Article: Thoughts On Immersive Audio

[The Computer Audiophile]

13 minutes ago, bbosler said:

 

IMHO it is a horrible experience on Apple TV with video. The camera changes every 2 -6 seconds. While the sound remains fixed in space the video jumps around constantly

 

here's the soloist for 5 seconds

jump to a closeup of a violinist for 2 seconds

jump to a wide angle of the conductor and orchestra for 3 seconds

back to the soloist for 4 seconds

camera slowly swoops in from the back of the orchestra until all you see is the conductor

closeup of the violins for a few seconds

closeup of the percussionist for a second

closeup of the flautist for 3 seconds

 

 

and on and on for an hour or more ???? no way in hell I can sit through that.. It is a HORRIBLE experience

 

 

 

 

This is definitely an issue. Directors of photography need to figure out how to show this so it works with the audio. The audio is so good at enabling us to locate instruments and hear reverb, that I’m not sure how video can make this work. It seems like a close up on the violinist would require audio switch to that perspective. Yuck!

[bbosler]

4 hours ago, The Computer Audiophile said:

Directors of photography need to figure out how to show this so it works with the audio. 

What works for rock or jazz with a small group simply doesn’t for a symphony orchestra. I just watched Robert Plant at Glastonbury on Qello.
 

Superb… they cut to whoever had the lead.. one of the guitar players, Plant, whoever and it all made sense. For one, they didn’t change cameras every few seconds like a 1980’s MTV video. And there really is no sense of soundstage at a a rock concert, just a huge wall of sound so zooming in on the lead guitar is not distracting 

 

but on this Berlin Philharmonic it was like the director is ADD jumping all over the orchestra changing cameras every few seconds just because he or she can. Would much prefer a fixed location for the camera just like the microphones are fixed in place.. like the experience you have when you go to the symphony 

 

thanks for tolerating my little rant

 

BTW Qello is a lot of fun if you have video capability. Watching Miles Davis and Quincy Jones at Montreux doing Gil Evans arrangements… very tasty 

[Geoffrey Armstrong]

A quick question; is it possible to decode Spatial audio streams from Apple's music app to 6 Channels, using BlackHole 16Ch version, and feed the result to HQPlayer with BackHole 16Channel, set as the input?

 

Apologies in advance if I misunderstood previous discussion on this in these articles; but I got the impression, it should be possible to decode these Spatial streams "on the fly" and feed them into HQPlayer to play though my traditional 5.1 MCH system. All I get though is two channel stereo passed through.

 

Thanks

[The Computer Audiophile]

4 hours ago, Geoffrey Armstrong said:

A quick question; is it possible to decode Spatial audio streams from Apple's music app to 6 Channels, using BlackHole 16Ch version, and feed the result to HQPlayer with BackHole 16Channel, set as the input?

 

Apologies in advance if I misunderstood previous discussion on this in these articles; but I got the impression, it should be possible to decode these Spatial streams "on the fly" and feed them into HQPlayer to play though my traditional 5.1 MCH system. All I get though is two channel stereo passed through.

 

Thanks

I believe @El Guapo is doing something similar, or knows if this is possible. 
 

I haven’t tried it this way, but can give it a shot later. 

[Geoffrey Armstrong]

Thanks Chris. That would certainly widen our choices of Immersive/MCH we could play this way. Although we’d obviously prefer it to be lossless.

 

I’m wondering if MacOS needs to “see” an AVReceiver connected via HDMI, before it will decode all 6+ channels?

[The Computer Audiophile]

5 minutes ago, Geoffrey Armstrong said:

Thanks Chris. That would certainly widen our choices of Immersive/MCH we could play this way. Although we’d obviously prefer it to be lossless.

 

I’m wondering if MacOS needs to “see” an AVReceiver connected via HDMI, before it will decode all 6+ channels?

My guess is you need to create an aggregate device and setup the device as a 5.1.2 layout in Audio MIDI. Set Apple Music to play Atmos “automatic” (not off or on always), and it will send 8 channels. The height channels will just be ignored if you have a 5.1 system. 

[The Computer Audiophile]

10 minutes ago, Geoffrey Armstrong said:

Thanks Chris. That would certainly widen our choices of Immersive/MCH we could play this way. Although we’d obviously prefer it to be lossless.

 

I’m wondering if MacOS needs to “see” an AVReceiver connected via HDMI, before it will decode all 6+ channels?

You can see some of this config, in this conversation. 
 

 

[PeterG]

On 7/5/2022 at 1:37 AM, bbosler said:

like the director is ADD 

Definitely not PC of us to use this term, but I agree 100%.  Further, this is a problem that plagues a huge number music documentaries.  They wax eloquent for 10 minutes about a certain song being of earth-shaking importance, and then play only 20-30% of the song.  Somehow, they don't think we can enjoy the whole 5 minutes of the actual song?

[wisechoice]

20 hours ago, Geoffrey Armstrong said:

A quick question; is it possible to decode Spatial audio streams from Apple's music app to 6 Channels, using BlackHole 16Ch version, and feed the result to HQPlayer with BackHole 16Channel, set as the input?

 

Apologies in advance if I misunderstood previous discussion on this in these articles; but I got the impression, it should be possible to decode these Spatial streams "on the fly" and feed them into HQPlayer to play though my traditional 5.1 MCH system. All I get though is two channel stereo passed through.

