Music in the Round

It's been going on for a while now: Despite support for multichannel in audio/video receivers and A/V processors priced from as little as $200 to $30,000, there are still very few offerings that cater to the music listener. They may offer stereo-only streaming features through their USB or Ethernet inputs, but these inputs don't see your multichannel files. To handle such files, they would require you to add a music server with HDMI output. However, I know of no turnkey music servers that will output multichannel audio via HDMI. Sure, servers based on PCs and Macs will output lossless, high-resolution multichannel via HDMI, and for years I've been running a Mac mini/Windows/JRiver Media Center server into my Marantz AV8802a A/V processor. The playback of multichannel, music-only recordings could be so much more popular if compatible HDMI output were as common as USB or Ethernet, and all were included in a reasonably priced package.

Then, on the Web, I stumbled on the Nimitra computer-audio server from Fidelizer, a Thailand-based company whose eponymous software package aims to optimize Windows as a music-playback platform. My first, immediate e-mail to Fidelizer included my standard query: Will this thing do hi-rez multichannel? To my surprise, the lightning-fast response of proprietor Keetakawee Punpeng was a definite "Yes." Still, I was doubtful. Similarly constructed servers—the Nimitra is a fanless implementation with an Intel Celeron J1900 2GHz Celeron processor, 4G RAM, and an mPCIe SSD for OS and storage—usually get indigestion when fed a rich diet of multichannel files. Punpeng assured me that by removing all non-audio functions from the Windows 10 installation and by using a special version of Fidelizer software with optimizations beyond that of the popular Fidelizer Pro version, he has greatly reduced the processing time and improved audio performance. The Nimitra also includes dBPoweramp's Asset UPnP file access and the JPlay app for streaming output.

The Nimitra ($1395) is packaged in a conservatively distinctive black case measuring 8.9" wide by 1.7" high by 7.9" deep and weighing 4 lbs, with only a single blue LED on its front panel to tell you it's awake. The standard power supply is a 12V, 5A brick, but my review sample came with a large, low-noise, regulated supply called the Fidelizer Nikola (a $495 option). The Nimitra is designed to operate "headless," controlled by an app on a Windows or Mac computer or an iOS or Android mobile device. It's meant to get input via LAN or WiFi, but it also has multiple USB inputs and outputs as well as VGA and HDMI outputs.

Setup was almost trivial. Connect the source (via USB, LAN, or WiFi), then the output (same options), and boot up the Nimitra. In about 30 seconds, using Linn's Kazoo UPnP control app on my iPad, the Nimitra-based system located the music files on my NAS. I took the quick route of two-channel output, using a stereo Mytek Brooklyn DAC via its ASIO USB driver, and was playing tunes in minutes.

But stereo is easy. Multichannel is what we're here for. There are only three multichannel DACs on the market today, and I have two of them: the exaSound e28/e38 ($3849; see below), and the miniDSP uDAC-8 ($275). My preference was to use the exaSound, as it supports DSD as well as PCM, but there was an incompatibility between exaSound's ASIO driver and JPlay that I couldn't resolve during this review period. Keetakawee Punpeng suggested a workaround using VB-Audio's ASIO-Bridge Virtual Cable software, but that wasn't compatible with DSD, and was a little fragile with hi-rez multichannel, at least in my hands. Knowing that the Nimitra could handle DSD—it did so with the Mytek, albeit in stereo—I opted for miniDSP's PCM-only uDAC-8.

The combination of Nimitra and uDAC-8 was absolutely delightful. Old standbys such as Willie Nelson's Night and Day sprang from the speakers with all the detail and zest expected from the six-channel, 24-bit/96kHz files I'd ripped from the DVD-A (Surrounded-By Entertainment SBE-1001-9), and Beethoven's Symphony 5, in a triumphant recording from Manfred Honeck and the Pittsburgh Symphony (SACD/CD, Reference Fresh! FR-718), was as dynamic and colorful as ever. However, I had fewer than 20 multichannel PCM recordings on my Connecticut server at the time, and this delightfully easy-peasy setup has no way to transcode DSD to PCM.

The answer, and my musical liberation, was to switch to music software that is not only DSD-capable but more powerful. Foobar is built into the Nimitra, and while it did the job just fine, I also preferred my two other options. I installed JRiver Media Center on the Nimitra, and it ran as well as on my other Windows 10 PCs. Considering the Nimitra's limited RAM and storage, I was surprised to find that it handled JRiver with aplomb, loading my library quickly and connecting to the uDAC-8.

