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DIY Surround Pre-Pro: Apple Logic Pro + Dolby Atmos

DownUnderGazza

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TL, DR;
  1. What if we could configure Apple’s Logic Pro to be your Surround Preamp-Processor (including up/down mixing);
  2. Control input selection and output levels via Focusrite’s Rednet R1 controller; and
  3. Send the input/output channels wherever you need via Dante?
PREAMBLE
We all are very aware how poorly AV Surround Preamps / Amplifiers perform under test. What if there was a way to bypass all that poor performance using professional gear?

This is a highly DIY approach, and as I haven’t actually tried it myself, it may not work. Please do NOT buy gear based on my thoughts to try this as you may NOT get the results you hope for. Also, I’ve NOT addressed getting video, Dolby Vision or similar, out of the system. I'm assuming something like a Mac Mini's HDMI output would suffice.

Minimum System Requirements:
— An Apple Mac
— Apple’s Logic Pro software
— Sufficient Input/Output channels to experiment with.

High-end dream system? Read on…


INSPIRATION
The inspiration for this idea was triggered by:
  1. Apple’s Logic Pro mixing / mastering software NOW supports Dolby Atmos, including Up / Down surround mixing! This is NEW.
    1. https://www.apple.com/logic-pro/
  2. Focusrite’s Rednet R1got me drooling! PoE over a single ethernet cable, a contender for the centre piece of a top notch system.
    1. https://pro.focusrite.com/category/audiooverip/item/rednet-r1

rednetr1-front-rear-1090-869.png



  1. Focusrite’s Rednet components are top line pro studio gear and in theory offer exceptional performance. Of course subject to actually being tested by ASR! (https://pro.focusrite.com/category/audiooverip)
  2. Dante (https://www.audinate.com/)
    1. Yep, the defacto Audio over IP / Ethernet standard. A surprisingly simple way to route audio (and now video) between components and apps.

LOGIC PRO at the Heart of the system
Ok, the basics of the idea is to set up Logic Pro with as many input and output channels as needed and let it control everything.

So for example, for stereo inputs, allocate two channels for Safari sources (think Netflix, YouTube etc), two channels for iTunes / Apple Music, two channels for any other sources, such as sound in from your Smart TV (though not sure how best to capture a TV’s audio out, eARC or Toslink?). Of course if any of these sources support Dolby Atmos, then feel free to allocate up to 16 input channels each. Go ahead, Logic doesn’t mind.

Any stereo input can in theory be upmixed using the Logic Atmos plug-in. All inputs, whether stereo upmixed or full Atmos, would be sent to the main 16-channel output ‘Bus’ for final volume control. (https://support.apple.com/en-au/guide/logicpro/lgcp8e75f0b5/mac)

Then set up however many output channels make sense in your situation. Here I’m relying on the notion that we will be able to use Logic to ‘Downmix’ the Dolby Atmos channels to our actual surround channel reality.

Remember, this is professional level software so each channel can have as detailed EQ and delay time controls as required. Need High-pass or Low-pass filters, easy! Need Four x 16 = 64 input channels, piece of cake! The level of control possible is huge. But so is the resulting complexity that goes with it.

To aid in all this channel mapping, something like Dante’s Via software for multi-channel routing into and out of Logic Pro might help (https://www.audinate.com/products/software/dante-via)

Then it’s a case of hooking up one’s input/output Audio interfaces to connect Logic Pro to the real world.

MacOS has the ability to create a ‘Virtual Audio Interface’, so we could cascade as many USB interfaces as we have to hand. I have MiniDSP, SMSL and Matrix-Digi stereo DACs, so could I create a 5.1 output mix with what I already have. I also have Logic Pro with all the Atmos plugins, but haven't yet attempted to try out this idea.


