Using multiple interfaces in ProTools - even identical interfaces possible?

[And#PT]

Thank you for your answers.

I have now tested several versions. ProTools 22.12 on macOS 10.15.7 and ProTools 24.3 on macOS 12.7.3. AVID writes at least MacOS 11.x as a requirement for Aux I/O. Aux I/O also works for me under MacOS 10.15. Anyway, I can do what I wanted with aux I/O (2 same interfaces). But it is still unclear to then identify the two identical interfaces in the Aux I/O window. In the Apple Audio MIDI setup, an additional name is automatically added after the respective interface. So it says UMC1820-1 or UMC1820-2. This addition does not exist in the ProTools Aux-I/O window. However, I cannot label this additional designation manually. The Aux I/O window only shows the same name UMC1820 twice. The assignment then seems random to me. I can't figure out which interface matches the respective interface in the Aux I/O window. This can only be done by testing the signal curve directly on one of the 2 interfaces. And that is exactly the same with PT24.3 / MacOS12 as with PT22.12 / MacOS 10.15.

Did I miss something or have I done something wrong? Or - if not - could I ask AVID here via this forum to include this option in a future update so that an additional name is added to two identical interfaces?

Andi

[cwsand]

Originally Posted by And#PT

Is it possible that ProTools (or the Mac already in its audio MIDI setup) can't handle it when two identical, identical interfaces are addressed? The same drivers are used. Does this bundling or combining of several interfaces into a new main device actually only work if you use different interfaces?

It depends on whether they're designed to work that way or not. I'm still using old Focusrite Saffire interfaces and using 2 Pro 40's together works fine. I'm currently using a Saffire 56 and Pro 40 on my main computer which is actually unsupported (due to bandwidth concerns I was told by Focusrite), but it works fine for me.

As far as creating an Aggregate Device, I could see how it might not work for more than one identical interface.

[Darryl Ramm]

Originally Posted by cwsand

It depends on whether they're designed to work that way or not. I'm still using old Focusrite Saffire interfaces and using 2 Pro 40's together works fine. I'm currently using a Saffire 56 and Pro 40 on my main computer which is actually unsupported (due to bandwidth concerns I was told by Focusrite), but it works fine for me.

As far as creating an Aggregate Device, I could see how it might not work for more than one identical interface.

I already addressed this, the names of devices, the fact that devices are the same exact model etc. does not matter a flying fark in Core Audio. Everything is managed internally via unique object IDs that sure work fine with multiple instances of the same model of device. Interfaces/drivers don't need to be designed to be aggregated in any special way to get the same models to aggregate. And there is nothing for a driver developer to implement or not to enable identical devices to aggregate. The issues is as always how well or not interfaces will behave once they are aggregated, and that is a different question than if identical devices can be aggregated.

[Darryl Ramm]

Originally Posted by And#PT

Did I miss something or have I done something wrong? Or - if not - could I ask AVID here via this forum to include this option in a future update so that an additional name is added to two identical interfaces?

Yep seems like you missed the flexible naming thing here. And kudos to the Avid folks who did it like this. On the Setup>I/O>{input, output} pages when you click on the [Aux I/O] button to add interfaces there are two columns in the dialog "Device Name" and "Display Name". You can click in the "Display Name" field for any device and edit the name/rename it, that name is what will appear in the Pro Tools I/O pages and track I/O selectors. You still need a way of identifying the ID/ordering of devices so you know what is what when you set this up, but that should be consistent, and you can always do a quick test to identify what device is what (and that is no harder than anything you would need to do for Aggregate I/O to identify exactly what device is what). At least that is how it is in 2024.3 and later (I can't recall if it was ever any different).

[Eric Lambert]

A friend is trying to do something similar. He has a Prism Titan and a Focusrite Scarlett and he's merely trying to find a way to get ProTools to use both interfaces. He tried creating a new Aggregate with both devices checked but that Aggregate isn't selectable as a playback engine in ProTools (maybe this is due to Focusrite's drivers, as Darryl mentioned?). However Logic does allow him to select it and it functions fine.

We're also looking at the option of using Aux IOs. I'm not sure which method will be best. I've always tried to avoid Aggregates since they have historically been buggy. The ultimate goal is to simply get those 8 channels of the Scarlett's A/Ds into PT. The Prism is already setup and operating perfectly, so just need to somehow add the Focusrite.

Neither of us have tried using multiple coreaudio interfaces simultaneously.

[Darryl Ramm]

Eric.

Is this a Titan running over DigiLink then trying to use CoreAudio to aggregate that with another device... I suspect Avid has crippled all paths to doing that. If you need to go that route then you would use the DigiLink Titan as the Pro Tools interface and add the Scarlett as an Aux I/O.

If you intend to use the USB port, make absolutely certain that's being used and it's not accidentally using a DigiLink CoreAudio connection. Especially if you don't have your own eyes on what is going on.

If that is done OK can you guys start a new thread and provide more info, maybe screenshots showing the aggregate in Audio MIDI Setup etc. What exact version of Pro Tools, macOS etc. Does an aggregate consisting of either device alone not work? Check nothing else is using these interfaces directly (I'd hope that not cause a problem). Most extreme case I can get you a tool to dump some CoreAudio internals.

Failing that you can ship the Titan to me and I'll take very good care of it

[Eric Lambert]

He's strictly using coreaudio -- no digilink.

But as it turns out he didn't have the Scarlett in standalone mode and apparently that was limiting some important functionality. He says that he now has it working, though not via Aux IOs. He's syncing the Scarlett to the Prism via spdif and sending audio from the Scarlett to the Prism via ADAT. He seems happy with this architecture.

So I guess it's not an Aux IO issue after all, though it is a "multiple interfaces in ProTools" issue so I guess it's not totally off-base.

[Darryl Ramm]

OK if he's using stand alone mode he's not relying on CoreAudio either. It's just emulating an ADAT preamp, as you say. And he can't use this as Aux IO either when in stand alone mode. OTOH what you folks are doing is a more reliable setup/better approach than using AUX I/O or Aggregate I/O. If there is an ADAT, or MADI, etc. connection option available between the boxes I'd always use that.

[cwsand]

Originally Posted by Darryl Ramm

I already addressed this, the names of devices, the fact that devices are the same exact model etc. does not matter a flying fark in Core Audio. Everything is managed internally via unique object IDs that sure work fine with multiple instances of the same model of device. Interfaces/drivers don't need to be designed to be aggregated in any special way to get the same models to aggregate. And there is nothing for a driver developer to implement or not to enable identical devices to aggregate. The issues is as always how well or not interfaces will behave once they are aggregated, and that is a different question than if identical devices can be aggregated.

Ok - I was talking about using 2 identical interfaces together without creating an aggregate.

[Eric Lambert]

Originally Posted by Darryl Ramm

OK if he's using stand alone mode he's not relying on CoreAudio either. It's just emulating an ADAT preamp, as you say. And he can't use this as Aux IO either when in stand alone mode. OTOH what you folks are doing is a more reliable setup/better approach than using AUX I/O or Aggregate I/O. If there is an ADAT, or MADI, etc. connection option available between the boxes I'd always use that.

Indeed, it seems like the better approach, not having to roll the dice with an aggregate.