 

Thanks

Yes, this is certainly possible and works well. You need to set the channel layout for Blackhole in Audio MIDI Setup with the "Configure Speakers" button and then Apple Music will recognize it appropriately and output the correct number of channels. Spatial audio in Apple Music preferences should be set to "automatic" in Monterey, and "always on" in Big Sur. In HQPlayer, you then need to configure the input backend as having 6 or more channels for 5.1, and set the source to "audio:default/48000/6" or /8 etc for 5.1.2 and higher.

[wisechoice]

15 hours ago, The Computer Audiophile said:

My guess is you need to create an aggregate device and setup the device as a 5.1.2 layout in Audio MIDI. Set Apple Music to play Atmos “automatic” (not off or on always), and it will send 8 channels. The height channels will just be ignored if you have a 5.1 system. 

Creating an aggregate device is not necessary if the output is Blackhole 16ch, and shouldn't be necessary if the hardware output device already has sufficient outputs. However, I've noticed that getting more than 6 channels is spotty when outputting directly to at least some interfaces (in my case the Digiface USB), whereas Blackhole 16ch as the intermediary works just fine.

[wisechoice]

On 7/4/2022 at 8:49 PM, bbosler said:

 

IMHO it is a horrible experience on Apple TV with video. The camera changes every 2 -6 seconds. While the sound remains fixed in space the video jumps around constantly

 

here's the soloist for 5 seconds

jump to a closeup of a violinist for 2 seconds

jump to a wide angle of the conductor and orchestra for 3 seconds

back to the soloist for 4 seconds

camera slowly swoops in from the back of the orchestra until all you see is the conductor

closeup of the violins for a few seconds

closeup of the percussionist for a second

closeup of the flautist for 3 seconds

 

 

and on and on for an hour or more ???? no way in hell I can sit through that.. It is a HORRIBLE experience

 

 

 

 

 

I re-activated my subscription the other day after reading this article, and was very excited to start listening in Atmos. My experience of the video was a bit different. I found that the editing between angles seemed to anticipate the music relatively well, so that when an instrument or group had the focus in the music, the video switched focus along with it. However, this was sometimes to the detriment of being able to choose what to focus on in the music myself, and so there were times when it was a distraction. However, closing ones eyes and just listening, as you might do at a live performance, is still always an option. And if you're able to turn off the screen without interrupting the sound, as I'm able to do from my Mac mini, then the listening experience itself is still the same.

 

On 7/4/2022 at 9:06 PM, The Computer Audiophile said:

This is definitely an issue. Directors of photography need to figure out how to show this so it works with the audio. The audio is so good at enabling us to locate instruments and hear reverb, that I’m not sure how video can make this work. It seems like a close up on the violinist would require audio switch to that perspective. Yuck!

 

As a film editor, I can assure you that the responsibility lies mainly with our craft, and with the director and whoever else is responsible for the video as a whole. Directors of photography are responsible for making the shot look as good as it can. After that, the choices are up to other people on the team.

And as an editor, I can confirm that multi-channel editing requires restraint. Even more so when there are so many camera angles to choose from, as there seem to be with these Berliner Philharmoniker productions. 

[Geoffrey Armstrong]

2 hours ago, wisechoice said:

Creating an aggregate device is not necessary if the output is Blackhole 16ch, and shouldn't be necessary if the hardware output device already has sufficient outputs. However, I've noticed that getting more than 6 channels is spotty when outputting directly to at least some interfaces (in my case the Digiface USB), whereas Blackhole 16ch as the intermediary works just fine.

Thanks so much to both Chris and wisechoice. Yes, I confirm it's now working. The references to "aggregate devices", Anubis, VAD; etc, etc. all went over my head a bit as I'm not using Merging devices or Ravenna.

 

I don't know where exactly I was going wrong, as what I had tried appears to be in line with your advice. I have an old Exasound E28, connected to my Mac via USB. I set this as ATMOS 5.1.2 Surround device in Audio Midi Setup, set the default output device as BlackHole 16CH, set that as the input to HQPlayer, which is playing out to the Exasound set as an 8 channel device. Finally I chose the audio:default/48000/2 output option; but then edited the "/2" to replace it with "/6".

 

I'm doing this on my M1 Mac Air. Previously I was trying it on my Intel 2018 Mac Mini. So I don't know if the Intel Mac Mini (also running Monterey) is capable of decoding Atmos, or if it needs to be an M1. I also can't remember if I chose Atmos as "Automatic" (the correct option) in Apple Music app or "Always", which would have been wrong.

 

I also remember I chose standard 5.1 Surround in Audio Mini set-up rather than the Atmos option.

 

Will check tonight or tomorrow the Intel Mac.

 

Anyway, I'm now looking forward to experiencing all that Spatial content decoded to my 5.1 system.

 

👍👍👍

[El Guapo]

On 7/9/2022 at 11:56 PM, Geoffrey Armstrong said:

is it possible to decode Spatial audio streams from Apple's music app to 6 Channels, using BlackHole 16Ch version, and feed the result to HQPlayer with BackHole 16Channel, set as the input?

Yes confirmed. I've been using this way since Apple started to streaming Atmos music...