A HIGH-END EXAMPLE
As an example of starting from scratch with professional gear, I’ve used Sweetwaters as a trusted source, but you could find the same on Amazon if preferred. Assuming buying from scratch, going for a full 16 balanced channel output Atmos configuration and at the upper end of the price spectrum:

Apple Mac MiniUS$699https://www.apple.com/shop/buy-mac/mac-mini
Apple Logic ProUS$199https://apps.apple.com/us/app/logic-pro-x/id634148309?mt=12
Audinate Dante ViaUS$60https://www.audinate.com/products/software/dante-via
Focusrite’s Rednet R1 ControllerUS$1,000https://www.sweetwater.com/store/de...-desktop-remote-controller-for-red-interfaces
Focusrite RedNet A16R MkII 16x16 Dante Audio InterfaceUS$3,600https://www.sweetwater.com/store/de...-rednet-a16r-mkii-16x16-dante-audio-interface
Up to Four DB25 to XLR (male or female) or TRS breakout snakes for the RedNet A16Rfrom 4x US$78https://www.sweetwater.com/store/search.php?s=DB-25+snake
Up to Four XLR /TRS Patch-bays to ‘expose’ the balanced connectors for easy front accessfrom 4x US$100https://www.sweetwater.com/store/search.php?s=xlr+patchbay
A nice Rack mount case (6U minimum) to house all the Pro gearfrom US$45https://www.sweetwater.com/c685--Studio_Equipment_Racks
EXAMPLE TOTALUS$6,315

Misc pro XLR / TRS balanced cables to hook up powered speakers or balanced amps, and ethernet cables to hook up the Dante components would be needed.


MAKING IT WORK
Shopping is the easy part. As is using what one has to hand, though not as much fun.

The hard part is figuring out how to make all this work seamlessly, and I admit while this SHOULD work in theory, there’s no guarantee it will in practise.

Setting up Logic Pro as the heart of one’s AV system is not for the faint of heart. Having the Rednet R1 in theory makes input selection and overall volume control easy, I have no idea how challenging it would be in practise. For example, could it also trigger switching of video sources?

In short, I don’t know how to go about doing this, but thought sharing the idea might inspire someone with Logic to have a go and report back.

Anyway, idea shared.
 

iMickey503

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What gear do the Movie houses use? I would just duplicate that.

That way your investment pays for itself. You offset the costs by having the theater open to the public on movie events, and you can legitimately charge $20 bucks a ticket to see the movie per person, and sell refreshments to recoup all the cost of your setup and for further upkeep and maintenance.

People run Bed & Breakfasts. This would be like the same thing. But you get to take the price of your gear as a Tax write off.

Come to think about it? This would be a great way to expense your expensive Audiophile setup.

Its kind of like having your Gear you buy Pay you for buying it. And when your done paying it all off? You can just close the Room in your home, and enjoy you outsmarted the system.
 
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DownUnderGazza

DownUnderGazza

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From vague recollection, some of the gear used by Movie houses has been tested here on ASR, and found to not be that great. While designed as a turn key solution, it’s certainly not cheap.

My suggestions above provide access to the same tools as used by those mixing Dolby Atmos soundtracks, and the complete freedom to mix and match input and output quality vs price points to suit.

The Rednet based solution is way cheaper than some of the AV Pre-Pro options on the market.

Absolutely agree on potentially having a small side business if one wanted the hassle.
 

Blumlein 88

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I don't know how such a setup would work out. I like your thinking here, and hope something like this is possible now or in the near future. Dolby doesn't want it, but obviously the smartest way is for all that Dolby processing to be in software that can be updated as changes occur. The current paradigm where all this get changed in hardware that becomes obsolete every 2 to 3 years is retarded. I don't like subscription software, but this is a place where maybe subscription decoding software would make sense.
 
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DownUnderGazza

DownUnderGazza

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The thing about Apple software is that it isn’t subscription based.
Even though I haven’t sat down to figure out how to use it yet, I’ve owned Logic Pro for several years. All this Dolby Atmos processing, plug-ins, up/down mixing just arrived. No extra cost, just a download ready when I was.
It was the ‘free’ arrival of Dolby Atmos processing together with spotting the drool worthy Rednet R1 controller that got me thinking.
 

Vincentponcet

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I don't understand how you can feed apple logic pro from a streaming app ( Netflix, Disney plus) or a ripped file like an mkv.
 

