Sources - The Ultimate Guide To High End Immersive Audio

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Welcome to the sources chapter of the Ultimate Guide To High End Immersive Audio. The main table of contents can be viewed here.

Defining Sources

The term source in this guide refers to the physical component from which the music originates in one’s audio system. The source may be referred to as a music server in some circumstances, a streamer in another, a computer in another, and even a mobile device. When defining the source we must stop going upstream at some point. In this guide we stop at the originating component in the home audio system, rather than continuing upstream to a streaming service, record label, artist, guitar, strings, metal manufacturer, etc… It could get ridiculous real fast.

Immersive audio source components aren’t created equal. No source can play everything, some can play many formats, while others are very limited due to hardware or software. The limitations aren’t necessarily bad, but should be considered by those seeking an immersive system.

Here are current sources capable of playing immersive audio, in no specific order.

Computer

Identical to stereo playback scenarios, computers provide the ultimate flexibility and power for immersive audio playback, but aren’t without drawbacks.

Why use a computer for immersive audio playback? When it comes to sound quality, there currently isn’t anything that can outperform a computer based solution. The main reason is that computers have endless resources to run extremely powerful state of the art digital signal processing. I know those three words, digital signal processing, are anathema to many audiophiles, but an immersive system without DSP requires each loudspeaker be placed equidistant from the listening position at a bare minimum, never mind room interactions with eight to sixteen loudspeakers. DSP has its own chapter in our Ultimate Guide To High End Immersive Audio. For the purposes in this Sources chapter, the bottom line is that state of the art powerful DSP is objectively and subjectively better and can only be run on a computer.

Use of a computer for immersive audio also enables audiophiles to play the holy grail, discrete immersive music. To date this has been released as both ten and twelve channel 24/352.8 wav files. Technically a music server can play this as well (discussed below), but it’s a bit of a unicorn right now. Nothing else can handle these files for playback or digital signal processing.

Part of the reason audiophiles can play discrete immersive audio from a computer source, and another reason why I absolutely love using a computer for this, is the fact that computers can use Ethernet, USB, Thunderbolt, or HDMI as outputs. HDMI is quite limited, but the others are extremely flexible.

As an audiophile I’ve used a computer for stereo playback using USB and Ethernet “forever.” It’s a logical extension to use these interfaces, and take advantage of their benefits, for immersive audio. Computers can use AES67, Ravenna, Dante, and AVB over Ethernet to send sixteen channels of music without a hiccup. Only Ravenna is currently capable of sending immersive DXD over Ethernet. A Thunderbolt interface is also capable of extreme sample rates and high channel counts.

Note: Ravenna is extremely powerful and designed for low latency audio from the ground up. It is used to record anywhere from one to one hundred musicians at a time, when no second takes are possible. Many of the recordings we listen to on a daily basis were done using Ravenna. Similar to Ravenna is Dante. Dante has a larger install base in professional audio and is used to run many live concerts around the world. Ravenna and Dante software, when installed on a computer, appear as an audio interface just like a USB DAC, to which audio can be directed. The same items such as exclusive mode, integer mode, etc… apply to these interfaces.

Another benefit of using a computer or music server for immersive audio playback is that a dedicated video screen is not required to play music. I’m anti-video, pro-audio, and will not use a screen in my listening room. No judgement toward those who use and love them, but it’s just not my thing. I can control my computer with an iPad or iPhone from my listening chair, or use my laptop as needed.

Recapping the WHY of computer use for immersive audio, we have powerful state of the art DSP, support for the highest sample rates, flexible audio interfaces, and no video display requirement.

What about the negative aspects of using a computer for immersive audio playback? The main negative aspect is complexity. Without guides detailing how to do it (coming soon), many people struggle to figure it out. It’s not as simple as connecting an HDMI cable from an Apple TV to a receiver and clicking the remote. Computers also require maintenance in the form of updates and some troubleshooting when things just don’t work. It happens. I look at this like a high performance F1 car versus a Toyota Camry. The F1 car can deliver performance on a crazy level, but requires some knowledge to operate and maintain. The Camry is turn-key and will run forever, but isn’t designed for performance.