[Roy Boy]

My question is around the incremental benefit of the .4 overhead channels if you are coming from a 7.1 system. I have a hybrid 2-channel/ 7.1 system where I use a Manley Skipjack to switch my LR channels from stereo to 7.1. I have been streaming mch dsd and pcm from my NAS via Oppo 103D then HDMI to my Integra DHC 80.3.  I just discovered the Dolby Atmos streaming from Apple Music via Apple TV 4K that works in my 7.1 System. Tidal Atmos does not work as my processor is not Atmos capable.

  It is a non-trivial move to add at the overhead channels. Need an upgraded processor, additional amp channels, overhead speakers and the “fun” of cutting holes in the ceiling and running speaker cables up the wall and over the ceiling.

  So my question is for those that have been streaming the Atmos content on a 5.1 or 7.1 system and added the overhead channels. What benefits did you see?  Alternatively if you have a 7.1.4 system what do you lose if your turn off the overhead channels? Thanks for your insights. This is fun exploring this new content. I am just trying to make informed choices..

 

My System

  SPEAKERS - Green Mountain Audio C-3 HX (LR), Green Mountain Vortex (center), M&k SS-150 surround and rear, 2 x Seaton submersive subs

AMPs - Code No.8, EAD PM 1000

STREAMER - Lumin A1

Processsor - Integra DHC 80.3

Stereo Mode Sub crossover - DBX PA II

 

BTW..have an analog front end I have ripping vinyl to 24/352 via RME ADI-2 Pro and VinylStudio to stream. That is a who other subject

 

 

[The Computer Audiophile]

10 minutes ago, Roy Boy said:

My question is around the incremental benefit of the .4 overhead channels if you are coming from a 7.1 system. I have a hybrid 2-channel/ 7.1 system where I use a Manley Skipjack to switch my LR channels from stereo to 7.1. I have been streaming mch dsd and pcm from my NAS via Oppo 103D then HDMI to my Integra DHC 80.3.  I just discovered the Dolby Atmos streaming from Apple Music via Apple TV 4K that works in my 7.1 System. Tidal Atmos does not work as my processor is not Atmos capable.

  It is a non-trivial move to add at the overhead channels. Need an upgraded processor, additional amp channels, overhead speakers and the “fun” of cutting holes in the ceiling and running speaker cables up the wall and over the ceiling.

  So my question is for those that have been streaming the Atmos content on a 5.1 or 7.1 system and added the overhead channels. What benefits did you see?  Alternatively if you have a 7.1.4 system what do you lose if your turn off the overhead channels? Thanks for your insights. This is fun exploring this new content. I am just trying to make informed choices..

 

My System

  SPEAKERS - Green Mountain Audio C-3 HX (LR), Green Mountain Vortex (center), M&k SS-150 surround and rear, 2 x Seaton submersive subs

AMPs - Code No.8, EAD PM 1000

STREAMER - Lumin A1

Processsor - Integra DHC 80.3

Stereo Mode Sub crossover - DBX PA II

 

BTW..have an analog front end I have ripping vinyl to 24/352 via RME ADI-2 Pro and VinylStudio to stream. That is a who other subject

 

 

Hi @Roy Boy it all comes down to the music and mix. Some don't use the height channel very much, while others use all of them extensively. 

[Geoffrey Armstrong]

I have been spending the last week listening to Immersive/Multi-Channel sources through my traditional 5.1 MCH system and here are my impressions so far.

 

First off the MCH part of the system is a kind of “icing on the cake” add on to my two channel system. I put it together with both music and Home Theatre in mind; but have only listened occasionally to multi-channel music and movies through it.

 

It is by no means a dedicated purpose built Immersive system, such as Chris’s. Mine is a hybrid, consisting of a pair of Avantgarde Trio horns with a pair of the same company’s Short Basshorns. The Multi-channel part consists of one Magnepan center channel and two Magnepan rear channel speakers. The latter rest flat against the wall when not in use, and are swung out to be perpendicular to the wall for listening. So the Multi-Channel part is quite tidy and discrete.

 

I figured that, at least the Magnepan have a speed and transparency which can approach the Trios in that regard, even though they can’t match the Trios on dynamics (perhaps less important, at least for the rears).

 

IMO it actually does work quite well as a way of augmenting the main Trio system.

 

The Magnepan centre channel speaker is placed much higher than normal for a centre speaker. The reason for that is, I use a front projection system with a JVC projector beaming to a Stuart Filmscreen electric tensioned screen. Immediately behind the screen are full length windows and behind those on the outside are electric shutters. So the room can be completely darkened for watching movies. I couldn’t place the center channel either below or behind the screen so it sits way up, above the screen in an especially constructed false wall, with a cut out for the speaker. The speaker is angled down slightly towards the listening position.

 

In this room with 3 meter high ceilings, the sound from the Trio system alone has exaggerated height. I know it’s not exactly correct; but I enjoy it. Think of it as a kind of guilty indulgence. I figure, if I were to sit fairly close to a stage, which I like to do, the artists would be performing on a stage raised above me. So in that sense it does kind of correlate to real life.

 

The exaggerated height presentation of the Trio system alone in this room, often places the main voices and instruments in a position, which coincides quite closely, with the mute centre channel speaker. So to have those voices emanating from that position when the centre channel is playing, doesn’t seem out of place to me.

 

What is crucial though is the correct channel blending for MCH sources. By that I mean, the relative gain of the centre speaker compared to the main LF, RF speakers. If the center speaker is too strong compared to the main speakers, those voices will sound disembodied and coming from the rafters. Either lowering the gain on the center speaker or raising the volume on the main speakers, usually allows me to achieve a balance between the center and mains that satisfies me.

