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Stereo to Dolby Atmos 7.1.4

Richx200

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May 20, 2024
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Hello,

For the past couple of months, I have been exploring converting stereo recordings to Multichannel, 3D, Surround, Atmos, and DTS. In most of the formats, I have a pretty good idea what is going on during the conversion, but Atmos has me scratching my head.

A plugin by Penteo Pro+ ($800.00) claims to be able to convert stereo into many different formats, including Dolby Atmos, which is where I get lost. My understanding of Atmos is that it isn't a format but According to AI:

"Dolby Atmos is an immersive, object-based audio technology that expands traditional surround sound by adding overhead sound elements, creating a three-dimensional soundscape that makes you feel as if you are inside the action. Instead of assigning sounds to fixed channels, Atmos treats sounds as individual "audio objects" that can be precisely placed and moved anywhere in the 3D space"

So if that is true, the only thing Penteo does is run the stereo through a multichannel algorithm for 3D placement that would be feed into an Atmos player and call it Atmos. So I had to check this out. I bought a Dolby Atmos album YGGDRASIL - 2L170 - 9.1.4. I had a little trouble playing it because the streaming player I have didn't handle the (.MKV) format. So I played it through My Nvidia TV Pro and copied it to Blu-ray Disk and played it through the Blu-ray player; it sounded outstanding.

Got a trial version of Penteo and using a Reaper DAW I converted some HD stereo recordings into what was supposed to be Atmos 7.1.4 First the default format for the recordings was (.WAV) not (.MKV). The recordings sounded nothing like the album I bought, although it did sound good despite no having a lot of 3D placement.

Well now I have to ask is there anything wrong with my findings.

Can a plugin convert stereo into Dolby Atmos?
Is there another format that can produce Atmos for music?
Will this road of conversion lead to a better sound than the Upmix, Dolby Surround on a player?
Just more snake oil?

Thank you for your time.:)
 

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ATMOS is a delivery format. You could encode with ATMOS but that isn’t really what I think you are looking for. It sounds like you want surround processing/upmixing. Lots of options there and the resulting quality varies between them.
 
There is surround upsampling built into Windows 11 with the Dolby Atmos app that comes with Windows. If you have an Atmos-enabled receiver connected to a PC, just enable Atmos in your sound settings and play music back with Media Player and it will upsample to 7.1.4 or whatever your setup is. It works pretty well. You definitely don't need to buy an $800 professional plugin (and your output from Reaper is going to be whatever your Reaper render settings are, FWIW).

[edit] From looking at the Penteo website it looks like this is a tool for professional mixers, to allow them to mix to whatever surround format they have available (for example, 7.1.2) and then Penteo will automatically convert that to a 9.1.2, 9.1.4, 11.1.2, 11.1.4, 5.1, 5.1.2, 7.1, stereo, etc., mixes. It's not really for taking a finished stereo mix and "upconconverting" that to a 7.1.4 atmos mix.
 
ATMOS is a delivery format. You could encode with ATMOS but that isn’t really what I think you are looking for. It sounds like you want surround processing/upmixing. Lots of options there and the resulting quality varies between them.
Sorry, but I'm only looking to see if it is possible to upmix stereo to Atmos not for personal use, maybe for the future.
 
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There is surround upsampling built into Windows 11 with the Dolby Atmos app that comes with Windows. If you have an Atmos-enabled receiver connected to a PC, just enable Atmos in your sound settings and play music back with Media Player and it will upsample to 7.1.4 or whatever your setup is. It works pretty well. You definitely don't need to buy an $800 professional plugin (and your output from Reaper is going to be whatever your Reaper render settings are, FWIW).

[edit] From looking at the Penteo website it looks like this is a tool for professional mixers, to allow them to mix to whatever surround format they have available (for example, 7.1.2) and then Penteo will automatically convert that to a 9.1.2, 9.1.4, 11.1.2, 11.1.4, 5.1, 5.1.2, 7.1, stereo, etc., mixes. It's not really for taking a finished stereo mix and "upconconverting" that to a 7.1.4 atmos mix.
Not connected to the receiver, but it is an intriguing idea. For now, I'm just curious how a plugin could convert stereo to "Atmos" and Penteo was the only plugin I could find that made the claim. So when I tried to convert stereo to "Atmos" using Reaper and Penteo the results (reported by the Anthem 1140 window) were Multi Channel PCM not "Atmos" which prompted the questions above. So far I have only gotten an Atmos output from Anthem when the input was TrueHD, DD+ and .MVK never from a .WAV format.
 
I don't know much about Atmos and I know nothing about the Penteo Pro+ plug-in...

Personally, I mostly use the up-mixing features on my AVR. It's only 5.1 but it has "hall" and "theater" settings for some delayed reverb in the rear (and some other settings that I don't use).

A couple of times I made my own surround remix from a mono concert video. I used some "fake stereo" effects along with some delayed reverb in the rear. When there was talking between songs I panned it to the center. I took appause from different parts of the recording and panned it to the rear at appropraite times. In one of the concerts there was a call-and-response with the audience and I panned the audience response to the rear.

You might think about making a test file or test-disc so you can pan sound to known locations. I did that once with 5.1 with my voice saying, "front left", "center", etc.