Sancus

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Logic Pro is a production tool, not a consumer playback tool. It's very unlikely that it plays back consumer content sources at all. None of the other production tools, including Dolby's own, play consumer content. The data formats during production of Atmos are different from final rendered production output.

Now, Macs can decode Atmos themselves as of recently. But only from official Apple content streaming sources(Apple TV & Music), not from physical media or any other software. Apparently Apple is using their own spatial audio decoder for this, not the Dolby one, which is why it's possible.

To my knowledge Dolby has never made consumer-content playback software available for any general purpose computer, at any price.
 

chris719

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It's crazy how people and the market just accept Dolby stuff. There's no reason for our sound to be locked down like this, a royalty free format/codec could easily be designed given how easy it is to do multichannel audio.
 

Vincentponcet

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It's crazy how people and the market just accept Dolby stuff. There's no reason for our sound to be locked down like this, a royalty free format/codec could easily be designed given how easy it is to do multichannel audio.
Design your own, and build all the mixing equipments.
Flac is multi-channels capable, but does not support objects.
 

chris719

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Design your own, and build all the mixing equipments.
Flac is multi-channels capable, but does not support objects.
Fair enough. I still think it could/should be done.

The reality is we don’t need object based sound. Most people don’t even have setups that take full advantage of AC-3 from 25 years ago or whatever it is. They’re using soundbars. We’ve gone backwards, I would be happy with a modernized but open standard.
 

polmuaddib

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I don’t really get the point. Do you want to use this setup to listen to Atmos content or produce it?
If it is just to listen, then why do you assume that existing AVR/AVPs are inferior? They may measure poorly compared to stereo DACs but they are audibly transparent. Most of them, at least.
 

FrantzM

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Hoping this is not construed as crapping on a thread:

There are a few things to keep in perspective in this hobby of ours. AVRs and Pre/Pro have measured "poorly" here at ASR. Some are not worth the prices asked for. It remains however that several AVRs that were reviewed here, from Denon in particular also a few others, have done more than only clearing the threshold of audible transparency: those recommended AVRs and pre/pro (?), have provided a good level of performance (SINAD >80 dB, extended, FR, etc) and features: Things like , easy turn on and off :), Atmos and all commercial advanced codecs, Spotify Connect, Auro-3D and Atmos upmixing, a remote, A physical volume control, source switching, a tuner, sometimes a Phono preamp and in the case of AVRs, back-up amplifiers ;)... plus a modicum of support from the manufacturer in a one-box solution... all that for less than the cost of components of this project.
On top of that this project will require a good software or app to make it usable by anyone but its designer, and likely will require a component or two to plug it to other devices. I fear that by the time it is done and ready, it will be close in pure components costs, to $10,000.oo ... by then you are lurking in the territory of a Storm Audio or Trinnov or JBL SDP, second hand ... even new ... If you are willing to go that far financially, the jump to Trinnov- and its real competitors make sense... makes more sense...
Now if that is the basis of a future commercial product/project, to challenge the aforementioned Trinnov or Storm, etc. then it is a definitely worthy endeavor. It won't be a walk in the park but the current SOTA in Pre/Pro would have been challenged. The only way to advance any industry.

Peace.
 

Sancus

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It's crazy how people and the market just accept Dolby stuff. There's no reason for our sound to be locked down like this, a royalty free format/codec could easily be designed given how easy it is to do multichannel audio.
That already exists. It's called DTS:X. So far it's mostly lost to Dolby. I work on open source, unfortunately among enthusiasts there is this idea that a technology is better just because it's open. The reality is not so simple. There are pros and cons.
 

wjp007

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I tried a similar exercise with a Windows device using Voicemeeter which is a mixing app but also let's you have multiple audio output devices. You can route the different channel pairs to different DACs. But it just didn't sound right. I think it was a result of delays in the different paths. I didn't have access to multiple DACs of the same model. I think with some experimenting it should have worked, but I just gave up and reverted to my AVR for multichannel music. I have speaker switch and go between the AVR for multichannel and a DAC/AMP for stereo.
 

