How To Decode And Play Auro-3D Music On A Mac

Last week I wrote about Dolby Atmos downloads. Shortly after publishing the article I was reminded of Bert van der Wolf from The Spirit of Turtle. Bert is a recording engineer and producer based in The Netherlands, who has long been involved in immersive audio at the highest levels of quality. I first visited Bert at his studio way back in September of 2011, as part of a trip for a dCS event at Rhapsody Sound & Vision, where dCS showed DSD over PCM (DoP) for the first time. 

Bert's studio was full of dCS and Spectral Audio components, and Avalon Acoustics loudspeakers, among other well respected brands. I remember sitting at his mixing desk to hear some multichannel music, and it was so different that I just couldn't process it at the time. I was so used to stereo, that more channels threw me for a loop. Also visiting the studio with me was Alan Sircom, who upon 30 seconds of listening said, "We've got it all wrong." He was so impressed by the multichannel presentation that he referenced audiophile stereo playback as "wrong."

I mention that experience to show readers that immersive audio isn't new, and it has been done in audiophile quality for many years. In addition, Bert has been on the leading edge of sound quality for decades. Here is a snippet from his website.

"Director Bert van der Wolf is a practicing recording engineer/producer based in The Netherlands and has run his own audio recording facility since 1996. He trained in Electronics at the Higher Technical School in Enschede from 1982 to 1985, served in the army a year and after that studied and practiced Music Recording, Piano and Classical Guitar at The Royal Conservatory in The Hague, where he gained the internationally recognized Tonmeister qualification in 1990.

Bert worked for the Dutch recording companies Channel Classics from 1989 to 1996 and Kompas CD Multimedia from 1996 to 2000, making several hundred recordings for numerous international record labels. He also works as a consultant and “evangelist” for many recording studios and professional audio equipment manufacturers. Bert has been making High Resolution recordings since 1996, starting initially with the 24/96 formats and then moving on to 24/192 and DSD. He engineered the world’s first 24/192 recordings for Samsung in 1996. As a technical consultant he was responsible for the assembly and delivery of 3 first prototype 8 channel DSD recorders to Philips and worked together with their NATlab on the specifications. Hundreds of the first SACD releases that appeared in the early 2000′ have been made with these systems. Bert specializes in acoustic recording techniques and has numerous award winning recordings to his credit. In 1997 he was a co-founder of the High End Audio label Turtle Records®, and from 2008 onwards he is the sole owner of Edison Production Company BV, which harbors Turtle Records® and its spin-off brand “The Spirit of Turtle”. The latter is a merging between Turtle Records® and HQ|NORTHSTAR branded recording productions."

Auro-3D Decoding and Playback

Auro-3D is another format for immersive audio creation and playback. Auro-3D's competitors are Dolby Atmos and DTS:X. Atmos and DTS:X are object based formats, while Auro-3D is channel based. Auro's object based format is called AuroMax, but so far I haven't seen any music encoded this way and don't believe we will for the foreseeable future. Auro-3D is capable of of 9.1, 10.1, 11.1, 13.1, stereo, and binaural playback. One nice aspect of Auro-3D is that the recording is mixed into a 5.1 surround PCM file, which is then extracted into the aforementioned formats by the Auro-3D decoder. This is very similar to Atmos files appearing as 8 channel until they are decoded into 7.1.4 and beyond. Without the Auro-3D decoder, files play as more traditional 5.1 surround recordings. The decoder is what brings the height channels to life. 

Back to Bert and The Spirit of Turtle. Browsing the music available from Bert's site, one can see Auro-3D 9.1 albums encoded at 5.1+4, at 24/96. The letters and number are a bit confusing at first. 5.1 is the same 5.1 that we've known about forever. Three front speakers, two rear speakers, and a subwoofer. The +4 is four height channels to equal 9.1. In Dolby Atmos terminology this would be 5.1.4, but Auro-3D typically goes with 9.1.

The Spirit of Turtle offers quite a few Auro-3D albums for download, with new ones added frequently. The latest is Raaf Hekkema, Bach Cello Suites on vintage saxophones. Yesterday I got Camerata RCO's Bach: Goldberg Variations | String Trio in Auro-3D 9.1, and my challenge to decode and play this content from a computer began. I should note, processors such as those from Trinnov and Lyngdorf, decode Auro-3D content without an issue. Outputting this stuff bit perfectly to a processor over HDMI is all one needs. However, I like options and the ability to use DACs, and convolution for room correction, so I "must" get everything working with a computer. 