When it comes to using a computer to play immersive audio, I have a couple recommended solutions, based on experience and research. Listeners are certain welcome to do their own research and try to bend other solutions into conformity, and I enjoy reading about that stuff, but for those looking to skip to the front of the line, here are some specifics.

My main immersive audio computer is a MacBook Pro with an M2 Pro chip, 16GB of RAM, a 1 TB drive, running macOS Sonoma. Macs are the only computer based solution capable of playing Dolby Atmos music from a streaming service and Apple Music is that service. These two points can’t be overstated. A Mac with Apple Music is the only combination capable of streaming Dolby Atmos music to/from a computer.

Newer Macs can play Atmos out of their speakers and reproduce a neat spatial audio experience, but for our audiophile purposes when I talk about playing Atmos from a computer I’m talking about outputting that audio to a high end system. Neither Amazon Music nor Tidal offer Atmos output via their desktop applications. In addition, no music services offer Atmos streaming on Windows or via integration with applications such as Roon, Audirvana, JRiver, etc…

When music is streamed from Apple Music to a Mac, it’s processed by the licensed Dolby Atmos (DD+) decoder in macOS, then output as a PCM stream to a DAC. This is a big deal. Atmos requires decoding. The fact that it can be decoded on the Mac, opens up a world of both hardware and software improvements. I route the audio to state of the art digital signal processing, then output it to Merging Technologies hardware for conversion to analog. I wouldn’t route my high end stereo signal through a receiver / processor, and I don’t do that with immersive audio either.

In addition to playing lossy Atmos music from Apple Music, Macs are capable of playing lossless TrueHD Atmos content from ripped Blu-ray Discs or purchased MKV downloads. Playback isn’t as easy as it is with Apple Music because no computer operating system has a built-in TrueHD decoder. The is where things get a little complicated for the less tech savvy.

The TrueHD Atmos content can be extracted from the aforementioned legal sources, and played using the Dolby Reference Player as it has a TrueHD decoder. However, the Reference Player is more of a laboratory tool with a primitive interface. It certainly works, but we have better options. Using the Dolby Reference Player on a Windows computer, combined with software called Music Media Helper, enables us to convert the TrueHD Atmos music into decoded WAV files, for playback in any application that supports the number of channels needed.

I convert my TrueHD MKV files into 12 channel WAV files on a Windows PC, then use my MacBook Pro to play them in JRiver and Audirvana.

Note: I have no interest in circumventing the commercial channels or advocating for anything illegal. I purchased the Dolby Reference Player for $400. It’s worth every penny. I wish Dolby would make this easier, as I know there are tons of computer audiophiles willing to hand over their money for a more consumer friendly TrueHD decoder that works on a computer. Or, the ultimate solution is for Dolby to license a TrueHD decoder to Audirvana or Roon, so we can just play these files like we play our two channel stereo albums.

A quick recap of my MacBook Pro based immersive audio solution.

Streaming - I stream from Apple Music, macOS decodes the Atmos stream automatically into standard PCs audio, I output the audio to Hang Loose Convolver for state of the art room correction (65,000 taps), then  on to my Merging Technologies hardware via Ravenna (over Ethernet).

Local Playback - I convert the lossless TrueHD Atmos albums on a Windows PC to 12 channel WAV files, then store them on my QNAP NAS. I use Audirvana or JRiver to output the files to Hang Loose Convolver for state of the art room correction (65,000 taps), then  on to my Merging Technologies hardware via Ravenna (over Ethernet).

In a Mac only environment, I either use the Dolby Reference Player to decode TrueHD and output to Hang Loose Convolver, or I’ve captured the PCs output of the DRP to 12 channel WAV files for playback in the app of my choice. The Windows route is preferred.

In a perfect world, Audirvana, JRiver, Roon, etc… could decode the Atmos music from both streaming and local sources. A little encouragement from immersive audio fans couldn’t hurt (contact the app companies and Dolby, so they realize there’s need and demand).

Note: I also purchased the Dolby Atmos Renderer application for playing master ADM files. These are rarely released, but to date I’ve purchased a couple. The Renderer enables the listener to not only play the ADM master file, but also output (re-render) the file to a standard WAV file that can be played in Audirvana or JRiver, with all of the objects and channel information correctly played.