 

The same can be said of the main speakers in relation to the two rear speakers. Here also, the blend of the two rears with the two front mains is crucial to my enjoyment of Immersive/MCH sources. With the right blend on the right sources, the results can be very convincing indeed. I believe, more convincing than can be achieved with a two channel system alone. Still I have my reservations. At least on this compromised MCH system.

 

Anyway, Chris’s articles on the subject have inspired me to dust off my old MCH components and give this system more of a serious listen.The addition of Apple’s Spatial/Atmos streams have provided further incentive.

 

To complete the system description, for the MCH system all channels are fed by an old Exasound E28, which has 8 channel outputs. The two main channels are driven by Class D NCore mono-blocks, the center channel by a Class D Mono amp from Nuforce, providing 160w, and the two rear channels are driven by an integrated amp from Crayon audio, providing 190wpc.

 

So I can vary the volume of the rear speakers with the integrated amp’s volume, as well as apply channel gain adjustments in software.

 

The center channel can only be controlled with the Exasound’s volume slider and other software gain settings (in my case using HQPlayer).

 

I’ve played with this system on and off over the years, and already discovered the settings that work best for me when it comes to channel blending for rippped MCH SACDs and DVD-As. There is, of course, quite a lot of variation from recording to recording. As there is with two channels sources. Though, obviously the situation becomes far more complicated with Immersive/MCH.

 

When it comes to the sound, what I find myself enjoying the most is a more subtle multi-channel mix. By that what I mean is a mix which doesn’t place particular intruments/voices exclusively in the rear channels.

 

We all know the rear’s can be used effectively for audience sounds in a live concert and to capture the natural reverberance of instruments being played on the main stage, as the sounds bounce off the halls rear and side walls.

 

What I enjoy most, I believe, is not exactly or not just, this reverb or echo off the walls; but rather when the sound of an instrument appears to be shared between the mains (or one of the mains) and the corresponding rear speaker(s), in a way that causes the sound of that instrument to reach our further into the room and closer to me. This will vary naturally, depending obviously, on how loud the instrument is being played at any given time, and by movements of the musicians and their instruments.

 

By “channel blending”, I can hit on what, for me, is the most convincing presentation. Too strong from the rear and I might just increase the volume from the mains a little (the easiest for me to do), or the opposite when the rears seem barely audible.

 

If the mixing engineer has exclusively placed an instrument in one of the rear channels though, nothing can be done! This just never sounds natural to me. It’s always an effect; an effect that can be fun, depending on the music; but I’d rather it was used sparingly, if at all.

 

Perhaps the problem is one of perception. If someone has splashed out on an Immersive/MCH system, they want to hear those rears, otherwise what’s the point. I don’t want to hear them as separate sources though.

 

Just as us two channel guys want our speakers to “disappear” as the sources of the sound, so it should be for the rear channels IMO.

 

The situation with the center channel is similar; but a little different, in my view. Here it makes perfect sense for a main instrument/voice to be prominently placed in the center channel. Again, though this has to “blend” nicely with the mains, so that some of that voice/instrument is also being reproduced by the mains. I would say that the center channel are to the mains, what the mains should be to the rear speakers. Although of course, the center channel may also have this relationship with the rears. It’s all about natural sound propagation into the room. So, again, the instruments should (at times anyway) appear to reach out towards you/jump out at you, as they do in a live venue.

 

A really great two channel system might be able to achieve the same thing. From listening over the last week though, I’m coming around to the view, that a two channel system would struggle to achieve this as well as a decent MCH system (even one as compromised as mine). Reviews are full of descriptions of two channel gear that can convey the three dimensionality of instruments. With an Immersive/MCH system, depending on the mix, this effect of instruments reaching towards you, must have a dimensional aspect. They gain in dimensions, I’m sure, at the same time as they reach out into the room. Again though, as I’ve tried to describe, this is all varying with time and the actions of the musicians. Too often, descriptions in reviews discussing the “dimensional” aspect, give the impression of an object fixed in space with fixed dimensions. Not something which is constantly varying with time; etc. Perhaps this apparent fixedness of the dimensions comes from the limitations of two channel systems?

 

Whether an Immersive/MCH system is correctly propogating the intruments into your room, will be very much dependant on the decisions of the mixing engineer.

 

I’m certainly no musical snob; but I would say, in general, the more serious the music is considered to be, the more the engineers appear to take the approach of natural sound propogation. The less serious the music may be considered, the more liberties the engineers might be tempted to make with creative use of the channels.

 

Most of the ripped SACDs I have are of classical and jazz, and with most of these a pretty impressive job has been done in the mixing stage in these respects.

 

Over the last week though, I’ve been mainly listening to Apple’s Atmos Spatial streams. So I will take some examples from those.

 

Apple has “Spatial” playlists, each one given a distinct colour for a particular genre of music.

 

As I’m a big jazz fan, I’ll start with an example from the Jazz Spatial list:

 

Tanya from Dexter Gordon’s One Flight Up, sounds to me like a great example of how it should be done. At times the horns reach out towards me in the way I’ve described, and occasionally a thwack on the drum or a rimshot can bounce off the back wall. It’s a good one for me in getting the balance between the rears and mains right, and for balancing the centre with the mains.

