No DD, no DICE
Pros: Easy to use, great sound quality, simple pairing, long range
Cons: No rechargeable case, lacks hi-res Bluetooth support
UTWS1: has FiiO made the world’s best true wireless IEMs?

64Audio are not renown for their wireless products, in fact I don’t think they make any wireless products at all.

Except thanks to Chinese audio giant FiiO, they now do. And by plugging my very-much-wired 64Audio U12t IEMs into FiiO’s new UTWS1 Bluetooth adapter, I may have found the world’s very best true wireless IEMs.

Ok, so the headline was (only slightly) misleading, and this review isn’t really about IEMs. Except it is, but not just my IEMs – any IEM. The beauty of the FiiO UTWS1 is that it works with just about any IEM with an MMCX or 2-pin connector, which means just about every IEM ever made.

But can this little wireless wonder really ditch the cable and keep the sound quality of a wired connection?


In the box

The FiiO UTWS1 is shipped in a small, unassuming square box, inside of which you’ll find the twin earpiece receivers inside a patterned zip-up carry case. Included in the case is a twin-headed micro USB cable, used to charge both earpieces simultaneously.



It’s a shame FiiO couldn’t figure out how to design a rechargeable case for the UTWS1, but then this is no ordinary true wireless device, and a case would have had to account for different sizes and shapes of IEMs.

The case supplied, and the earpieces themselves, are very well made, as you’d expect from any product bearing the FiiO logo. Each earpiece contains an elongated cylinder that fits behind the ear and houses the ‘smarts’ of the Bluetooth DAC and amplifier, along with a pushbutton and microphone.

A short, curved rubbery cable extends from each cylinder, designed to ergonomically fit around each ear. The cables are marked with red and blue rings around the MMCX connector version to denote right and left respectively, but oddly not on the 2-pin version.

They may seem a bit bulky at first, but the earpieces are very light, and the cable sits flush. Once in place the earpieces disappear behind the ear, and don’t cause any discomfort even after hours of continuous use.

Since I only have the 2-pin version, I can’t vouch for the quality of the MMCX connectors, but FiiO’s build quality track record is a good one. Overall, this is an impressive package, for what it is.





Features and functions

With Qualcomm’s QCC3030 Bluetooth 5.0 chip inside each earpiece, the FiiO UTWS1 supports Qualcomm’s ‘CD-quality’ AptX codec, along with standard AAC and SBC. I consider it a missed opportunity not to include support for AptX-HD and LDAC, though doing so would likely have resulted in significantly higher power consumption and licensing fees.

As an aside, this codec limitation isn’t unique to FiiO, but rather a marker on where we are with true wireless technology. Even Sony’s own true wireless IEMs don’t support LDAC – in fact they don’t even support AptX. That said, Bluetooth codecs are just one variable in the sound quality equation.

The UTWS1 works like most other true wireless systems in that each earpiece functions independently, but ‘syncs’ with the other earpiece when both are active, hence the ‘true wireless’ designation. The entire system works using low-powered and very efficient Bluetooth transmission, so despite the name, there’s no Wi-Fi involved.


Since they work independently, you can use the UTWS1 earpieces like you would any other single receiver walk-and-talk earpiece, the microphone and push button giving you call answer functionality when connected to a smartphone. Or sync them up for the full stereo experience, even with calls.

While not strictly part of this review, I tested the call quality while connected to my phone, and found it to be excellent, perhaps a factor of the noise cancelling features of the Qualcomm chip. The incoming call also paused and resumed the music I was playing, which is handy.

Pairing the earpieces was as simple as holding down the button on an earpiece for five seconds until the small LED light starts flashing red and blue, at which time it should appear on your device’s available Bluetooth list. Once paired with your phone or DAP, power up the other earpiece and it will automatically ask to be paired with your device. Once that’s done, both earpieces will be paired and ready to play.

The button on each earpiece is programmed to perform numerous functions: click once on the left and right to lower and raise the volume, twice on the right to pause/play the music, hold down the left for two seconds for previous track and right for next track, and hold down for three seconds to power off. For some reason I couldn’t answer a call by using the button on either side, nor pause/play the music by double-clicking the right earpiece, so perhaps these features aren’t universal and depend on your source device.