Windows works very well for immersive audio, with one exception, streaming. No streaming service offers Atmos music on the Windows platform. Given that the vast majority of Atmos music is still only available via streaming, this is a major showstopper for many listeners.

I use Windows in my immersive audio system for local playback and file / format conversions. My MacBook handles local playback just as well, but I like to have Windows, so I know it and can test anything I need.

One item to consider is that Windows currently supports using the Auro-3D decoding plugin. Yes, macOS is officially supported as well, but the plugin doesn’t work on Apple Silicon. In other words, it doesn’t work on any Mac available from Apple today. Auro files are available on Blu-ray and via purchased downloads from a few labels. I’ve use the decoder plugin and gotten it to work decently on Windows and an Intel based Mac. Consumer applications such as Audirvana and JRiver aren’t officially supported, and the company appears to have zero desire to change this. I’ve written about how to get it working, but I no longer have the $20 per month subscription required just to play these files. Almost everything available in Auro-3D is also available in Atmos, so I select Atmos when purchasing downloads.

Using Windows as a tool rather than source for immersive audio playback, is what I do frequently. With the purchased Dolby Reference Player and Music Media helper installed, I use it to decode TrueHD Atmos albums into WAV files playable in any app that supports 12 channels. If listeners convert to 5.1.2, eight channel Atmos files, then FLAC can be used as well as Roon.

A quick recap of my Windows based immersive audio solution.

Streaming - None. No services support streaming Atmos music on Windows.

Local Playback - I convert the lossless TrueHD Atmos albums to 12 channel WAV files, then store them on my QNAP NAS. I use Audirvana or JRiver to output the files to Hang Loose Convolver for state of the art room correction (65,000 taps), then  on to my Merging Technologies hardware via Ravenna (over Ethernet). Merging’s Ravenna driver on Windows is much more flexible and capable than the macOS driver.

What about Linux? Ideally all the required apps would work on Linux, but they don’t. I’m a huge fan one Linux and believe it’s the only way to get something to work like a toaster. By that I mean, simple to operate and works every time. Example, place bread in a toaster, push down the lever, wait, out comes toast. High end music servers started on macOS and Windows before moving to Linux. Eventually we’ll get toaster-like Linux solutions for immersive audio, but I’m not holding my breath. I love what I hear and wouldn’t wait a day longer to experience this much enjoyment.

There are pros, cons, and considerations for going the immersive computer route. Each listener must weigh the importance of features, ease of use, and sound quality, before deciding if this is a good route for him/her. Just like when two channel high resolution audio came on the market, consumers needed to understand themselves just as much as the options for playback, before selecting a route. Listeners with a computer source for two channel audio, will likely want the same setup for immersive audio. Listeners who use a music server will want to think about why they went that route sound quality, ease of use, etc…) and weigh the immersive options against that reasoning.

Streamer

By far the easiest way to play immersive audio is from a source that I’ll just call a streamer. These are capable of outputting both lossy streaming Atmos and lossless Atmos and Auro-3D audio. Streamers don’t decode the immersive audio, they deliver it perfectly to a processor or receiver capable of decoding the music.

Streamers can function like an appliance with both hardware and software contained in one unit, and a simple user interface. There’s no real maintenance or installation of applications outside of the platform’s App Store, and when these units are powered on, they just work. With very few pieces to the puzzle, very few things can go wrong.

On the other hand, these streamers require a display. Some of them require it often, others not so often. I wouldn’t use a streamer without a display at the ready because sooner or later a message will appear on the screen and the listener will need to read it and act upon it. For many audiophiles this is a non-issue as they have screens in their rooms already. For me, screens are the antithesis of a great music listening experience, plus I hate looking at them.

When it comes to sound quality, these streamers output via HDMI and are dependent on the quality of the decoding device. This usually means a receiver or processor that is limited in DSP capabilities and flexibility. The continuum here is large, in that some processors are very good (Trinnov), while other more big box style receivers have terrible DSP. It’s expensive to do powerful DSP in hardware, which is why most products have the bare minimum. Again, more details will be available in the DSP chapter.

