January 2015

Calyx Audio M2014 seemed to be the year of the portable high-resolution music player. Pono was finally released, Astell&Kern released the magnificent AK240, and then came the M, from South Korean manufacturer Calyx Audio.

I was asked to compare the M with A&K’s AK240. No way. The AK240 has many functions absent from the M -- though each might be the best in its price category, the price difference is significant. At $999 USD, the Calyx M costs a lot less than the AK240 at $2499, and you get less: no Bluetooth or Wi-Fi, thus no wireless connection to music stored on your computer -- and no form-fitting protective case. But what you do get with the Calyx M is very good, and makes it a reasonably good value . . . once the bugs are worked out.

In the box

The Calyx M comes with a soft carrying pouch and two USB-to-USB Micro charging cables, one short, one long. Its gorgeous copper color is matched by the cables. There’s no quick-start guide -- you download the instruction manual.

At 5.25” x 2.75” x 0.5”, the Calyx M is large -- about the size of a new iPhone 6 or Samsung phone, but thicker. Its 7.7 ounces felt a bit heavy in my hand over long periods of use. The front is almost all screen -- a handsome, 4.65”, high-definition (1280x720) OLED display covered with Gorilla Glass. On a tiny strip below the screen is an “M.” The rear panel is all smooth metal, with Calyx’s engraved treble-clef logo and manufacturing information -- the fine print. Along the top edge are a 3.5mm jack, slots for SD and MicroSD cards, and an On/Off button. On the bottom is the USB Micro jack for charging.

The M’s left edge is blank, but ranged along its right edge is a magnetic slider for volume, and Play/Pause and Forward/Back buttons. The slider can be removed; you can change the M’s settings so that its volume level is controlled with an onscreen slider. Some might fear that the magnet would fall off or be accidentally triggered, but I saw little possibility of that. The magnet is held on solidly -- it took brute force to remove it, and it and the three function buttons don’t protrude far enough to be set off by accident. The Calyx M seems generally very solidly built. I’d never deliberately drop anything I’d spent $999 on, but I have a feeling that if I did so by accident, the M would probably survive.

The M will play files in the MP3, FLAC, WAV, AIFF, AAC, MP4, and OGG formats, at sampling rates from 44.1 to 384kHz and word lengths of 16 to 32 bits. It also decodes and plays DSD64 and DSD128 files. The claimed frequency response is 20Hz-32kHz, with a very impressive channel-separation spec of 130dB at 1kHz.


I loved listening to the Calyx M, but I didn’t enjoy using it at first. The On/Off function seemed to behave differently each time I pushed the button. On startup, “Calyx M” briefly flashes on the screen, which then alternates a featureless black screen with the Calyx logo, until a porthole opens that instantly reminded me of the cover of 10cc’s Deceptive Bends. Through the porthole you can see the cover of the album you’re playing; if you put your finger at the center and hold, the full cover pops up -- it can look crazy good on that OLED screen. But no information is displayed in album-cover mode, and no control options -- no play, skip track, etc. For that, you have to let the M cycle back to the porthole, where you can play, skip, or tap Track Info, which reveals an incredible amount of information: performer, album title, file name and type, resolution, and memory. Swipe left to get the Jukebox, where you can add and subtract files or albums and compile playlists. I don’t do this often, but I’m sure many people would find it a great asset.

Swipe right to access your library, complete with album covers. The scrolling action to find a title is smooth and steady, or you can shorten your search by tapping one of the letter indicators on the scroll strip along the right side of the library screen. Again, the bright OLED screen made it fun to see and browse the thumbnail covers. Tapping the three dots at the upper left of the screen brings up Settings, which first tells you how many gigabytes of storage you’ve used and how many you have left. Then you can lock or unlock the screen and hardware buttons, and set the screen for time, date, language, library scan (which refreshes your library information), and enable gapless play. Settings also lets you choose between the magnetic or the onscreen volume slider, and reset. The most unusual feature in this menu is impedance matching; there are Low, Mid, and High settings, to optimize your headphones’ performance.

Calyx Audio M

The M comes with 64GB of storage, which can be expanded with SD cards. Chris Zainea, Calyx’s US rep, and I figured that adding the maximum sizes of SD card (256GB) and microSD card (128GB) would give you 448GB -- impressive for a portable player. But those high-capacity SDs are pricey.

To turn the M completely off, you hold down the On/Off button. You then get a message asking if you really want to exit. Tap Yes and you’re off. It’s important to know this -- apparently, the Calyx M has no fail-safe off feature. I charged it, then left it lying around for two days, and when I picked it up again, the battery was dead. Lesson: The battery will drain quite quickly if the M is left on -- remember to turn it completely off if you won’t be using it for a while.