Lastly, should you want to take your listening outdoors, the earpieces have a nano coating that supposedly protects them from splashes and sweat, which makes them great for taking along for a run or to the gym. Forgive me for not putting this to the test with the U12t, though!



Sound quality

Let’s face it, there’s no substitute for wired sound quality. Bluetooth has come a long way since it was invented to transmit low bandwidth MP3 files, but even with the latest ‘hi-res’ Bluetooth codecs, there’s still a perceptible loss of quality with resolving IEMs, and they don’t come much more resolving than the 64Audio U12t.

But there’s a catch. You’re not always going to want to use your high-performance IEMs for Bluetooth music for this exact reason. The compression that’s only mildly apparent with lesser gear is suddenly blatantly obvious. Even if you’re getting anywhere near the maximum bitrate of AptX, that’s still well short of the bitrate of a CD-quality lossless flac file, let alone hi-res.

Throw in poorly recorded or mastered music and the cumulative result is a pale shade of what your IEMs are capable of. This is no fault of the UTWS1. In fact, with the right IEMs, it blows away just about any other true wireless IEMs available today. It’s purely a limitation of the Bluetooth protocol, combined with the far weaker amplifiers used as a necessity for wireless convenience.

That said, I found the sound quality of the UTWS1 surprisingly impressive. Being careful to select well-mastered music, I missed my cable far less than I thought I would, especially since I was able to untether myself from my phone and DAP and walk around the house without a worry.

If I have to be critical, it was immediately apparent how the smooth, pristine vocals in Lily Kershaw’s sublime “Unrequited Night” started to sound slightly wobbly in parts, and the electronic drums didn’t hit quite as hard or with as much texture on Lorde’s “Royals”. Switching to classic rock, Boston’s “More Than A Feeling” left me wishing the vocals sounded fuller and the guitars had more crunch, and the violins weren’t nearly as precise on Max Richer’s “Winter 1”.

Again, this is no real fault of the UTWS1. For a true wireless system, it performed well above what I expected. “Well obviously,” I hear you saying. You can’t compare a $2,000 IEM to your typical $200 or $300 true wireless set. Except with the UTWS1 you can do just that. If you already own high-performance IEMs, the UTWS1 will turn them into high-performance true wireless IEMs for the sum total of $45.


Closing thoughts

FiiO isn’t the first company to come up with a universal true wireless solution for third-party IEMs, but the UTWS1 is by far the most polished, capable and practical device I’ve seen on the market to date.

From the clever packaging to the well-made, lightweight, comfortable earpieces, the UTWS1 appears to be seamlessly compatible with almost any IEM, with just the right balance of features and functions to make it more than a one-trick wireless pony. It may not tick all the boxes when it comes to Bluetooth codecs, and FiiO warns against using super-sensitive IEMs that might pick up some noise from its powerful receivers, but with the right combination of earpiece, you can get a lot of utility for not a lot of money.

True to form, FiiO have delivered when it comes to bang-for-buck with a product that doesn’t look out of place alongside high-end IEMs, phones and DAPs. You’ll be paying significantly more for a ready-made set of true wireless IEMs without any guarantee of better quality, especially if you already own a pair IEMs you know and love.

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Both units needed to be cleared before they can be paired successfully. Powered off both units then, press and hold power button of the left unit for 10 seconds, until the led flashes red/green and beeps 3 times and it powered itself off, do the same steps to the right unit. These steps would cleared the pairing memory of the units. To repairing, ensure the two units are set close to each other, press and hold the right unit's power button until its' led flashes red/green(entered the pairing mode), start pairing it to your device. Once the right unit paired, press and hold the left power button to power up, the green led flashes, look for bluetooth name "headset", click on it then it will pair, after it paired it will change from headset to FiiO UTWS1 L.
After seeing two units pair on the Bluetooth screen, streaming to FiiO UTWS1 R audio would stream to both left and right units, streaming to FiiO UTWS1 L audio would stream to only left unit.

Or follow the instructions comes with it on section how to clear pairing. Hopefully, this would help. Enjoy Bluetooth music.