I also installed the new multichannel-ready Roon 1.3 on my desktop PC; it found the Nimitra on the LAN, confirmed that it was connected to the uDAC-8, and played through. JRiver, foobar, and Roon can all be controlled with an iPad, but I'm an incorrigible mouse-and-keyboard guy. In addition, all three give you the option of transcoding DSD to 24/176.4 PCM on the fly—using the uDAC-8, I could enjoy my entire library. Even when using a DSD-capable DAC, I usually convert DSD to PCM—it allows me to use Dirac Live room equalization.

In terms of sound quality through the DAC, the Nimitra was easily the equal of the Mac mini–based server it replaced, and I felt no urge to switch back—but I also wanted to use the Nimitra's HDMI and Ethernet outputs. The Marantz AV8802a's Ethernet input is limited to stereo—a common bottleneck—and unfortunately, in the effort to slim-down all the non-audio functions, the Nimitra is shipped with its HDMI audio output defeated. I complained to Punpeng and he sent simple instructions to activate the Nimitra's HDMI audio output. After just one change in the BIOS setup, the Nimitra played multichannel signals of resolutions up to 24/192 PCM through the Marantz via HDMI, just as it should with any multichannel AVR or processor. I strongly urge Punpeng to activate HDMI audio by default so that all AVR users can enjoy high-resolution multichannel streaming with the equipment they already own.

In addition, DSD output via Ethernet to my Oppo BDP-103 universal Blu-ray player, the Oppo feeding the Marantz either via HDMI or as analog, was a revelation. Extended listening to the Nimitra via the Oppo consistently brought me the best sound, though I can't fathom why that should be.

Did the Fidelizer Nimitra have any limitations? Although it will support playback and transcoding of multichannel DSD256 and DXD files, it coughed when I installed Dirac Live in the signal path. Two solutions are to use Dirac Live's plug-in version, Studio VST (now in beta testing), or to use Roon's DSP engine to drive the Nimitra as an output device.

I tried the Nimitra with its stock power supply and its higher-quality optional supply, but heard no differences. It was dead quiet with the stock PS, so I'd consider the optional PS only if my AC were suspect.

Clearly, the Fidelizer Nimitra can do the job of playing high-resolution, multichannel music-only signals wonderfully, and it comes with all the apps you'll need for the job. Finally, a great-sounding and affordable multichannel server that works with USB or with HDMI. Hooray!.

exaSound e38 eight-channel DAC
The e38 ($3849) is the third generation of exaSound Audio Design's multichannel DAC. I've owned its predecessors, the e18 and e28 (footnote 1), and the e38 represents another strong advance. The most salient change is the replacement of the earlier ESS ES9018 Sabre32 Reference, a 32-bit, eight-channel audio DAC, with ESS's newer ES9028PRO. The e28's ES9018 chip was pushed to work with sampling rates not officially supported by ESS, and might be said to have functioned within narrow limits of stability. The new chip allows exaSound to optimize the e38's performance at DSD128, DSD256, and PCM above 192kHz, and permit faster, more stable switching of sampling rates. The analog circuitry has also been refined, to lower noise and distortion, and the new Dashboard onscreen display permits swift input switching. ExaSound's FemtoMaster option, with 82-femtosecond master clock, is now standard, but the option of balanced output is no longer available.

Like the e18 and e28, the e38 was silent in operation and absolutely stable. Unlike with them, I heard a newfound delicacy in the treble, unaccompanied by any added noise or brightness that the ambience of a multichannel soundstage might ruthlessly reveal. Clean and transparent describes it best. I also got an impression of greater dynamic range and definition, especially with massed plucked strings. This was particularly evident with the delightful Aria Italiana from Benjamin Britten's Variations on a Theme of Frank Bridge, as performed by the Trondheim Soloists on their collection Reflections (BD, 2L 2L-125-SABD). Furthermore, when I compared the sound of this track played through the e38 with Dirac Live EQ to the MQA-decoded version via the Mac-Mytek stack, I found little to choose between them. Both were outstanding at re-creating the experience of being at the performance.

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Footnote 1: Read my adventures with the exaSound e28 in my columns of November 2013 and November 2015.