Vincentponcet

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I tried a similar exercise with a Windows device using Voicemeeter which is a mixing app but also let's you have multiple audio output devices. You can route the different channel pairs to different DACs. But it just didn't sound right. I think it was a result of delays in the different paths. I didn't have access to multiple DACs of the same model. I think with some experimenting it should have worked, but I just gave up and reverted to my AVR for multichannel music. I have speaker switch and go between the AVR for multichannel and a DAC/AMP for stereo.
You should use one multi-channels DAC like the ones used in the pro audio space.
 

wjp007

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You should use one multi-channels DAC like the ones used in the pro audio space.
Yeah nah, I'm was trying to get this to work without spending another $1500 on a multichannel DAC. But that seems like they only real way to get this to work.
 

chris719

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That already exists. It's called DTS:X. So far it's mostly lost to Dolby. I work on open source, unfortunately among enthusiasts there is this idea that a technology is better just because it's open. The reality is not so simple. There are pros and cons.
The difference is with encumbered, closed standards you can’t even buy ICs or implement the codec without being a licensee. It has nothing to do with any technical opinion I have about Atmos.
It creates a barrier to entry for small companies looking to compete. Look at what HDMI+HDCP has done to video hardware. It’s almost exclusively the domain of big players.

The OP probably wouldn’t be asking this question if there were halfway decent AV processor options that aren’t 5 figures.
 
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Sancus

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The OP probably wouldn’t be asking this question if there were halfway decent AV processor options that aren’t 5 figures.

All the Denon AVRs with pre-outs work completely fine as processors, any belief to the contrary is just confusion. And they don't cost anywhere near 5 figures. In fact, the amount of hardware and software you get in an AVR is really really tough to compete with. Some of them are not even making money, they're just prestige businesses attached to Japanese brands that don't care about margins.

The difference is with encumbered, closed standards you can’t even buy ICs or implement the codec without being a licensee.
Yeah, my point was exactly that. The encumbering you're speaking of also comes with market advantages. The open approach also has advantages, but it's not a clear cut one is better than the other. Sometimes, the proprietary approach directly produces better technology because it's better funded and the company in question can enforce quality standards among partners. When you can tightly integrate hardware+software and prevent anyone from releasing products that don't meet your standards, you can often make a better product, just ask Apple.

Regardless of the reasons, despite the availability of royalty free/open options, Atmos still became the standard for film/tv audio.
 

chris719

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All the Denon AVRs with pre-outs work completely fine as processors, any belief to the contrary is just confusion. And they don't cost anywhere near 5 figures. In fact, the amount of hardware and software you get in an AVR is really really tough to compete with. Some of them are not even making money, they're just prestige businesses attached to Japanese brands that don't care about margins.


Yeah, my point was exactly that. The encumbering you're speaking of also comes with market advantages. The open approach also has advantages, but it's not a clear cut one is better than the other. Sometimes, the proprietary approach directly produces better technology because it's better funded and the company in question can enforce quality standards among partners. When you can tightly integrate hardware+software and prevent anyone from releasing products that don't meet your standards, you can often make a better product, just ask Apple.

Regardless of the reasons, despite the availability of royalty free/open options, Atmos still became the standard for film/tv audio.
The Denons are okay processors with various limitations and have unbalanced outputs.

Dolby’s ability to strong-arm longtime partners into adopting their solution doesn’t mean it’s the best thing for consumers. The same thing can be seen with Dolby Vision.
 

Sancus

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The Denons are mediocre processors with various limitations and have unbalanced outputs.
Mediocre compared to what actual product that is on the market?

Go find me a 13-channel DAC that includes channel delay and level set, decent room correction and bass management for less than the price of an X3700H($1600 currently, apparently) and has >97dB SINAD. Completely ignoring codecs, video inputs, etc.

The only things I know that even come close to that price per channel and performance are pro audio interfaces, and they usually can't do room correction or bass management internally.

Balanced outputs are nice-to-have but don't actually do anything unless you have serious ground loop problems or the like.
 
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