Adding AES to the MTRX Studio with a 192 Digital IO

[scottmckay]

I use the AES outputs of a 192 Digital for monitoring in 7.1.4 using bass management from the MTRX Studio in the following DigiLink chain:

HD Native Thunderbolt Box -> MTRX Studio -> 192 Digital.

Word clock is set up using loop sync in and out of both interfaces. Sync term @75 ohm.

I use the MTRX Studio in DigiLink Pri/Pri mode to gain access to the 192 via the DigiLink 2 port in the DADman monitor profile, and I can combine the AES outs with analog outs in monitor sets and fold-downs with eq, delay, and bass management. It's a really flexible setup and everything does technically work. However, I have to jump thru so many hoops to get playback from MacOS applications other than Pro Tools that it is driving me nuts.

CoreAudio with other Avid HD hardware has been relatively straightforward-ish in comparison with the AVID Audio Server app, but with the MTRX series interfaces everything is greyed out and points you to DADman. Ok, fine, but after many tries, it doesn't seem that changing the sample rate in DADman has much of an effect on the 192. The output LEDs flash but the sample rate stays the same.

Ok, so why not try Audio MIDI Setup? Well, in AMS, the Clock Source option is simply not visible, however, there is a magical circumstance that will coax it from its hiding place:

1. In Audio Midi Setup, ensure the desired sample rate for coreaudio playback is selected.
2. Open DADMan and change DigiLink mode to Pri/Exp.
3. Open Pro Tools and confirm presence of 192 interface in hardware setup. Check sample rate on 192. If sampe rate differs from desired, open a session at desired sample rate. Close Pro Tools.
4. After closing Pro Tools, a Clock Source option will now be visible in Audio Midi Setup. Toggle the Clock Source to select 192 Internal, and then back to select MTRX Studio Internal. If the 192 stays in loop mode after this you should be good.
5. In DADMan change digilink mode to back to Pri/Pri to get your monitoring back.
6. Cross your fingers.

I have to perform this dance every time I start the computer or change sample rates. It works ok after the ritual, but it is not ideal.

Does anyone else have the same setup? What is your experience?

Does anyone have ideas how to make this better?

If I put the 192 on the DigiLink port 2 of the HD Native Thunderbolt box, I lose bass management/monitoring options.

[BScout]

Your "method" is not one expected. It's a kludge hack. The secondary port on the MTRX Studio is really meant for allowing it to have 64 channels in Pro Tools. Or, at worse, expansion. The 192 is not meant to run "stand alone."

So what you've done is made the MTRX Studio the "host" to the 192 when in PRI/PRI. When in PRI/EXP, the MTRX Studio and 192 are talking to the HDX card (or Native TB Box in your case) as the "host". Which is the right way it is supposed to work. Avid Core Audio/Audio Server talk through the HDX card/TB Box and only to what is connected. Only to the clients. In PRI/EXP mode, both the MTRX Studio and 192 are clients (communication is passed through.) In Pri/Pri, only the MTRX Studio is the client.

In essence, you've severed that connection to the 192 when you put the MTRX Studio in PRI/PRI.
If your only issue is clocking, don't do loop sync (which is a pointless endeavour with the MTRX units anyway.) Run clock out from the MTRX to the 192 regular wordclock in on a BNC T connector. Then terminate the other side of the T. Set the 192 to listen to external wordclock (not loopsync!) from within Pro Tools. Then, if the 192 is running in a pseudo-standalone mode, it has a chance of following the MTRX.

But in the end, you've shoved a square peg into a round hole and are asking how to get unstuck. Well...

[scottmckay]

Originally Posted by BScout

Your "method" is not one expected. It's a kludge hack. The secondary port on the MTRX Studio is really meant for allowing it to have 64 channels in Pro Tools. Or, at worse, expansion. The 192 is not meant to run "stand alone."

So what you've done is made the MTRX Studio the "host" to the 192 when in PRI/PRI. When in PRI/EXP, the MTRX Studio and 192 are talking to the HDX card (or Native TB Box in your case) as the "host". Which is the right way it is supposed to work. Avid Core Audio/Audio Server talk through the HDX card/TB Box and only to what is connected. Only to the clients. In PRI/EXP mode, both the MTRX Studio and 192 are clients (communication is passed through.) In Pri/Pri, only the MTRX Studio is the client.

In essence, you've severed that connection to the 192 when you put the MTRX Studio in PRI/PRI.
If your only issue is clocking, don't do loop sync (which is a pointless endeavour with the MTRX units anyway.) Run clock out from the MTRX to the 192 regular wordclock in on a BNC T connector. Then terminate the other side of the T. Set the 192 to listen to external wordclock (not loopsync!) from within Pro Tools. Then, if the 192 is running in a pseudo-standalone mode, it has a chance of following the MTRX.

