W20 Review – [AudioStream] The Sound of Silence

Sigh. It was inevitable, really.

Using Simon & Garfunkel’s “The Sound of Silence” as a metaphor for the Aurender W20 Music Server.

As soon as I switched over to it from the Aurender N10 the difference was noticeable enough that the song leapt to the fore of mind and I blurted out. “Shit.”

You see, it was the blackness, the even further reduction in background noise from the N10 – practically an elimination – and utter lack of tonal coloration from the unit that hit me so hard.

I should have known it was going to be like this after spending time with the N10 in my system and coming away so impressed by its sonic perfromance (Review HERE). It was Aurender’s main man Harry Lee who had warned me about jumping to the $17,600 USD W20 from the $7,999 USD N10 during a visit to our home in the spring and I hadn’t taken him seriously.

Just in case you’re late to the digital-audio game, the W20, like the N10 I reference, is a music server designed and executed specifically to replace a PC or or laptop as your source for computer-based music files. This means that all the components – from the feet, chassis, power supplies (and battery system in the W20’s case) to the delicate audio-processing circuitry and software are all holistically designed from the ground up to work together at passing along the binary information to your DAC in complete isolation from both the ambient and electronic environment around it. This is something Aurender takes very seriously and does very well.

 

Build quality and design

That the W20 weighs 15 pounds more than the already beefy 27-pound N10 should have been a tipoff that the technology in play under the similarly-clad alloy casework was not to be taken lightly (I made an unflattering noise lifting it out of the box). The fact that the W20 looks like the N10 on steroids and that it seems to be the sonic equivalent of a black hole (nothing escapes its event horizon – not even light!) left little doubt that it was was designed and built to deliver on everything that the N10 was capable of and more – or less – depending on your point of view.

This is not one of those CNC’d heavy-metal chassis sporting a one-inch thick alloy faceplate with 50-per-cent-of-the-internal-space-empty designs either… while it is packed with technology, the W20 has one of the cleanest internal layouts I’ve seen. Each stage of the server-circuit architecture/power supplies/battery/SSD–HDD is clearly delineated from one another by separate, thick RFI-shielded aluminum partitions within the chassis and all the wiring and cabling is neatly routed.

It is within one of these internal sections that the W20 houses Aurender’s unique battery power-supply configuration. The system is designed to keep delicate internal audio circuitry fed off-grid via three banks of LiFePO4 (LFP) batteries that switch between themselves to continuously supply stable power while the other banks concurrently recharge. This means the W20 is completely isolated from electrical ground noise, jitter and distortion that Aurender says can be incurred during conversion of AC to DC. The batteries are also configured as an uninterruptible power supply (UPS) to ensure all circuitry is protected from sudden power outages. Should one occur, the W20 will soft-shutdown automatically. Aurender utilizes a fanless Switching Mode Power Supply (SMPS) enclosed in a separate compartment to deliver power to non-audio components.

Incoming digital signals are routed through an FPGA-based (Field Programmable Gate Array) “All Digital Phase Locked Loop system” which is equipped with an Oven-Controlled Crystal Oscillator (OCXO) clock for minimizing “long-term jitter to below negligible levels.” How this translates exactly in practical sonic terms I can’t say, other than as previously stated; the W20 creates a dead black background – even in comparison to the already drastically-lowered noise floor of the N10, which is already significantly quieter than my dedicated, audio-only, MacBook Air.

The focus on ‘silent running’ sees in-house, bespoke-tailored circuitry designed to further provide “clean, noise-free power” to the RFI-shielded, dedicated USB Audio Class 2.0 output, and continues on to the fully-isolated and damped HDD/ SSD. Both the 12TB storage hard-disk drive and 240GB solid-state, playback-caching drive are suspended on floating brackets to minimize vibrations within their own machined-aluminum drive enclosures which Aurender refers to as “Fort Knox.” According to the company “…If a selected song or album is already cached to the solid-state drive, the hard drive will remain asleep. This minimizes wear and tear on the hard drive. By caching songs to the solid-state drive for playback, electrical and acoustic noise resulting from spinning disks, moving heads and motors are also completely eliminated.” Cool. I should add that the Aurender platform invisibly integrates any music stored on external USB drives or NAS.