The usable battery time itself was a problem. Zainea told me that I could get 4.5 hours playing high-resolution material, but the most I ever got was three hours, and that was with a mix of standard- and hi-rez recordings. If you want to listen to a Wagner opera, either listen while charging (connected to a 5V supply) or be prepared to take a long intermission to recharge the battery.

At first, I found the Calyx M erratic in its responses to my finger taps and swipes. But this is the age of the Internet, and firmware updates are the rule. During my first three weeks with it, one firmware update was released. This was easily installed by downloading it and dragging to the Calyx in my computer, once the USB connection to the computer was established. Just before deadline, another firmware update made the M’s erratic performance a thing of the past. It now performed all of its functions quickly and accurately. What a difference!


In the sonics department, the Calyx M shone. Its evidently marvelous DAC reproduced sound with warmth but no loss of detail. What it seemed to do best was tighten up the sound, much like focusing a camera lens. It did this for all types of music, while producing no background noise other than what was on the recording itself. I did a little listening through headphones, but mostly I hooked up the M to my main audio system with a 3.5mm-to-RCA stereo cable and listened through my speakers. I believe that the M’s focused sound had something to do with its excellent channel separation.

Claire Martin has become my favorite contemporary jazz singer. Not only is she incredibly talented, she records for Linn Records, who provide her with audiophile-quality sound. I had Martin’s Too Darn Hot! (24-bit/96kHz AIFF, Linn) loaded on the Calyx. It opens with “Something’s Coming,” from Leonard Bernstein’s West Side Story, which begins with the cacophonous sound of overdubbed saxophone, piano, and struck cymbals, then settles into a more traditional sound of voice, piano, bass, and drums, with stringent sax commentary. The AIFF file sounds darned good through my Squeezebox Touch, but through the Calyx M it was a bit more solid, and the positioning of each instrument -- and Martin’s voice -- was better defined. The sound was tight but not dry.

Calyx Audio M

As my friend Richard Freed has pointed out, Gustav Holst’s suite from The Perfect Fool, with Sir Adrian Boult conducting the London Philharmonic (24/96 AIFF, Decca/HDTT), is a great demonstration piece -- almost a brief concerto for orchestra. Every instrument gets a say, even the double basses, and hearing it through the Calyx M was a near-magical experience. All of the delicious details of Holst’s orchestration and Decca’s engineering were audible without strain on a wide, deep soundstage that lost none of that detail. I’d never heard this familiar recording sound better.

I went on to listen to much more music through the Calyx M. It seemed to invite me to hear all of my familiar recordings -- classical, rock, jazz, anything -- in a new light.

In sum

Calyx Audio MThe Calyx M is a great-sounding portable player that includes native DSD decoding and works with just about every other format and sampling rate. It has a beautiful OLED screen and an attractive copper finish. It’s big, but its considerable internal storage is greatly expandable with SD cards. If you buy an M, make sure it comes with the latest updated firmware, or expect to download and install it yourself. Firmware updates have corrected most if not all of the Calyx M’s operating anomalies, but I doubt an update can do anything about its hunger for battery power -- a charge won’t last long.

I wouldn’t buy a Calyx M sight unseen. Try it yourself, to see if its operating system is satisfactory and if its size agrees with your lifestyle. I have no pockets big enough for an M, but some people must, considering the huge smartphones they buy (though such phones are seldom as thick as an M).

But I can’t imagine the M’s sound disappointing any listener, even the most critical.

. . . Rad Bennett

Associated Equipment

  • Speakers -- MartinLogan: Ascent (main), Theater (center), Aerius (surround), Depth (subwoofer)
  • A/V receiver -- Yamaha RX-V661 (used as preamplifier)
  • Power amplifier -- Outlaw 750
  • Sources -- Oppo BDP-83 universal BD player, Sony BDP-S5100 BD player, Oppo DV-980H DVD player, Samsung BD-UP5000 BD/HD DVD player, Logitech Squeezebox Touch digital player, Psyclone HDMI switching box
  • Headphones -- Outdoor Technology Privates Bluetooth, Audio-Technica AX515 Sonic Fuel

Calyx M Portable Media Player
Price: $999 USD.
Warranty: One year, limited.

Calyx Audio
414 Kumkang Venture-tel
1108 Bisan-Dong, Dongan-Gu
Anyang-Si, Gyeonggi-Do 431-050
South Korea
Phone: +82 31-422-5690
Fax: +82 31-422-5633

E-mail: ask@calyx.kr
Website: www.calyx.kr  

North American distributor:
On Song Audio Distribution
7644 Julie Drive
Portage, MI 49024
Phone: (844) 225-9961

E-mail: calyxm.us@gmail.com
Website: www.calyxm.com