But in the end, you've shoved a square peg into a round hole and are asking how to get unstuck. Well...

Thanks BScout.

I tried clocking from normal WC with less reliable results, but I wasn't using the termination you're suggesting so I will try that.

This kludge hack is 1/10 the price of the "right way" to do it, but is turning out to be easily over 10x more annoying.

[scottmckay]

Incremental progress.

I can report that now after switching from using Loop Sync to now sending WC Out from the MTRX Studio to WC In on the 192 with a 75-ohm terminator on a T-connector as you suggested, when PT is closed, WC source and sample rate are maintained and CoreAudio now resumes the ability to play back. It will even work after a reboot, although WC source is missing in AMS after rebooting. No real surprise there but it does continue to work regardless.

I still have to toggle pri/exp and launch and close PT whenever I want to change sample rates, but when the Audio Midi Setup sample rate matches the PT sample rate, it's actually much less of a headache now. For example, if I am working in 48khz all day, as I often do, in theory I wouldn't have to touch it, although trusting it is another story.

I'm still a bit curious about a Dante solution, although that's another headache in itself. From my limited experience there, I couldn't get Dante devices to follow the MTRX sample rate changes automatically, so manual sample rate changes are still required. The fact that there is more latency is not exciting either, although I didn't find it very noticeable. It also didn't exactly seem rock-solid, as I found Dante Controller to be quite clunky, and heard some clicks and pops at times when Dante Controller reported everything to be fine.

[BScout]

DVS does not follow sample rate. But, if you grab an AVIO (and only need 2 channels) that will follow limited sample rate.

Other Dante devices will follow sample rate. It's pretty much a (stupid) limitation on DVS not to follow sample rate making you have to manually change it.

Make sure your Dante network is set to have the MTRX as the master clock (you have to designate it as such -- otherwise it auto-picks)

[scottmckay]

Originally Posted by BScout

DVS does not follow sample rate. But, if you grab an AVIO (and only need 2 channels) that will follow limited sample rate.

Other Dante devices will follow sample rate. It's pretty much a (stupid) limitation on DVS not to follow sample rate making you have to manually change it.

Make sure your Dante network is set to have the MTRX as the master clock (you have to designate it as such -- otherwise it auto-picks)

My experience was actually with an AVIO not following the sample rate of the MTRX as preferred leader. I did have a DVS on the Dante network, and was surprised to learn about that limitation already, albeit the hard way (I agree, utterly moronic).

I was a bit more concerned about the AVIO not following given the application (sending AES to speakers). Do you think the existence of a DVS node on the network caused sample rate following in general to fail?

Moreover, given that many more elegant solutions (Focusrite D16R, etc) suffer from low availability and higher prices, would it be a bad idea to have 6 AVIO's for 12 channels of AES for monitoring in 7.1.4? (Assuming they all should follow sample rate changes and I was just doing something wrong or DVS was causing the whole network to be stuck in manual mode). I'm skeptical that the latency will be exactly identical to each AVIO.

[BScout]

I wouldn't go with that many AVIOs for that kind of simultaneous channel count. I'm surprised the AVIOs don't follow clock since they do have a chip.
A Mutec MC-4 is $800.
6 x AVIO AES is $1200.

Any day of the week I'd take the ADATs of your MTRX Studio and use them with the Mutec-4 to get AES. (also, the Mutec can SRC)

[scottmckay]

If I'm not mistaken the Mutec box can only do 8ch of aes so I would need 2 of those (or some other 16-ch solution) to service all 12 speakers.

And even then I would be limited to 48khz.

[LDS]

The AVIOs don't follow sample rate changes. At least that was the word from Audinate 3 years ago or so when I asked about it.

I'm sure the lack of AES is a frustration many people share about the MTRX Studio and the most recent DAD boxes. The Focusrite box is a neat solution, but is ridiculously priced. The DAD DX-32 is even neater, as it will tie straight into the DAD environment. It might also be cheaper than the Focusrite and offer more I/O (you'll have to confirm whether the price includes the Dante expansion card). Often you can grab RME 8 channel format converters, or Euphonix or Otari format converters for quite cheap on eBay too.

Depending on what other types of I/O you need, the full MTRX with AES as standard plus some expansion cards may well be the best/cheapest solution.

[LukeHoward]

Originally Posted by BScout

Your "method" is not one expected. It's a kludge hack. The secondary port on the MTRX Studio is really meant for allowing it to have 64 channels in Pro Tools. Or, at worse, expansion. The 192 is not meant to run "stand alone."

I'm still kind of amazed this even worked...