I/O on the W20 consists of BNC, Coaxial, optical, dual AES/EBU and the aforementioned dedicated USB Audio Class 2.0 for output. Incoming signals travel via Gigabit Ethernet or two USB 2.0 data ports. There is also a BNC input for an external Word Clock. According to Aurender the “W20 can accept clocks with the following frequencies: Master clock: 10 MHz, 12.8 MHz, Word clock: 44.1 KHz and 48 KHz multiples from 1 to 512. There is also support for both word clock – dCS DACs or similar – or Master Clock – MSB DACs or similar – inputs.”

All of the W20’s functions and settings are accessed via Aurender’s dedicated, multitasking Conductor application, which in its latest guise, I’m happy to say, looks better, is noticeably faster and runs smoother than previous versions on my iPad Mini 2. It is one of the few player/streaming-service apps that is featured-packed enough that, same as when I reviewed the N10, had me missing Roon far less than I thought I would during both reviews. Aurender’s MQA Core Decoder is offered as an in-app purchase ($50 USD) and allows initial “unfolding” of the MQA codec for playback at resolutions of 48kHz or 96kHz which jives just fine with the totaldac d1-direct (24-bit/192kHz PCM) I was using with the W20 via it’s USB 2.0 output. Another cool function available through the Conductor app is the ability for Aurender engineers to directly troubleshoot your unit via its Router/MAC address when you log a ‘Remote Support Request.’ The app manages TIDAL and Qobuz log-ins (or even AirPlay) for streaming services (also included are a number of preset Internet radio stations, radio channels and Hi On Line Radio). Conductor displays the file type, resolution, sample rate (as does the dual 3.7-inch AMOLED chassis display) and whether it is a local or streaming-service file. The app includes cover art and descriptive incidentals. Copying files over from a NAS drive, a USB drive or even over the network wirelessly from other remote drives or computers is a breeze. After downloading an album to my laptop I log in to the W20 through the “Connect to Server” function on my MacBook Air to send files to the 12TB drive via wi-fi. A 3GB Reference Recordings 24-bit/192kHz album takes about 45-seconds to transfer.

 

The Setup

For this review the W20 was feeding into the totaldac d1-direct DAC via USB. I tried AES/EBU for comparison, but I preferred the USB input on the d1-direct – it just had more snap to my ears. YMMV. The totaldac unbalanced outputs were plugged into my McIntosh C2600 NOS-tubed preamplifier, which in turn was driving a pair of McIntosh MC611 mono blocs connected to Harbeth M40.1 loudspeakers. All analog and speaker cabling was a mix of TelluriumQ Black and Ultra Black. AC cabling was PS Audio. Clean power was supplied by a Power Plant 20. Digital cabling (Ethernet and USB) for this review was Final Touch Audio. I chose this combo for review because I am innately familiar with its sound and prior to hooking up the W20, I had been using its little brother – the N10 – for a couple weeks back-and-forth with the Roon Nucleus+ (review forthcoming).

 

Listening

My musical taste staggers to the barely discernible edges of a faint horizon and back – or drops off the edge. I’ll queue up Scottish electronic nostalgia brothers – Boards of Canada – to follow on (Billy May-era) Sinatra’s heels before subterranean bass explorations by ECM steadies the Mats Eilertsen trio and then lay down “I Fink U Freeky,” by Die Antwoord (TIDAL, 16-bit/44.1kHz) as a bridge cut to Fleetwood Mac. This isn’t the playlist of a disconsolate DJ, it’s just an example of the sonic highway I like to take gear on to get a sense of their rhythm and timing; how they handle texture, timbre and tonal colorations.

“Freeky” is a great example of a track that can help assess transient clarity and speed. Yolandi Visser (nee Anri du Toit) and Ninja (Watkin Tudor Jones) are the two halves of this electro hip-hop maelstrom out of South Africa. Visser and Jones absolute breakneck-speed rapping over the sonic horror crush of staccato synth/GameBoy/drum machine electronic noise on the cut has to be heard through the W20 to truly appreciate the level of elocution and transparency their lyrics are imbued with. Sure, I had to listen to the track a few times to pick up about half of either one’s solos because of how astonishingly fast they rap, but the lack of any smearing on those vocals in the mix through the Aurender compared to playing it through my MacBook Air was unambiguous.