As I said in the computer section, no source can play everything. The immersive content a streamer can’t play is discrete immersive DXD music. The sample rates are just too high for these devices and the attached processors. Given that Atmos is 24/48 and Auro-3D is up through 24/96, streamers are a good match for these formats.

One device that’s coming soon, that will enable use of a streamer while opening up more DSP options is the Arvus H1-D. This will accept the HDMI signal from a streamer and output it over a network via AES67. Once the decoded music is output to the network, it’s regular PCM and can be routed to computer or DSP component over the network for processing. This will be a great addition to one’s immersive lineup.

Specifics - Streamers that come to mind right away are AppleTV, NVIDIA Shield, and Amazon FireStick. There are others and will continue to be more. One nice thing about these streamers is that they support streaming Atmos from more music services such as Apple Music, Tidal, and Amazon. However, I’ve been in the room when Tidal Atmos played through a Shield put out tweeter melting static. I’ve never seen this happen with an AppleTV and Apple Music, the quality control just seems much better.

Streaming immersive music from services through an AppleTV, NVIDIA Shield, or FireStick gets the listener a lossy Atmos version, just like using a computer. The big benefit of a device like the Shield is that it can easily output TrueHD Atmos from local files, increasing the sound quality immensely.

A Shield with the Kodi application and either a USB stick or NAS drive, is a fantastic combination for an immersive source (article here). The USB stick can hold many MKV albums (Atmos, Auro, and others) and Kodi offers the user interface from either a display or mobile phone / tablet. When I eventually get an Arvus H1-D, I will pair it with an NVIDIA Shield and the Kodi app because I believe this is the best solution for audiophiles. Plus, the cost of a Shield TV Pro is peanuts at $199.

Another streamer that must be mentioned is Sonos. However, Sonos is a different animal and will receive its own chapter in this guide. It’s possible to play Atmos from Apple Music and Amazon via Sonos, using a couple different speaker configurations. This is perhaps the ultimate for ease of use.

Recapping immersive audio via streamers. This is a very easy way to get into the immersive game. For many, this will be as far as they ever want to take it, and they’ll be very happy with the sound quality. Streamers offer a solution for the person who just wants to sit down, select an album, and listen. Streamers aren’t the most flexible, high performance, or feature rich solutions, but again, think about a race car versus a Camry. Knowing oneself as well as the options, goes along way to selecting the correction solution. There are no wrong answers.

Music Server

Music servers, as in the music servers audiophiles know and love from a number of manufacturers. These are computers, but not like our every day computers. Many run Linux and work like an appliance with fantastic user interfaces and hooks into streaming services and library storage. These servers were only in our dreams when high resolution audio first became available, but now they are everywhere. Life is good for stereo playback.

When it comes to using a music server for immersive audio, I think about unicorns. This is because I currently do it, but it isn’t an advertised or supported feature. Getting it to work required some customization. Here are the considerations.

Immersive audio requires up through sixteen channels of playback. Many music servers can be ruled out by this requirement. These servers are limited to traditional two channel AES, S/PDIF, or Toslink interfaces. Music servers supporting output via USB could technically get into the immersive game, but must be careful with discrete DXD because 8-16 channels of 24/352.8 requires serious bandwidth with which older USB interfaces will struggle. Keep in mind also that these music servers don’t support onboard DSP for room correction in the time and frequency domains.

We are left with the very few music servers that support outputting audio over Ethernet, specifically Ravenna. Aurender has supported Ravenna for many years. Using an Aurender and the Conductor iPadOS app, I can output 7.1.4 twelve channel WAV files (converted on my Windows PC from blu-ray rips or purchased downloads) to my Mac for DSP using Hang Loose Convolver, or directly to my Merging hardware and its built-in SoundID Reference room correction. I much prefer Hang Loose Convolver because of the endless power and capabilities on my Mac.

The bottom line here is that it’s entirely possible to play immersive audio, even 12 or more channels of discrete DXD, with a music server. The only hangup is that it’s not fully supported by the manufacturers yet. A few nudges in the right direction may help though.