 

Neither the center or the rears call too much attention to themselves. If the rears were too loud relative to the mains, the rears appeared to dominate the sound field. If too low, the rears were barely audible and not contributing enough to that natural sound propagation. Similar comments apply to blending the center channel.

 

For me this track then, is an example of how it should be done. There are many others on that Jazz list, probably from the same period that I could say the same thing about though.

 

Like Someone in Love from Diana Krall’s Turn up the Quiet:

 

Unfortunately for me, this is an example of how not to do it. There is a guitar that appears to emanate solely from the rear left speaker. Why? Is the idea to put me in the middle of the band? If so it doesn’t feel that way, as the rest of the instruments and Diana’s voice all appeared where you’d expect them to be. Perhaps it’s a limitation of my system; but I just don’t get it.

 

I am happy with most of the examples on Apple’s Classical Spatial list, except for one.

 

Hymne à l'amour (Orch. Ducros), from Gautier Capuçon’s album Emotions.

 

There were loud cracking sounds from my rear speakers causing me to fear for them. So I turned the volume way down to barely audible; but I could still detect these “cracking sounds”. It could be something wrong with my set up, coupled with this having some quite dynamic content. I’ve played plenty of other Spatial streams of all genres of music, including classical orchestras at realistic levels though, without encountering this problem. So I suspect there’s something wrong with this recording/stream. A pity as otherwise it appears to have been done quite well, and I like the music.

 

For Apple Music’s Spatial audio, I have used the Dobly Atmos Surround  5.1.2 output in Audio Midi set-up, to the Black Hole 16 channel virtual audio device. This is then fed into HQPlayer’s input and sent out to the Exasound as an 8 channels device in HQPlayer.

 

I have nothing to say about height channels, as my system is 5.1 only. The last two channels (7,8) are designated as “Left Top Middle” and “Right Top middle”.

 

I imagine when the height channels are present in a system, they would further add to that natural sound propagation, as it occurs in all directions and it might further add to the dynamic three dimensional sound I’ve tried to described. Since HQPlayer has its very useful Matrix Pipeline feature though, I thought I’d make use of it to blend channels 7 and 8 into the centre channel (channel 3). Since this is blending two channels into one channel (which is also receiving its own output) I reduced the blend of each channel 7 and 8 to -24db. I have absolutely no idea if I’m gaining anything from this. Since my Center channel is up on high though, I thought, what the heck, why not? At some stage I might mute the center channels actual output, and just listen for anything I might be getting from channels 7 and 8.

 

Finally, after making the search again for “Spatial” in the Music app I scrolled down beyond Apple’s own curated lists and found the list “Gramophon’s Choice” .

 

These are some truly classic performances, many taken from Deutch Gramophon and, so far, they all sound done right to me. After my all so subtle approach, though, I found I can listen to these with the rear channel volumes higher in relation to the mains than previously, and very much enjoying the result. The rears are more prominent; but in terms of room filling sound, as you would experience in a hall they are sounding quite natural to me. Highly recommended!

 

 

 

 

[The Computer Audiophile]

6 hours ago, Geoffrey Armstrong said:

I have been spending the last week listening to Immersive/Multi-Channel sources through my traditional 5.1 MCH system and here are my impressions so far.

 

First off the MCH part of the system is a kind of “icing on the cake” add on to my two channel system. I put it together with both music and Home Theatre in mind; but have only listened occasionally to multi-channel music and movies through it.

 

It is by no means a dedicated purpose built Immersive system, such as Chris’s. Mine is a hybrid, consisting of a pair of Avantgarde Trio horns with a pair of the same company’s Short Basshorns. The Multi-channel part consists of one Magnepan center channel and two Magnepan rear channel speakers. The latter rest flat against the wall when not in use, and are swung out to be perpendicular to the wall for listening. So the Multi-Channel part is quite tidy and discrete.

 

I figured that, at least the Magnepan have a speed and transparency which can approach the Trios in that regard, even though they can’t match the Trios on dynamics (perhaps less important, at least for the rears).

 

IMO it actually does work quite well as a way of augmenting the main Trio system.

 

The Magnepan centre channel speaker is placed much higher than normal for a centre speaker. The reason for that is, I use a front projection system with a JVC projector beaming to a Stuart Filmscreen electric tensioned screen. Immediately behind the screen are full length windows and behind those on the outside are electric shutters. So the room can be completely darkened for watching movies. I couldn’t place the center channel either below or behind the screen so it sits way up, above the screen in an especially constructed false wall, with a cut out for the speaker. The speaker is angled down slightly towards the listening position.

 

In this room with 3 meter high ceilings, the sound from the Trio system alone has exaggerated height. I know it’s not exactly correct; but I enjoy it. Think of it as a kind of guilty indulgence. I figure, if I were to sit fairly close to a stage, which I like to do, the artists would be performing on a stage raised above me. So in that sense it does kind of correlate to real life.

 

The exaggerated height presentation of the Trio system alone in this room, often places the main voices and instruments in a position, which coincides quite closely, with the mute centre channel speaker. So to have those voices emanating from that position when the centre channel is playing, doesn’t seem out of place to me.

 

What is crucial though is the correct channel blending for MCH sources. By that I mean, the relative gain of the centre speaker compared to the main LF, RF speakers. If the center speaker is too strong compared to the main speakers, those voices will sound disembodied and coming from the rafters. Either lowering the gain on the center speaker or raising the volume on the main speakers, usually allows me to achieve a balance between the center and mains that satisfies me.