“Stay As Sweet As You Are” off Nat Cole’s 1957 album Love Is The Thing (Acoustic Sounds download, Mono, DSD64) is rife with the lush orchestral arrangements of Gordon Jenkins and the cut’s spatial presentation had all the shovelled-down-the-middle goodness I’m used to from the the Analogue Productions 45rpm 2xLP I’ve been playing for years. In some ways this single-bit version betters the pressing because of the blacker background and subsequent increase of sonic information being retrieved off the leading/trailing edges of notes from the violins, cellos and of particular note – the harp. And while Cole’s voice floats lower vertically in the mix than the LP – it still was more texturally demonstrative of vocal timbre and chest emanation than throat emanation – which is a trait I associate with better sources in particular, be they analog or binary. I also want to mention what I would dub as ‘liquidity’ in the midrange on this album; the smoothness to vocals, and instuments in that 500Hz~2kHz range was of particular note.

With two opposing sides of the MQA debate set to gas each other, I admit falling into the pro-MQA camp because the mastering sounds better to my ears far more often than not when put up against other digital versions. Comparing how the W20 handles first stage MQA software unfolding I used The Beatles White Album and “Dear Prudence” (TIDAL, MQA, 96kHz). Not only does the song consistently impress me with its level of lyrical and technical-playing intelligence, it resonates at an emotional frequency within me as a result of timbrally-rich vocal overdubs, harmonies, hypnotic bass guitar and percussion in the mix. There’s more temporal air, space and decay around John Lennon’s finger-picking style (thanks Donovan) and the Twin Reverb amp output of his electric guitar (thanks Fender) than I’ve heard on any one digital or analog version previously. Lennon’s doubled lead vocals seem far more clearly defined than the CD-rip I have, and the backing singers also stand apart from one another with further clarity than my UK pressing of the album. It’s hidden details or tells in songs that are only revealed via minutiae through critical listening that I often fine the most enlightening experiences, and hearing songs through the W20 vs. the N10 and the Roon Nucleus+ gave me pause many times to reflect on its ability to render such finely-grained subtleties.

 

Conclusions

Everything I played through the W20 feeding the totaldac sounded more immediate in its presence to my listening space – more like that associated with real life music creation than an intimation of it. Music was possessed of more texture, nuance and conferred with a slightly greater breadth, height and depth to the sound stage than the Aurender N10 reviewed previously. Add in a shade more vibrancy to timbral and tonal colorations and the biggest difference of all; the low-level resolution retreival the W20’s battery-powered, dead-black background provided, and I found a compelling argument forming in my mind to upgrade from the N10 if – like I mentioned in my N10 review – your DAC and other downstream equipment is of sufficient transparency to pass along this improved information extraction. It would be disingenuous to describe the difference between the W20 and the N10 as modest – there’s just too many compelling improvements in its presentation of the recorded event. It is, however, a difference I would assign a low double-digit percentage to (say 10-15 per cent), or more, depending on what you’re coming from in comparison. Now, before you say ‘How can that justify the price difference?’ read on.

If you’re familiar with battery-powered phono stages, preamps or even some of Vinnie Rossi’s integrated amplifiers you’ve had a taste of the silence I’ve been referring to throughout this review and could understand how some cannot go back to anything else. Here’s the thing with high fidelity; often found hiding in those slim percentages is an inordinate amount of aural realism. That ‘last five per cent’ (as it’s often referred to) is usually where a lot of money gets spent by music lovers in this hobby. That cost is usually incurred because of years of R&D, tooling, machining, advanced production techniques and ever more exotic parts coming into play. But, in my experience, it is that ability to fool our lizard brains into believing someone is playing in the room with us with a sound so compellingly realistic which pushes a system from great to literal in it’s playback abilities. If you want this level of sonic performance, just like a motorcycle or a car, it is going to cost you.

Now if I only I could figure out where to get the money from.