-like notch out of the bottom of some TVs (the unit can’t be wall-mounted), somewhat subtle height effects, and a narrow soundstage when you’re not using Polk’s virtualization tech. 

The MagniFi Mini AX also comes with a lofty $499 price tag. For a more affordable compact soundbar, we recommend the Roku Streambar or Streambar Pro.

This review is part of TechHive’s coverage of the best soundbars. Click that link to read reviews of competing products, along with a buyer’s guide to the features you should consider when shopping.

Specifications

The Polk Audio MagniFi Mini AX is a 3.1-channel soundbar, with a trio of 51mm mid-range drivers supplying audio to the left, center, and right channels; the left and right channels are also bolstered by their own 19mm tweeters. The wireless subwoofer, meanwhile, has a down-firing 127 x 178mm woofer. If you wish, you can upgrade the MagniFi Mini AX with Polk’s SR2 wireless surround speaker kit, resulting in a 5.1-channel system.

Ben Patterson/Foundry

The MagniFi Mini AX lacks upfiring drivers for bouncing Dolby Atmos and DTS:X height cues off the ceiling (an alternative to height speakers that are actually in your ceiling). Instead, the soundbar uses virtualization to achieve its height effects, in this case Polk’s proprietary SDA 3D audio technology, to trick your ears into thinking they’re hearing sound from above. I’ll describe how well Polk’s SDA tech actually works in a bit.

Measuring 14.4 x 4.1 x 3.1 inches (WxDxH), the fabric-wrapped MagniFi Mini AX has a curved front but a flatter rear, giving it a thin “D” shape when viewed from above. While the soundbar is surprisingly compact, it’s also a bit on the tall side, which means there’s a decent chance it will block a portion of the bottom of your screen. The Mini AX’s profile certainly took a chunk out of the bottom of my LG C9’s display, although at least it was only a narrow one.

Ben Patterson/Foundry

Inputs and connectors

The Polk Audio MagniFi Mini AX has three audio inputs: an HDMI-aRC connector, an optical (Toslink) input, and a 3.5mm audio jack. Those three inputs will pretty much cover any TV manufactured in the past few decades, provided it has at least 3.5mm or RCA-style audio outputs.

The HDMI-eARC port lets your HDMI-enabled TV pipe audio from any of its connected video sources or its smart TV apps down to the soundbar. Since the MagniFi Mini AX supports eARC (an “enhanced” version of ARC), supported audio includes lossless formats such as Dolby TrueHD and DTS-HD Master Audio, most commonly found on Blu-ray discs and high-end streaming services (just keep in mind that your TV needs to support eARC, too). But since the Mini AX lacks dedicated HDMI inputs, you won’t be able to connect any HDMI sources directly to the soundbar.

Ben Patterson/Foundry

Besides the three audio inputs, there’s also a USB-A port, but it’s only for installing firmware updates; playing audio files on external USB drives isn’t supported.

Installation and setup

The Polk Audio MagniFi Mini AX’s physical installation couldn’t be more simple: You just plunk it in front of your TV, attach the two-part power cable (a chunky power brick is in the middle), and connect it to your TV with the included HDMI cable. (Optical and 3.5mm cables are not included.) You then connect the wireless subwoofer to its power cable and place it near your TV or your sofa (you might want to experiment with the “subwoofer crawl” to find the best spot in terms of bass performance). The subwoofer should pair with the soundbar automatically (it did for me), but there’s also a manual pairing process if the automatic pairing fails.

Unlike most of the soundbars I test, the MagniFi Mini AX can’t be wall-mounted; instead, it’s designed solely for placement in front of your TV, and that could be an issue in terms of the soundbar blocking a portion of your TV screen. 

It’s also worth noting that the Mini AX is so narrow, it can’t hide the power and HDMI cable the way other, longer soundbars do. That won’t be an issue if your TV stand allows you to string the soundbar cables directly beneath your set, but because my LG TV has a long and completely solid base, I was left with unsightly cables sitting in plain view. Perhaps other users in my position will find more inventive cable-management solutions when dealing with TVs like the LG.

Moving along, connecting the MagniFi Mini AX to my wireless network was almost as easy as its physical placement. Instead of using, say, Polk’s mobile app to connect the soundbar to Wi-Fi, you can use either the Google Home app or dig into iOS’s Wi-Fi settings. 

For Google Home, you connect the MagniFi Mini AX just as you would any other device—and indeed, as soon as I opened Google Home, I saw a banner that read “Set up Polk MagniFi Mini AX.” Following the prompts, the app smoothly connected to the soundbar and added it to my Wi-Fi network, as well as helping me place it in a “room” within my Google Home setup. The process was over in about five minutes, and it was seamless.

For iOS, you simply go to your Wi-Fi settings, find the Mini AX’s Wi-Fi name, and then tap “Set up AirPlay speaker.”

Whether you connect the soundbar via the Google Home app or iOS, the speaker should be available for both Chromecast as well as AirPlay 2 casting once the process is completed.

Buttons, indicators, and remote

The MagniFi Mini AX has six buttons along the top, including buttons for power, input select, Bluetooth pairing, mute, volume up, and volume down.

Ben Patterson/Foundry

Peeking out from behind the soundbar’s fabric covering is an OLED display that tells you the current input and sound mode, while a nearby status light indicates the volume. The bright display is easy to read but disappears after a brief period of inactivity.

