Aurender W20 Music Server

Not Just a Pretty Interface

Equipment report
Music servers and computer audio
Aurender W20
Aurender W20 Music Server

Does the W20’s $17,600 price tag buy you merely the convenience of a turnkey server and a nice interface, or does it sound considerably better than, say, a fully tricked-out MacBook Pro? (There’s no question that the user experience is vastly better with the Aurender than with the Mac-based server. In fact, the comparison’s not even close.)

To answer that question I first assessed the W20’s sound quality by auditioning its various digital outputs to find the best interface. I found that the best-sounding configuration was with the W20’s USB output driving a Berkeley Alpha USB (a USB-to-AES/EBU or SPDIF converter), which in turn fed the Berkeley Alpha DAC Reference via a 1m run of AudioQuest Wild Digital AES/EBU cable.

The W20 was put under the extremely powerful microscope of the state-of-the-art in digital conversion, the Berkeley Alpha DAC Reference connected to some of the most transparent and resolving electronics extant—the Constellation Audio Altair 2 and Hercules 2, or the Soulution 725 and 701 combos. These, in turn, drove the Magico Q7 Mk2 and MartinLogan Neolith loudspeakers, all connected with MIT’s best cables. The listening room’s AC power, supplied via four dedicated 20-amp AC circuits, was conditioned by an all-out Shunyata system with the new Shunyata Sigma AC cords. This system’s resolution immediately revealed exactly what was happening at the digital source. (I’m reviewing the new Constellation electronics and the Neoliths in the next issue. Shortly thereafter, I’ll write a feature article on building this entire system and what I learned along the way.)

Listening to the W20 on a daily basis, after living with a MacBook Pro as a server for the past year, I was immediately aware that Aurender’s extraordinary efforts in clocking, buffering, and lowering noise paid off in the musical experience. The W20’s “sound” was characterized by a natural and organic quality that came closer to the “feel” of analog than any digital source I’ve experienced. The presentation had a dimensionality, life, bloom, and illumination that one doesn’t associate with digital. I was repeatedly amazed by just how much space and depth were encoded on 44.1kHz/16-bit sources, just waiting to be revealed by playback hardware of this quality. I thought that we had long ago bumped up against the limits of standard-resolution digital sources, but the W20 feeding the Berkeley Alpha Reference DAC showed that the flatness, hard timbres, lack of air and depth, and absence of fine detail were not purely attributable to the standard-resolution digital format. Of course, there are many inferior-sounding CDs, but the W20 still managed to get the most music out of them. The W20 not only revealed new depth and dimensionality on well-recorded CDs I had ripped (in AIFF), but also rendered instruments as separate objects in the mix. The W20 “de-homogenized” the soundstage, allowing me to hear each instrumental line with startling clarity and focus. Reverberation decay was longer and deeper, adding to the impression of space and dimensionality. The recording Live in America by flamenco guitarist Paco de Lucia was a particularly vivid example: Paco’s guitar was focused in the center of the stage, surrounded by the hall’s dense reverberation, with the thrilling zapeteo (percussive footwork) and handclaps at the far left and right boundaries “lighting up” the acoustic space with each sharp transient. I’ve listened to this track many times, but never before felt I was hearing the recorded acoustic this clearly. The experience was mesmerizing.

In addition to greatly increased dimensionality, another salient characteristic of the W20 was its very quiet background. It was as though the W20 cleaned up a bit of low-level hash that was diminishing the impression of hearing instruments in space. Presented against a dead-silent backdrop, instruments took on more palpability, realism, and life. This low-level hash had also set a noise floor below which no information was being resolved. The Aurender’s deeper silence allowed very fine details of timbre, micro-dynamics, and ambience to emerge. The W20 was so adept at resolving the lowest levels of information that I consistently heard new musical nuances on albums I’d been listening to for decades. Treble through the W20 was cleaner and purer, with less grit, hardness, and unnatural sheen. The top end had greater delicacy, air, and detail—qualities that were rewarding on Jack DeJohnette’s wonderful cymbal work on the live Keith Jarrett recording My Foolish Heart. Cymbals seemed to float in air rather than being painted on a flat canvas; their airiness and decay approached that of analog with some recordings.

There was a sense of precision and order that made the music tight, defined, detailed, and dynamic. Bass was tauter and more tuneful, with greater pitch articulation and dynamic impact. This precision was particularly impressive on 44.1kHz/16-bit sources. Although the best hi-res material sounded spectacular, what impressed me even more was how the W20 reproduced standard-res material day after day. It was as though the Aurender had remastered my entire CD library, giving me new and improved versions of old favorites. In some respects, realizing great sound from standard-resolution sources is a greater technical challenge than performing the same trick with hi-res ones; on Red Book CD, the digital source and DAC have much less information to work with, leaving no room for error.

The W20 was significantly better sounding than the MacBook, even though both sources’ USB outputs were being buffered, isolated, and reclocked by the same Berkeley Alpha USB. (I suspect that the difference in sound quality between the MacBook and the W20 would be even greater if the latter were driving DACs directly, without the Berkeley Alpha USB interface.) It did not take hours of back-and-forth comparisons to hear the W20’s superiority. I started by listening to “Back Row Politics” from Act Your Age by Gordon Goodwin’s Big Phat Band, first on the W20 and then through the MacBook Pro. The tune starts with few bars of piano intro. Switching to the MacBook Pro was almost like hearing a different piece of music. Through the MacBook the left- and right-hand piano lines were blurred into a single musical statement. Through the W20, the two lines were clearly distinct, and much more musically involving, the interesting meter generated by the left and right hands setting the stage for the rest of the tune. When the band came in, I heard a much tighter and deeper bottom end, a more open and spacious soundstage, and far more detail. Small percussive details smeared by the MacBook were rendered with pristine clarity by the W20. I had been listening to the MacBook Pro for about a year, and was surprised by just how much better my system sounded with the W20 as the source.

The Aurender W20 is in my experience the current state of the art in music servers. It excels in every parameter; its array of features is unmatched, the 12TB of available storage will accommodate virtually any library; its interface is wonderful and intuitive; and most importantly, it delivers sound quality unmatched by any other digital source I’ve heard. The W20 brought out the best in my system, delivering the greatest dimensionality, timbral purity, resolution, and freedom from hash I’ve heard from digital sources. Of course, a great digital-to-analog converter is required for realizing the sound quality I’ve described, but I can say that the combination of the W20 and the Berkeley Alpha DAC Reference sets a benchmark in performance.

Although many listeners will be drawn to the Aurender W20 by its capabilities and outstanding iPad control app, it’s really the sound quality that makes the W20 special. The Aurender W20 is not just a pretty interface.


Storage capacity: 12TB (6TB x 2)
Formats supported: DSD (DSF, DFF), WAV, FLAC, AIFF, ALAC, M4A, APE, and others
Outputs: AES/EBU (x 2, single-wire or dual-wire mode), USB 2.0 (dedicated audio output), USB data ports (x 2), TosLink optical, Ethernet, coaxial (RCA), coaxial (BNC)
Inputs: Clock on BNC
Network: Ethernet
Dimensions: 16.93" x 4.17" x 14.57"
Weight: 41.9 lbs
Price: $17,600

209 N. Victory Blvd.
Burbank, CA 91502

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