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

[kongwee]

LPX totally not for enjoyment app. You can't decode encode on fly, not to mention about the audio interface.

 

[chris719]

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.

Mediocre is perhaps the wrong word, but this is far from an ideal product compared to what should and would be on the market if HDMI, HDCP, and Dolby codecs were open to licensing with reasonable terms for small businesses.

I don't want a huge box with 11+ channels of power amplifiers in it just so I can ignore them. I agree it's not a big issue, but I believe all products should have balanced outputs, because ground loops do still happen, especially as you add more devices to a chain. Not everything is or will be Class II double insulated construction. Referencing your signal to an inter-chassis connection is not ideal. I'd also appreciate some options with fewer channels, more Dirac options, and MiniDSP-like capabilities.

I suspect that many companies have wanted to make devices like this but haven't been able to risk the outlay required. My dealings with the HDMI Forum have been unpleasant enough while working for a large multinational corporation. Good luck buying transceivers that support the latest standards, even if you don't need HDCP.

You're not wrong, but my overall point is that the current state of affairs is not great, and Dolby's business model is indirectly contributing to it. Options for separates and processors have been steadily decreasing. Once soundbars and lock-in eat what's left of the AVR market, what then?

 

[Sancus]

You're not wrong, but my overall point is that the current state of affairs is not great, and Dolby's business model is indirectly contributing to it.

I don't disagree with you at all, my problem is people complain about this kind of stuff but they're generally not willing to put their money where their mouth is.

The stuff Dolby does costs money to do, they've chosen to charge businesses directly as their model. I'm all for open standards, but unfortunately a lot of the time doing that means that the folks who build the specs and the software don't get paid. This is a topic of some discussion in the open source community right now, but it's always been a problem.

All that said, if I was running Dolby, I would probably make their licensing more friendly to smaller businesses. They're no doubt losing some revenue because of how difficult they are to work with. But considering their near-monopoly status in Film/TV and accelerating growth in music, it's hard to argue that they've made the *wrong business choices* in general.

Are those business choices bad for consumers? Certainly, but until we figure out how to do a better job of funding open source there's not a lot of great business model choices for R&D/spec companies like Dolby.

 

[chris719]

I don't disagree with you at all, my problem is people complain about this kind of stuff but they're generally not willing to put their money where their mouth is.

The stuff Dolby does costs money to do, they've chosen to charge businesses directly as their model. I'm all for open standards, but unfortunately a lot of the time doing that means that the folks who build the specs and the software don't get paid. This is a topic of some discussion in the open source community right now, but it's always been a problem.

All that said, if I was running Dolby, I would probably make their licensing more friendly to smaller businesses. They're no doubt losing some revenue because of how difficult they are to work with. But considering their near-monopoly status in Film/TV and accelerating growth in music, it's hard to argue that they've made the *wrong business choices* in general.

Are those business choices bad for consumers? Certainly, but until we figure out how to do a better job of funding open source there's not a lot of great business model choices for R&D/spec companies like Dolby.

You raise some valid points. I don’t even think the standards need to be purely open source development efforts. It can work out pretty well when chip companies or industry working groups develop a spec, because they are using it to drive chip sales and not relying on it as a major source of revenue. USB is a good example of this working. Then again, HDMI didn’t turn out as friendly.

Agree that some tweaks to how they do business would go a long way. If Dolby were more open on decoders, that would probably help consumers. Same thing with licensing terms to encourage startups. I’m afraid that many of Dolby’s key customers like the current state of affairs, though. If you’re a big consumer electronics company, you don’t really want to lower any barriers to entry.

 

[phoenixdogfan]

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.

Have to agree on this one. I would strongly prefer to run all Codecs on a small, Windows or Apple box, pipe lpcm out via usb to a multi channel dac or dacs, control volume via software such as Jriver, have multi-channel dsp, peq, bass management and video rendering with no lip sync issues in a single software player with whatever required plugins for Dirac, etc. And I can do that--up to 7.1 with JRiver, but no further b/c the owners of the object based Codecs (Atmos and DTS-X) and the most advanced channel based codec (Auro 3D) will not allow their proprietary codes to run on a PC.

So, I do have a Smyth A16 Realizer which will already do ATMOS and DTS-X, and soon Auro 3D, and that's my route forward. Only problem is PEQ and DSP by channel are currently non-existent, but may be added in the future via firmware download--if (and it's a mighty big if) Smyth remains solvent and a going concern. If they do remain solvent, I have both a viable home theater processor and the gold standard for binaural audio speaker emulator for headphones already paid for and sitting in my equipment rack. From there it's a relatively trivial matter to buy a couple of Aiyima A07's and four used surround speakers to serve for height channels.

 

[BJL]

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

View attachment 196862

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 Mini	US$699	https://www.apple.com/shop/buy-mac/mac-mini
Apple Logic Pro	US$199	https://apps.apple.com/us/app/logic-pro-x/id634148309?mt=12
Audinate Dante Via	US$60	https://www.audinate.com/products/software/dante-via
Focusrite’s Rednet R1 Controller	US$1,000	https://www.sweetwater.com/store/de...-desktop-remote-controller-for-red-interfaces
Focusrite RedNet A16R MkII 16x16 Dante Audio Interface	US$3,600	https://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 A16R	from 4x US$78	https://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 access	from 4x US$100	https://www.sweetwater.com/store/search.php?s=xlr+patchbay
A nice Rack mount case (6U minimum) to house all the Pro gear	from US$45	https://www.sweetwater.com/c685--Studio_Equipment_Racks
EXAMPLE TOTAL	US$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.

Instead of using the expensive Focurite/Dante interface, couldn't you just use a thunderbolt interface with sufficient analog outputs?

 

[DownUnderGazza]

Instead of using the expensive Focurite/Dante interface, couldn't you just use a thunderbolt interface with sufficient analog outputs?

Absolutely, several interfaces could be combined into a single ‘virtual interface’.

The cost of Focusrite Red interfaces is comparable or even cheaper then upper bracket AV processors, many of which have less than stellar noise and distortion measurements.