Auro Technologies offers a VST3 plugin for Mac computers only, that decodes an Auro-3D encoded file into the proper channels. For example, it takes a 5.1 (5.1+4) file and extracts the encoded height channels into a 9.1 presentation for playback. These are discrete channels, not a phantom made-up up-mix of information that wasn't there to begin with. Nothing is available for Windows at the moment. 

Now for the bad news, the Plugin costs $20 per month. That's a tough pill to swallow given that we aren't making money from its use, but rather enjoying what has been created by professionals using the Auro product. I have an email into Auro asking about a consumer version for playback only. I don't have high hopes it will come to fruition. Plus, the VST3 plugin, is only supported on a few DAW platforms, nothing close to the playback apps we use on our desktops ad music servers. 

How To Do It

For those dedicated audiophiles, like me, who look at the price and think it's peanuts compared to how much we spend on hardware, here is a guide to getting Auro-3D music decoded and played on a Mac and through a high end audio system. 

Requirements:

1. AURO-3D CTS for Music
2. Mac with Intel CPU
3. JRiver Media Center

I tested this with both JRiver Media Center 29 and Audirvana Studio. Audirvana Studio has problems with the VST3 plugin that made it crash and the plugin wasn't configurable with AS. JRiver has no such issues. 

I also tested this briefly on my Mac Mini with Apple Silicon M1 processor and had some trouble. Auro says an Intel chip is required, so I gave up quickly and moved to my MacBook Pro with an i7. I haven't completely given up on the M1 though. 

I purchased the AURO-3D CTS for Music software direly from Auro technologies here.

After installing the software and activating the license though a software iLok, don't expect a clickable icon or any audible user interface on its own. The software is only configurable from within an application such as JRiver. 

Open JRiver, go to Tools, Options, and select the Audio tab. Make sure your multichannel audio interface is selected. IN this image one can see my Ravenna 7.1.4 Atmos interface selected. This is a 12 channel interface and will work for Auro-3D.

Select DSP & output format, then select Manage Plug-ins, then select Add Driver, VST, or Winamp Plug-in...

Finding the Auro-3D plugin can be difficult, but here's a screenshot of where it's located. Macintosh HD > Library > Audio > Plug-Ins > VST3 > AURO-3D Export.vst3. Make sure you browse to the right Library folder, NOT the Library folder under your user folder.

Configure JRiver and the Auro-3D Plugin for decoding and playback.

Select Output Format on the left, then 12 Channels and No upmixing or down mixing. 

Select AURO-3D Export on the left, the the INPUT tab within the Auro plugin. Select the dropdown for Input Format within the plugin, and select Auro Enc 5.1. This means the input is a file with an encoded Auro-3D 5.1 presentation.

Then select the dropdown under MONITOR, and select Decoded. This means you want to send the decoded 9.1 audio to your output device.

Click Done in the JRiver DSP Studio.

Play an Auro 3D track, put your mouse over the little gear icon to see the audio path and make sure the audio is flowing through the two item seen here. 

Then click DSP Studio... (and keep the audio playing)

Click the INPUT tab of the AURO 3D Export plugin. You will see the Auro Enc 5.1 > 9.1 indication, and the SYNC box should be yellow.

On the OUTPUT tab, you will see the SYNC box yellow as well, and the decoded format as Auro 9.1. 

That's it. 9.1 Auro-3D audio encoded into a 5.1 FLAC file, is now being decoded and playing correctly through JRiver. 

What about playing Auro-3D and other stereo or multichannel content that shouldn't go through this Auro-3D plugin? I'm glad you asked. JRiver also includes track specific DSP configuration. Meaning, one can set a DSP preset for each track. The Auro-3D track should use the aforementioned DSP Studio configuration, while most other tracks can use another preset or nothing.  

I will get into track specific DSP settings in another article. 

That's a wrap for Auro-3D. On another note, a large truck with several crates of Wilson Audio speakers literally arrived as I was typing this article. Everything mentioned in my last update, is here! Time to get out the drill and start unpacking. I have a fun day planned. Life is good :~)