Review: THX Onyx DAC amp delivers powerful mobile audio clarity [Video]

While there’s a good chance that you’ve heard of THX in reference to certification on audio hardware, today THX is announcing their first-ever consumer product. As a longtime industry titan for certifying that audio meets certain criteria, THX is bringing its expertise in audio to the mobile market. Taking everything they’ve learned and using a third-party certification, the new THX Onyx is a cross-platform DAC amp that can deliver high-fidelity audio from a mobile device with MQA studio-quality streaming. So how does it perform for the $200 price point? Be sure to hit the video below to see all of the details.

So what is it?

In an extremely simplified synopsis, Onyx is a DAC (digital to analog converter) amp for taking a digital signal from a source and converting it to analog audio to send to a pair of headphones or even powered speakers through its 3.5mm jack. As a part of that conversion, it can also decode and render MQA (Master Quality Authenticated) tracks as well. These tracks pack some extra information into the file and when decoded with a compatible device produces playback that is studio-quality – like you are sitting in the studio with a recording artist. Onyx also works to play and improve any other audio as well and provides plenty of power thanks to the THX AAA mobile amplifier. 

THX Onyx: Design and materials 

With their focus on premium sound, THX has also delivered a premium feeling DAC/amp for mobile. Housed in black, Onyx has a machined and polished THX logo that is simple yet eye-catching as well as some polished accents on the connectors. A 3.5mm jack also supports mic input, which enables the use of headsets to take calls or play games and communicate with teammates while using Onyx.

Onyx also incorporates three LED lights that can signify a few different things. When first installed, the LEDs will flash a pattern while initializing. Then, when media is played through, the LEDs will signal the quality of the file coming through. Blue signifies 44.1 or 48 kHz PCM, which is standard quality, then yellow is higher than 48kHz PCM, orange is a DSD direct stream digital, and magenta represents an MQA file that plays at the best quality. 

One other handy design feature is a magnetic connection that enables the Onyx to fold back onto itself and work as a cable tie to clean up headphone cables or just make Onyx a little more convenient for travel.

THX Onyx: Video

THX Onyx: Setup

Not surprisingly, setting up the THX Onyx is simple. Depending on the device that you are using, it’s as simple as plugging into a USB-C port on the bottom of your mobile device. You can do the same on a PC, or use the included USB-C to USB-A adapter. For Apple devices, you do need the Apple Lightning to USB Camera Adapter, which adds an additional $29 to the price. 

When hooked up to an iPhone or iPad, it’s not the cleanest setup. The combination of adapters, at least in the setup that I have here that was recommended by THX, adds just over a foot of extra cable coming out of my iPhone. 

The hardware

At the heart of the Onyx is the THX AAA Achromatic Audio Amplifier. With 5x the power as similar USB DAC/amps, it can put out a ton of power but keeps things clean with ultra-low distortion and noise. 

THX AAA amplifiers have been used in many other products as well, and for mobile devices, namely the Drop Panda wireless headphones, and are well regarded for their performance in mobile devices. But, this is the first time that the THX AAA-78 has been used in a mobile device that delivers ultra-low noise and significant power. 

Onyx also features an ESS ES9281PRO DAC for rendering studio sound quality. 

THX Onyx and MQA

Since THX is in the business of certifying audio devices with a certain quality level, it didn’t really make sense for them to certify themselves. Onyx has been independently tested and certified by MQA’s engineers to ensure that it preserves audio quality throughout the signal range with high quality and the maximum resolution. 

Furthering that relationship with MQA, the Onyx can decode and render MQA files. From the THX press kit,

“MQA is a breakthrough technology that enables music fans to stream the original master recording into their home, car, or on their mobile.”

THX Onyx press kit

These files will work on any device, but to take advantage of the extra quality packed into MQA tracks, a device with an MQA decoder is required – like the THX Onyx. 

A very basic explanation of what MQA is doing to streaming media to make it better than CD quality is that the MQA process cleans up an audio track to remove distortion and noise, which makes it easier to pick out individual instruments and voices and then packages that information into a file by “folding-in” extra data that can only be decoded by a MQA-compliant device. 

It’s a lot more complicated and impressive than that brief explanation, but if you want to read more about what MQA delivers, their website has a nice write-up.

Streaming studio-quality audio

While there are a few different sources to get these MQA tracks, one of the easiest ways to stream music is  to sign up for a TIDAL HiFi membership. For $19.99, TIDAL’s Master tracks are MQA guaranteed recordings that are directly from the master source instead of going through a distributor’s, like Spotify or Apple Musics, music rendering. This ensures that the audio on a Master track is exactly as the artist intended the track to sound.

So how does it sound? 

No matter what kind of file you’re listening to, the THX Onyx gets crazy loud. Right when opening the box there is a card with a warning for high volume that also gives a few steps to take before you listen to music to prevent any ear damage. Ensure that the volume is turned down before starting any playback on a mobile device.

One of the main things to listen for when using the THX Onyx playing MQA files is clarity. Mainly picking out individual instruments and voices more easily. Thanks to that work to reduce distortion cleaning up tracks, it’s much easier to pick out individual instruments in a track and reveal things that you might not have heard before.

I did most of my listening through the Philips Fidelio X3 headphones, which might not be the best choice for a true mobile listening setup thanks to their open-back design, but they’re my favorite pair of headphones in my possession, and they have an incredibly wide soundstage, which makes them great paired with the THX Onyx. 

Compared to a standard Apple Lightning to 3.5mm adapter, listening to “How Do You Sleep” by Sam Smith on Onyx rendered a noticeable difference that made it easier to pick out intricate vocal lines. I could always hear the harmony with other setups, but the MQA file and Onyx combo made it easier to actually pick out the separate voices. 

Likewise, “Simmer” by Haley Williams revealed even more detail that I’ve previously heard thanks to the Onyx/MQA combo. It has been a fun way to revisit some of my favorite tracks. 

Music also sounds fuller and more vivid. That might be thanks to THX’s claimed improved dynamic range, but back to “How Do You Sleep” by Sam Smith, the low end sounded more impactful and clear than when using the standard Apple adapter. When my wife compared the two, she also stated the THX Onyx was “a treat” to listen to, noting an increase in clarity. 


Beyond just listening to music though, THX touts the performance of the Onyx for other media like gaming and watching movies. I tried the THX Onyx while playing Call of Duty Warzone, and while it did sound good, I didn’t notice a huge improvement over just using the Behringer U-Phoria UM2 that I typically use to power my Philips Fidelio X3 when gaming.

9to5Toys’ take

THX Onyx isn’t the first DAC amp, and it isn’t the first device able to decode MQA, but its combination of technology makes it stand out in the crowd. The cross-platform functionality with the powerful THX AAA and compatibility with headphones and headsets makes it ready for almost any application. Combine that with the incredible detail found in MQA tracks like those streaming from TIDAL, and it is an incredible way to listen to music from a mobile device. Sure, it’s not as convenient as a wireless option like the Drop Panda, but if the utmost in audio quality is what you’re after, the THX Onyx paired with a good pair of headphones is some of the best that I’ve heard. 

Buy THX Onyx 

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