 

The same can be said of the main speakers in relation to the two rear speakers. Here also, the blend of the two rears with the two front mains is crucial to my enjoyment of Immersive/MCH sources. With the right blend on the right sources, the results can be very convincing indeed. I believe, more convincing than can be achieved with a two channel system alone. Still I have my reservations. At least on this compromised MCH system.

 

Anyway, Chris’s articles on the subject have inspired me to dust off my old MCH components and give this system more of a serious listen.The addition of Apple’s Spatial/Atmos streams have provided further incentive.

 

To complete the system description, for the MCH system all channels are fed by an old Exasound E28, which has 8 channel outputs. The two main channels are driven by Class D NCore mono-blocks, the center channel by a Class D Mono amp from Nuforce, providing 160w, and the two rear channels are driven by an integrated amp from Crayon audio, providing 190wpc.

 

So I can vary the volume of the rear speakers with the integrated amp’s volume, as well as apply channel gain adjustments in software.

 

The center channel can only be controlled with the Exasound’s volume slider and other software gain settings (in my case using HQPlayer).

 

I’ve played with this system on and off over the years, and already discovered the settings that work best for me when it comes to channel blending for rippped MCH SACDs and DVD-As. There is, of course, quite a lot of variation from recording to recording. As there is with two channels sources. Though, obviously the situation becomes far more complicated with Immersive/MCH.

 

When it comes to the sound, what I find myself enjoying the most is a more subtle multi-channel mix. By that what I mean is a mix which doesn’t place particular intruments/voices exclusively in the rear channels.

 

We all know the rear’s can be used effectively for audience sounds in a live concert and to capture the natural reverberance of instruments being played on the main stage, as the sounds bounce off the halls rear and side walls.

 

What I enjoy most, I believe, is not exactly or not just, this reverb or echo off the walls; but rather when the sound of an instrument appears to be shared between the mains (or one of the mains) and the corresponding rear speaker(s), in a way that causes the sound of that instrument to reach our further into the room and closer to me. This will vary naturally, depending obviously, on how loud the instrument is being played at any given time, and by movements of the musicians and their instruments.

 

By “channel blending”, I can hit on what, for me, is the most convincing presentation. Too strong from the rear and I might just increase the volume from the mains a little (the easiest for me to do), or the opposite when the rears seem barely audible.

 

If the mixing engineer has exclusively placed an instrument in one of the rear channels though, nothing can be done! This just never sounds natural to me. It’s always an effect; an effect that can be fun, depending on the music; but I’d rather it was used sparingly, if at all.

 

Perhaps the problem is one of perception. If someone has splashed out on an Immersive/MCH system, they want to hear those rears, otherwise what’s the point. I don’t want to hear them as separate sources though.

 

Just as us two channel guys want our speakers to “disappear” as the sources of the sound, so it should be for the rear channels IMO.

 

The situation with the center channel is similar; but a little different, in my view. Here it makes perfect sense for a main instrument/voice to be prominently placed in the center channel. Again, though this has to “blend” nicely with the mains, so that some of that voice/instrument is also being reproduced by the mains. I would say that the center channel are to the mains, what the mains should be to the rear speakers. Although of course, the center channel may also have this relationship with the rears. It’s all about natural sound propagation into the room. So, again, the instruments should (at times anyway) appear to reach out towards you/jump out at you, as they do in a live venue.

 

A really great two channel system might be able to achieve the same thing. From listening over the last week though, I’m coming around to the view, that a two channel system would struggle to achieve this as well as a decent MCH system (even one as compromised as mine). Reviews are full of descriptions of two channel gear that can convey the three dimensionality of instruments. With an Immersive/MCH system, depending on the mix, this effect of instruments reaching towards you, must have a dimensional aspect. They gain in dimensions, I’m sure, at the same time as they reach out into the room. Again though, as I’ve tried to describe, this is all varying with time and the actions of the musicians. Too often, descriptions in reviews discussing the “dimensional” aspect, give the impression of an object fixed in space with fixed dimensions. Not something which is constantly varying with time; etc. Perhaps this apparent fixedness of the dimensions comes from the limitations of two channel systems?

 

Whether an Immersive/MCH system is correctly propogating the intruments into your room, will be very much dependant on the decisions of the mixing engineer.

 

I’m certainly no musical snob; but I would say, in general, the more serious the music is considered to be, the more the engineers appear to take the approach of natural sound propogation. The less serious the music may be considered, the more liberties the engineers might be tempted to make with creative use of the channels.

 

Most of the ripped SACDs I have are of classical and jazz, and with most of these a pretty impressive job has been done in the mixing stage in these respects.

 

Over the last week though, I’ve been mainly listening to Apple’s Atmos Spatial streams. So I will take some examples from those.

 

Apple has “Spatial” playlists, each one given a distinct colour for a particular genre of music.

 

As I’m a big jazz fan, I’ll start with an example from the Jazz Spatial list:

 

Tanya from Dexter Gordon’s One Flight Up, sounds to me like a great example of how it should be done. At times the horns reach out towards me in the way I’ve described, and occasionally a thwack on the drum or a rimshot can bounce off the back wall. It’s a good one for me in getting the balance between the rears and mains right, and for balancing the centre with the mains.

 

Neither the center or the rears call too much attention to themselves. If the rears were too loud relative to the mains, the rears appeared to dominate the sound field. If too low, the rears were barely audible and not contributing enough to that natural sound propagation. Similar comments apply to blending the center channel.

