Roon review (Part 2b – Walking on Airplay)

In Part 2 we saw how Roon comprises three components – a library-managing Core, a (remote) control Client and a playback Endpoint – all of which can be installed and run on a single machine. Alternatively, Roon duties can be spread across two or more machines on a home network: running the Roon installer, all three components are installed on each machine with one assigned as Core and the second as Endpoint. The control Client can be used on either of these two machines or even a possible third device.

At time of writing Roon only runs on Windows and OS X but there’s a beta version of the Android version now running out in the wild.

Then there are digital audio hardware manufacturers who are partnering with Roon to unleash its network audio potential in their products.

Endpoint compatibility is reportedly ‘coming soon’ to PS Audio’s second version of their Network Bridge, a streaming-capable card that slots into the rear panel of PerfectWave and DirectStream DACs. On this Paul McGowan says, “So far it is a 50/50 that there will be enough room in Bridge II to accommodate the code snippet required – we are waiting for Roon to release something to us to see. Bridge II is now shipping so if Roon gets moving we can add it via firmware update.” 

Can you sense the hunger? Understandable too. From where I’m sitting, Roon is a long overdue evolutionary leap in digital audio delivery and library interaction.

With the Aurender N100H server arriving for review last month I pinged the Seoul company’s mainman Harry Lee about possible future Roon compatibility. He’s also on board as one of the early collaborators but says, “The [Roon] SDK release to early manufacturing partners was delayed from July 1st to September.”

Mark Jenkins of Antipodes Audio all but confirmed the (northern hemisphere) Autumn scheduling but also suggests reasons for the schedule slippage. “We think we will get what we have requested from Roon in September. They have only three guys to do the work and a lot of work planned so it is hard to be definitive. So maybe 3 to 6 weeks away,” he says. Jenkins plans to implement Roon code into his range of Linux servers.

Endpoint behaviour is also reportedly coming to the AURALiC Aries (and probably the Mini) as well as devices made by Meridian and dCS.

But if you want taste of the flexibility that an outboard Endpoint can bring to home network audio, or if you’ve not the stomach nor budget for high-end streaming/serving solutions, I have good news for you: Roon can stream to any Airplay-compatible device.

The obvious starting point here is an Apple TV (US$69). The machine running Roon Core, in my case a late-2014 MacMini, recognises the junior Apple device automatically leaving me only to specify it as the intended playback ‘zone’ and hit play. Et voila! Tunes are streamed across the network to the Apple TV which spills with bits over toslink into the connected DAC. Wallet watchers are directed to toward the Schiit Modi 2 ‘Optical’ (US$99) or, if USB requires are foreseen down the line, the Modi 2 Uber (US$149).

There are a couple of limitations here. The Airplay protocol streams only at 16bits and 44.1kHz.

From Wikipedia: “The AirTunes part of the AirPlay protocol stack uses UDP for streaming audio and is based on the RTSP network control protocol.[8] The streams are transcoded using the Apple Lossless codec with 44100 Hz and 2 channels encrypted with AES, requiring the receiver to have access to the appropriate private key to decrypt the streams.[9] The stream is buffered for approximately 2 seconds before playback begins, resulting in a small delay before audio is output after starting an AirPlay stream.”

That’s all fine and dandy for CD rips and Tidal streaming but hi-res material will see downsampling to 16bit/44.1kHz. The Apple TV is also short on Bitperfect respect with incoming data streams upsampled from 44.1kHz to 48kHz before being dispatched from the optical port. During my listening tests, Resonessence Labs INVICTA DAC confirmed as much: always 48kHz.

Dropping an extra US$30 on the Apple Airport Express (US$99) will give you Bitperfect playback of 16bit/44.1kHz material as it too comes loaded with an optical digital output.

Besides, the lack of bitperfect playback in the Apple TV is a dust-speck-sized complaint in the context of its asking price – absurdly cheap for a Roon Endpoint that also doubles up at Netflix and YouTube streamer.

The trouble with these Apple devices being so downright affordable is that, in an isolated Roon Endpoint context, they seriously blunt the competitive edge of the likes of the AURALiC Aries and Aurender N100H which also offer Airplay. Admittedly, this functionality but is probably of low priority for the would-be buyer of deluxe steamer or server but still.

Like Harry Lee and Aurender, Xuanqian Wang’s commitment to low-noise designs means his AURALiC Aries streamer-come-server is a better sounding digital transport than a MacMini, even when the latter is pimped with luxury USB cable, USB converter and/or noise filter like the AudioQuest JitterBug or Schiit Wyrd. With all three in play the fully-tricked out MacMini gets alarmingly close to the Chinese streamer…close but no cigarillo.

Back to Roon Airplay Endpointing. Fire up AURALiC’s Lightning DS app on an iPad or any Android device to nudge the server away from local and cloud libraries and into Airplay-only mode; look for the Airplay logo on the Aries’ display for visual confirmation. Moving on up from the Apple TV to the Aries’ coaxial output brings small rewards – richer tonality, a larger soundstage and a greater sense of lubricity. Deploying the USB output whilst in Airplay mode gave nothing but a distorted signal; another bug to squash for Mr Wang’s already over-burdened team of software engineers.

What kicked off this Airplay experimentation wasn’t the Apple TV itself but the Antipodes DX, easily the finest sounding music server I’ve heard to date. With a Vortexbox engine, the DX uses Squeezebox Server and the ICKStream plugin to administer locally-hosted tunes and Tidal respectively. Its UX feels clunky and dated when sat next to Roon.

However, with the Squeezebox Server’s 3rd party Shairplay plugin installed – software that behaves as an Airplay receiver – a thought bubble popped into being. It read: “What if I could stream direct from the MacMini’s Roon Core to the DX’s Shairplay?”. Would Airplay streaming to the Antipodes box not net the best sound possible prior to Mark Jenkins adding RoonSpeakers and Roon Core to his servers’ Linux operating system?

In theory, yes but when it came to the crunch, computer said no. The DX presented as an Airplay device through Ethernet wiring to the Roon Core-d MacMini but with playback let loose we get nothing but noise. Noise that’s best described as having whitish tendencies. Imagine music being sped up prior to a near-field blasting from the audio equivalent of pebble-dash. An iPad 2 streaming directly to the DX via Airplay works just fine.

Of course, once companies implement Roon Endpoint (and Roon Core) functionality using Roon Labs’ own protocol (RoonSpeakers), the need for Airplay and its software emulation troubles each evaporate. Moreover, the streaming ceiling for Roon-equipped streamers/servers will enjoy a lift to accommodate hi-res source material sans down-sampling.

RoonSpeakers streaming will also return proper gapless playback that Airplay appears to omit. The audible gaps aren’t large – a split second at most – but enough to disrupt the rhythmic flow of a DJ mix or classical piece.

Those finding contentment with the Redbook-restricted and gapless-less compromises of an Apple TV Roon Endpoint could pocket the money saved from not upgrading to a ritzier streamer or redirect it towards a S/PDIF re-clocker like the Wyred4Sound Remedy or Empirical Audio Synchro-Mesh. Either way, they’d end up quids in.

Do not underestimate the per pound power of the Apple TV.

Further information: Roon Labs | Apple | Aurender | AURALiC | Antipodes Audio