The remote that ships with the MagniFi Mini AX is a refreshing change from other Polk soundbar remotes I’ve tested. The perfectly flat buttons are gone, replaced by molded buttons that are much more tactile. Polk wisely retained the intuitive button placement, with the volume rocker right in the middle, the mute button just beneath, while bass and “Voice Adjust” controls (more on Voice Adjust in a bit) flank the volume buttons.

Ben Patterson/Foundry

AirPlay 2, Chromecast, and Bluetooth

The Polk Audio MagniFi Mini AX lacks an app for native music streaming, but you can cast audio to it via Apple’s AirPlay 2 and Google’s Chromecast, thus giving you a wide range of music-streaming options. In addition to casting music to the speaker, you can also include it in AirPlay and Chromecast speaker groups.

Besides AirPlay 2 and Chromecast, the MagniFi Mini AX supports Spotify Connect, and there’s also Bluetooth 5.0 for playing tunes on a mobile device.

Performance

For such a small soundbar, the Polk Audio MagniFi Mini AX packs a big punch. We’re talking clean, detailed sound, with tight bass, plenty of mid-range, and an impressively wide soundstage courtesy of Polk’s SDA technology. Indeed, the MagniFi Mini AX sounds better than plenty of full-size soundbars I’ve tested. I do have some nitpicks when it comes to Dolby Atmos height cues and music performance, but they’re small ones.

The MagniFi Mini AX comes with Movie, 3D, Music, and Night modes, while the aforementioned Voice Adjust buttons let you boost the sound of dialogue. Movie mode is designed to “optimize non-musical content,” meaning movies and TV shows, while Music mode is (natch) for “streaming music.” 3D mode is the one that turns on Polk’s SDA technology for virtual height effects, and it’s the one I used for most of my listening tests for movies. Finally, Night mode compresses the dynamics of the sound for late-night listening sessions.

I began my testing (as usual) with the UHD Blu-ray of Star Wars: The Empire Strikes Back, and during the frantic Battle of Hoth, I found myself marveling that such a small package was delivering such big sound. Rebel snowspeeders buzzed around my head (the surround performance would probably be even better with Polk’s optional wireless surround speaker kit), and the massive feet of the Imperial Walkers slammed into the snow with deep—but not overly boomy—thuds. I also liked the low roar of the Millennium Falcon’s engines as the cruiser corkscrewed away from a trio of pursuing Tie Fighters (I did wind up trimming the bass response to about -3). Overall, the MagniFi Mini AX’s audio sounded immersive, punchy, and exciting.

Ben Patterson/Foundry

As for the Mini AX’s Dolby Atmos height effects, they were certainly audible but subdued. When it comes to soundbars that use virtualization to achieve height cues, subtlety is far preferable to the alternative: harsh, hissy, artificial-sounding height effects that have been dialed up too far. I believe Polk made the right choice by tapping the brakes on the Mini’s height virtualization, which still gives the sound a feeling of airiness. And to be fair, there were still moments—such as when an X-Wing soars overhead as Luke boards his own ship before setting course for Dagobah—when the height cues really impress. If you want more precise height effects from an Atmos-enabled soundbar, you’ll need to get one with upfiring drivers.

Moving along to the UHD of Apollo 13, which has a DTS:X soundtrack, I could detect some nice height effects from the billowing exhaust of the Saturn V rocket as it slowly rose from the launch pad, and James Horner’s score sounded clear and crisp without veering into harshness. The dialogue during Apollo 13’s launch sequence can be tough to hear at times, but I had no trouble making out Tom Hanks’s transmissions (“Houston, we have a center engine cutoff, go on the other four?”). There was also a solid “pop” as the astronauts jettisoned the tower stage, while the ethereal music as the weightless crew took off their helmets and gloves sounded delicate and refined.

To hear how the MagniFi Mini AX handles standard 5.1-channel audio content, I teed up my Blu-ray of Wong Kar Wai’s The Grandmaster, which has a lossless DTS-HD Master Audio soundtrack. During the opening moments when Ip Man battles dozens of opponents in the rain, the soundbar did a nice job of upmixing the raindrops so they sounded like they were falling from above, while the complicated mix of thudding fists and kicks sounded clean and distinct. Even better, the subwoofer didn’t go overboard with the bassy music track.

Speaking of music, the MagniFi Mini AX managed to deliver impressive music performance, albeit in a somewhat narrow soundstage. You can opt to play tunes using Polk’s SDA-powered 3D mode, but I thought that option robbed the music of clarity, so I stuck with Music mode instead. Of course, Music mode means no SDA, and turning off the SDA collapses the Mini AX’s soundstage, essentially cutting the soundbar back to size.

To be clear, I thought the results in Music mode were still quite good given its limitations. Bruce Springsteen’s “The Ghost of Tom Joad” (which I streamed from Qobuz via Chromecast) sounded crisp and alive, with nice detail in The Boss’s guitar strumming and harmonica honking, while the soundbar deftly handled the big, growly beats of Billie Eilish’s “Oxytocin.” Again, though, the Mini AX sounds much smaller in Music mode; take Chet Baker’s “Solar,” where the performers sound distinct yet somewhat squished. For better stereo separation without the use of Polk’s SDA or other methods of digital sound processing, you’ll get the best results (generally speaking) from a wider soundbar (or even better, separate bookshelf speakers, but we are talking soundbars here). 

Bottom line

The Polk Audio MagniFi Mini AX is the best-sounding little soundbar I’ve heard yet, but who is it for? It’s a tad expensive for a second room, but small for typical home theater space. I suppose the Mini AX would be a good fit for a small living space, a studio, or anyplace where you want big sound without dealing with a full-size soundbar—and of course, providing you have the budget for it.