 

For me this track then, is an example of how it should be done. There are many others on that Jazz list, probably from the same period that I could say the same thing about though.

 

Like Someone in Love from Diana Krall’s Turn up the Quiet:

 

Unfortunately for me, this is an example of how not to do it. There is a guitar that appears to emanate solely from the rear left speaker. Why? Is the idea to put me in the middle of the band? If so it doesn’t feel that way, as the rest of the instruments and Diana’s voice all appeared where you’d expect them to be. Perhaps it’s a limitation of my system; but I just don’t get it.

 

I am happy with most of the examples on Apple’s Classical Spatial list, except for one.

 

Hymne à l'amour (Orch. Ducros), from Gautier Capuçon’s album Emotions.

 

There were loud cracking sounds from my rear speakers causing me to fear for them. So I turned the volume way down to barely audible; but I could still detect these “cracking sounds”. It could be something wrong with my set up, coupled with this having some quite dynamic content. I’ve played plenty of other Spatial streams of all genres of music, including classical orchestras at realistic levels though, without encountering this problem. So I suspect there’s something wrong with this recording/stream. A pity as otherwise it appears to have been done quite well, and I like the music.

 

For Apple Music’s Spatial audio, I have used the Dobly Atmos Surround  5.1.2 output in Audio Midi set-up, to the Black Hole 16 channel virtual audio device. This is then fed into HQPlayer’s input and sent out to the Exasound as an 8 channels device in HQPlayer.

 

I have nothing to say about height channels, as my system is 5.1 only. The last two channels (7,8) are designated as “Left Top Middle” and “Right Top middle”.

 

I imagine when the height channels are present in a system, they would further add to that natural sound propagation, as it occurs in all directions and it might further add to the dynamic three dimensional sound I’ve tried to described. Since HQPlayer has its very useful Matrix Pipeline feature though, I thought I’d make use of it to blend channels 7 and 8 into the centre channel (channel 3). Since this is blending two channels into one channel (which is also receiving its own output) I reduced the blend of each channel 7 and 8 to -24db. I have absolutely no idea if I’m gaining anything from this. Since my Center channel is up on high though, I thought, what the heck, why not? At some stage I might mute the center channels actual output, and just listen for anything I might be getting from channels 7 and 8.

 

Finally, after making the search again for “Spatial” in the Music app I scrolled down beyond Apple’s own curated lists and found the list “Gramophon’s Choice” .

 

These are some truly classic performances, many taken from Deutch Gramophon and, so far, they all sound done right to me. After my all so subtle approach, though, I found I can listen to these with the rear channel volumes higher in relation to the mains than previously, and very much enjoying the result. The rears are more prominent; but in terms of room filling sound, as you would experience in a hall they are sounding quite natural to me. Highly recommended!

 

 

 

 

Hi @Geoffrey Armstrong thanks for the detailed post. Deutsche Grammophon has some amazing Atmos releases for sure! I'd say it's the leading label for this stuff. I just wish it would release more on Blu-ray Disc for the lossless TrueHD Atmos.

 

I'm going to publish an article tomorrow in which you can see how I'm using convolution filters from Mitch Barnett to correct timing issues with speakers being different distances from the listening position and others room correction items. It's pretty remarkable. 

[Account Closed]

4 hours ago, The Computer Audiophile said:

Hi @Geoffrey Armstrong thanks for the detailed post. Deutsche Grammophon has some amazing Atmos releases for sure! I'd say it's the leading label for this stuff. I just wish it would release more on Blu-ray Disc for the lossless TrueHD Atmos.

 

I'm going to publish an article tomorrow in which you can see how I'm using convolution filters from Mitch Barnett to correct timing issues with speakers being different distances from the listening position and others room correction items. It's pretty remarkable. 

Time and distance correction will work well for your room as it is a single seat listening position. In a larger room with multiple listening positions it is less effective away from the optimized position. Same problem we have faced forever with stereo.

[The Computer Audiophile]

1 minute ago, bobflood said:

Time and distance correction will work well for your room as it is a single seat listening position. In a larger room with multiple listening positions it is less effective away from the optimized position. Same problem we have faced forever with stereo.

Time correction is one small part of multichannel convolution. 

[Geoffrey Armstrong]

9 hours ago, The Computer Audiophile said:

Hi @Geoffrey Armstrong thanks for the detailed post. Deutsche Grammophon has some amazing Atmos releases for sure! I'd say it's the leading label for this stuff. I just wish it would release more on Blu-ray Disc for the lossless TrueHD Atmos.

 

I'm going to publish an article tomorrow in which you can see how I'm using convolution filters from Mitch Barnett to correct timing issues with speakers being different distances from the listening position and others room correction items. It's pretty remarkable. 

I'll read that with great interest Chris. In the past I've applied DRC to the main two channels; but wasn't fully convinced of the results. At the moment I just have correction applied to the Short Basshorns, after measuring the room with Avantgarde's own measuring tools and submitting the recorded files for them to create the optimised curves for my room.

[wisechoice]

21 hours ago, Geoffrey Armstrong said:

For Apple Music’s Spatial audio, I have used the Dobly Atmos Surround  5.1.2 output in Audio Midi set-up, to the Black Hole 16 channel virtual audio device. This is then fed into HQPlayer’s input and sent out to the Exasound as an 8 channels device in HQPlayer.