The recordings sounded nothing like the album I bought,
Of course not. They have the original multitrack recordings with different instrumets and volcals on separate tracks. Often every drum and cymbal is recorded with a separate microphone to a separate track. They can mix, and pan-position those tracks wherever they want. They cna also adjust the levels of the different tracks, fading them up-and-down independently and they can apply different effects to the different tracks.

Even if you had original multi-track recording(s) you'd probably come-out with a different mix.
 
I use the Penteo Pro+ plugin in conjunction with the HLHost VST running on a small PC on my living room rig. It sounds slightly more authentic than the Meridian 621 it replaced for that 4.0 setup. I'm able to toggle between native 2.0, Atmos 4.0 and XTalk cancellation 2.0 using my phone. They all sound different and my preference is largely dictated by the specific content being played. The Atmos upmix appears to enlarge the listening venue in all dimensions and slightly increases reverb. The XTalk filter appears to increase the depth of the soundstage without otherwise altering the venue.
 
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Sorry, but I'm only looking to see if it is possible to upmix stereo to Atmos, maybe for the future.

I don't know much about Atmos and I know nothing about the Penteo Pro+ plug-in...

Personally, I mostly use the up-mixing features on my AVR. It's only 5.1 but it has "hall" and "theater" settings for some delayed reverb in the rear (and some other settings that I don't use).

A couple of times I made my own surround remix from a mono concert video. I used some "fake stereo" effects along with some delayed reverb in the rear. When there was talking between songs I panned it to the center. I took appause from different parts of the recording and panned it to the rear at appropraite times. In one of the concerts there was a call-and-response with the audience and I panned the audience response to the rear.

You might think about making a test file or test-disc so you can pan sound to known locations. I did that once with 5.1 with my voice saying, "front left", "center", etc.


Of course not. They have the original multitrack recordings with different instrumets and volcals on separate tracks. Often every drum and cymbal is recorded with a separate microphone to a separate track. They can mix, and pan-position those tracks wherever they want. They cna also adjust the levels of the different tracks, fading them up-and-down independently and they can apply different effects to the different tracks.

Even if you had original multi-track recording(s) you'd probably come-out with a different mix.
Thank you for your reply. While I am aware of the many 3Ds, Surround, Multichannel, and spacial Audio VSTs and plugins available both for free and purchase I was just trying to get more information about converting stereo to Atmos: is it possible or just more snake oil?

P.S. A great Spacial Audio VST for Free is OrilRiver,

 
I use the Penteo Pro+ plugin in conjunction with the HLHost VST running on a small PC on my living room rig. It sounds slightly more authentic than the Meridian 621 it replaced for that 4.0 setup. I'm able to toggle between native 2.0, Atmos 4.0 and XTalk cancellation 2.0 using my phone. They all sound different and my preference is largely dictated by the specific content being played. The Atmos upmix appears to enlarge the listening venue in all dimensions and slightly increases reverb. The XTalk filter appears to increase the depth of the soundstage without otherwise altering the venue.
Sweet set-up, and thank you for your reply, you are just the guy I want to talk to:

Can you tell me how you converted stereo to Dolby Atmos ?
How did you confirm your set-up was playing in "Dolby Atmos" ? (all I could get was Multi PCM)
What file format are the recordings?
Aside from the spacial effect, how is the 3D placement ?

Sorry for all the questions, but my understanding of the process is that multichannel recordings are used for the effects and 3D placement. If that is the case, Penteo is filling in the gaps with an algorithm to simulate the Atmos effect. Also, there is the question of file format.

Thank you for your time :)
 
@Richx200:
Can you tell me how you converted stereo to Dolby Atmos ?
Review the VST chain detailed onthis post. Stereo data is streamed via the Minidsp U-DIO8 to the Penteo VST3. This plug-in supports many different up-mixer topologies including Atmos. My 4.0 configuration is very simple, but Penteo supports very large speaker arrays. Volume trims are available for center, Lss-Rss, Lsr-Rsr, LFE and uppers so that you can tweak the amount of ambience to your preferences. In my particular situation, the rears are relatively close to the primary listening position so I added a delay VST to the output from Penteo to increase their virtual distance.
How did you confirm your set-up was playing in "Dolby Atmos" ? (all I could get was Multi PCM)
Penteo+ is an Encoder which converts incoming stereo PCM into multichannel PCM using the Atmos upmixer algorithm, licensed from Dolby. It renders in "Dolby Atmos", but cannot decode an Atmos bitstream.
What file format are the recordings?
My audio library is lossless .flac. However, I can play (stream) audio from Qobuz, Spotify, Youtube in any format.
Aside from the spacial effect, how is the 3D placement ?
My living room rig is only a 4.0 system. The front channel content is not adversely affected by the upmixer and still contains a phantom center, virtual depth and width and other typical stereo spacial cues. The rear channels merely convey the notion of a larger venue, but without precision. This is in stark contrast to playback of movie soundtracks on my home theater, in which Atmos mixes contain very precise positional cues intrinsic to each scene.
 
Please note! Upmixing plugins only deliver PCM streams! Multi-channel yes, but not ATMOS-encoded... Dolby does not allow this encoding by plugins! They must ALL use the Atmos TrueHD/DD+JOC codec (2 versions: Dolby Atmos Production Suite (DAP) and Dolby Atmos Mastering Suite (DAMS).
Remember that TrueHD, which is the only lossless version, is limited to 48 kHz, and that DD+, also restricted to 48 kHz, is lossy!
 
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