Ideally, a high end music server would stream and decode Atmos from Tidal/Apple Music/Amazon, decode TrueHD MKV albums, and feature a convolution engine for state of the art room correction. That’s a dream for sure, but in the meantime a server that can play 12 channel WAV files and run convolution before outputting over Ethernet to a DAC would be a great start. Heck, even the new Kii Seven speakers accept Dante audio over Ethernet and could accept a stream right from a music server. A potentially slick solution.

Mobile Device

The last source of immersive audio is a mobile device. Those seeking the utmost in sound quality can bypass this section entirely. Mobile devices such as an iPhone, iPad, and Android tablet can stream Atmos music. My iOS, iPadOS, and Samsung Android tablets all stream Atmos from Apple Music. The issue is this music is locked into a stereo or binaural mix.

I actually listen to Atmos via Apple Music on my iPhone quite a bit and have come to appreciate the differences between it and the standard two channel stereo mix.

Similar to Robert Durst on the finale episode of The Jinx, the he said nobody tells the whole truth, Apple’s published requirements for Atmos playback are accurate but don’t tell the whole story. Apple would like everyone to believe its own headphones and EarPods are required for Atmos playback. The whole truth is that any headphones can reproduce Atmos from Apple Music, Tidal, and Amazon. The only feature that currently requires Apple branded head/earphones is head tracking. My all analog Alclaire electrostatic in ear monitors don’t have a way to feeding my head position back my iPhone, so I just get the straight Atmos music feed. Not a show stopper for me, and in fact a preferable way to listen.

A discussion of immersive audio and mobile devices should also cover AirPlay and Google Cast. Both of these are currently in the Wild West category. I haven’t been able to get any Atmos from any app to work over AirPlay (1 or 2) or Chromecast. Apple says it works with an iPhone and HomePod, but not a HomePod Mini, despite the Atmos option being available for my HomePod Mini. I have friends with HomePods who successfully play Atmos via AirPlay 2, and I’ll take their word for it.

None of my HiFi devices that support AirPlay 2 also support Atmos, not even the two channel of binaural mix.

Sources Wrap Up

Immersive audio sources are in a similar position as two channel sources were when high resolution audio first became available. A computer was and is the most flexible and powerful option for playback. Going hand in hand with that is also complexity. No different from many other categories of products in our lives. A Ferrari FXXK isn’t as easy to use as a Honda Accord, but potential buyers should understand their own requirements as well as the pros and cons of each before jumping in the driver’s seat. The same is true of immersive audio sources.

In audiophile terms, those who use HQPlayer and NAA to upsample and select filters and modulators are a different group from those using Roon with a Nucleus connected to a DAC via USB. Just like the real world, there are people using both and most of us are somewhere in the middle.

If one is only interested in streaming Atmos music and already has processor and display, then an AppleTV is a super simple option. Those who want to take it to the next level and play TrueHD Atmos will want to consider a very high end processor with a streamer or computer based source. Crazy audiophiles such as myself who want to play discrete immersive audio with twelve channels of DXD, and use absolute state of the art DSP/ room correction, will need to use a computer as a source, there’s no way around it.

The fact that 99% of immersive audio needs to be decoded, should remain top of mind. Audiophiles are used to FLAC and WAV, straight PCM files that will play on nearly anything. Immersive audio is usually Dolby Digital Plus or TrueHD Dolby Atmos and both require separate decoders. Decoding DD+ can be done on a Mac with the built-in DD+ decoder, but not on any other source. Decoding TrueHD requires some hoops on a computer, but is successfully done every day by many of us.

Offloading the decoding to another device by using a streamer, or computer with HDMI output for that matter, is an easier route with its own pros/cons. There are no right or wrong answers with immersive source selections. It’s all about using the right tool for the job.

Further Reading

• Playing TrueHD Atmos Music Downloads & Blu-ray Rips The Easy Way
• How To Decode and Play Dolby TrueHD Atmos on Windows and macOS
• The Digital Side Of My Immersive Atmos Music System
• Lossless TrueHD Atmos Just Got Much Easier
• An Audiophile’s Journey into Immersive Audio

• All Audiophile Style immersive audio articles can be fund here (link)

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