 

I have nothing to say about height channels, as my system is 5.1 only. The last two channels (7,8) are designated as “Left Top Middle” and “Right Top middle”

Thanks for the very richly detailed account of your experience with surround sound! It sounds like it has also been richly rewarding for you (as it has for me, too).

 

That said, please permit me to point out that you've made an error in your macOS speaker configuration. If you only have a 5.1 setup, with no height speakers, the correct setting in Audio Midi Setup is 5.1, not 5.1.2. Then your system will render Atmos correctly to the 5.1 configuration if that's what you're listening with. If you set it to 5.1.2, there is no guarantee that it will be rendered correctly. In fact, because Atmos is object-based rather than channel-based, there's a good chance that any musical or sound elements above the listening position (let's say a balcony choir in a classical piece, for example) will be improperly rendered, without the detail they should have. The difference may be subtle for some music, but more dramatic for other music. That's because the rendering in an object-based system like Atmos isn't merely additive. The format is supposed to be totally independent of the number of speakers you're listening with. So you should even be able to listen to an Atmos mix rendered in mono or stereo (not binaural) and still hear all the elements *somewhere*, even those that were mixed to rear or height channels. Note that this is not a "mixdown," either, because there were never discrete channels in the original Atmos mix, only objects.

Also, for others who are wondering about whether it's worth taking the kind of dive that Geoffrey (or Christopher, or myself) have made into any kind of surround or immersive format, here's my very simple, straightforward and affordable suggestion: find a way to get four speakers, any* four speakers, connected to a Mac via whatever DACs or built-in outputs you have available, then create an aggregate device in Audio MIDI Setup and configure it as quadrophonic. Don't get bent out of shape about speaker positioning, just make sure they're all equal distances from the listening position (this way you won't need to worry about channel delay/time alignment), and on the same vertical plane as your ears. Use AMS to calibrate the levels of your speakers using pink noise. Set the volume in ASM's preferences to something that won't break your system, or your ears, and then use any SPL meter you like (including a free one from the iOS or another app Store). It doesn't matter what level the speakers are calibrated to, just as long as they all match. In fact, if you don't have or don't want to go to the trouble of using an SPL meter to begin with, just balance them by ear, as Geoffrey has been doing while listening to music. But do spend at least a moment balancing levels with pink noise. It's worth it.

Then you can listen to or watch a range of Atmos (or 5.1) content via the Music app, TV app, or the Berliner Philharmoniker, and get a sense for what is possible with surround sound. In my opinion, a quadrophonic setup will get you at least 50% of the experience that is possible with a setup that has been thought through more carefully. You won't miss the center speaker if you're equidistant from all four speakers.

* From what I understand, research shows that people are most sensitive to differences between speakers when auditioning a single speaker. In stereo or multichannel, you will be less sensitive. Ideally, all your speakers should be the same in an Atmos setup, and they should all be full-range. But it doesn't need to be perfect to begin with, you can build from here.

[Geoffrey Armstrong]

2 hours ago, wisechoice said:

That said, please permit me to point out that you've made an error in your macOS speaker configuration. If you only have a 5.1 setup, with no height speakers, the correct setting in Audio Midi Setup is 5.1, not 5.1.2. Then your system will render Atmos correctly to the 5.1 configuration if that's what you're listening with. If you set it to 5.1.2, there is no guarantee that it will be rendered correctly. In fact, because Atmos is object-based rather than channel-based, there's a good chance that any musical or sound elements above the listening position (let's say a balcony choir in a classical piece, for example) will be improperly rendered, without the detail they should have. The difference may be subtle for some music, but more dramatic for other music. That's because the rendering in an object-based system like Atmos isn't merely additive. The format is supposed to be totally independent of the number of speakers you're listening with. So you should even be able to listen to an Atmos mix rendered in mono or stereo (not binaural) and still hear all the elements *somewhere*, even those that were mixed to rear or height channels. Note that this is not a "mixdown," either, because there were never discrete channels in the original Atmos mix, only objects.

Thank you for your clear explanation and for correcting my error. In fact 5.1 is the first option I chose in Audio Midi set-up, since as you point out, that corresponds with the number of speakers I actually have.

 

With my first attempt though, I couldn't get this to work through BlackHole 16Channel version as input to HQPlayer for playing out to my Exasound 8 channel DAC. When I changed to 5.1.2 Atmos, I got it working. So I figured I may as well blend the height channels into the Center Channel with HQPlayer's Matrix Pipeline tools.

 

Having said that, I have now reverted to 5.1 in Audio-Midi set-up and set HQPlayer as outputting to 6 channels and it's all working fine. I must have made some other mistake in my first attempt.

 

[The Computer Audiophile]

My review of the system is up!

 

 

[firedog]

NativeDSD is now offering 5.1.4 audio 

 

 

https://www.nativedsd.com/product-tag/auro3d/?goal=0_718318139b-65a4d1a89b-163035634&mc_cid=65a4d1a89b&mc_eid=90c7448ee6

[The Computer Audiophile]

38 minutes ago, firedog said:

NativeDSD is now offering 5.1.4 audio 

 

 

https://www.nativedsd.com/product-tag/auro3d/?goal=0_718318139b-65a4d1a89b-163035634&mc_cid=65a4d1a89b&mc_eid=90c7448ee6

 

It's a great step. Can't wait till the site offers Atmos.