Multiple MOTU interfaces. What's the trick?

[cleantone]

It's been ages since I've used more than one piece of FW Hardware. I'm finding myself needing to today. I used to use Digital Performer back 20 years ago and you could daisy chain devices and they would all show up in the DAW. I assumed this would be the case today in modern DAW. Anyway I have two 896HD's and an 8pre. I need to record 24 tracks of optical ADAT. 896 #1 is connected via FW400 to 800 to my iMac. 896HD 2 is daisy chained then to the 8pre. I have all MOTU's showing up in MOTU Audio Setup and renamed the ADAT Optical inputs adding A, B, C in banks of 8 to each device. I also set device B and C to derive clock from device A. The clocks sync on the interfaces. In Reaper I can connect to anyone device and the inputs show up labelled with the A, B, or C but I can't figure out how to show all three at once. Is this even possible? If not does anyone have an alternate recording software I can easily record hours of 24 track 24/48 audio?

[cleantone]

Ah! It’s called aggregate device and it’s now in MacOS Audio MIDI setup panel. Once that is done I can set all devices to get clock from the ADAT. It appears to be working fine. Recording now!

[cyrano]

As far as I can remeber, it's always been in Audio/midi setup. But, yeah, it's a bit of a strange split, with Sound being in System preferences.

[mschnell]

Originally Posted by cleantone

Ah! It’s called aggregate device and it’s now in MacOS Audio MIDI setup panel.

AFAIK, such option is not available in Windows with ASIO.

I understand it should be available now with WASAPI.

Did anybody get a "native" (!) WASAPI system running ? (I suppose this needs dedicated WASAPI drivers for the hardware. Do those exist ? )

Moreover I understand that aggregating requires re-sampling which might be not a good thing. It would be better to use a hardware word clock connection between the A/D boxes, but of course this is not supported by many of them.

-Michael

[Mcgiver69]

Originally Posted by mschnell

AFAIK, such option is not available in Windows with ASIO.

I understand it should be available now with WASAPI.

Did anybody get a "native" (!) WASAPI system running ? (I suppose this needs dedicated WASAPI drivers for the hardware. Do those exist ? )

Moreover I understand that aggregating requires re-sampling which might be not a good thing. It would be better to use a hardware word clock connection between the A/D boxes, but of course this is not supported by many of them.

-Michael

You can do it using Asio4All but both devices should be connected using SPDIF or ADAT (Optical).

https://www.youtube.com/watch?v=h9Zva--QVVQ

https://www.youtube.com/watch?v=EczMDEFZdRM

[cyrano]

I'm sure I've done it over USB, with some ordinary interfaces in the past. And that's on Windows and Linux. Windows remains a hairy beast. Linux might require a bit of experimenting.

I've seen arrays of six or seven audio interfaces under Linux. Preferably the same interfaces, or at least comparable. Same number of channels, same SR, same bit-depth settings. Of course, ADAT and spdif might be easier, as these comply to a standard that is widely accepted. Besides, PCI ADAT interfaces are usually higher end, with better re-clocking.

It will not work with some interfaces. Don't know if that's hardware or software related.

On MacOS, it's easy to try out and >90% of interfaces I've encountered work in aggregation. The only manufacturer that I know of that explicitly doesn't support aggregation, is Tascam. Despite that fact, some Tascam interfaces can be aggregated without any problems.

You also have to take into account that, if you aggregate 3 or more interfaces with 8 channels over USB, the bandwidth is not enough for 96 kHz, let alone 192...

[serr]

This DID used to be done by the DAW app way back in OS9 days. I remember doing that with early Digital Performer too. Since OSX this is SOP to make and control aggregate devices with the OS utility app. (Can't say what the timeline was in Windows land.)

Reaper does have a 'legacy' feature to control this all from the DAW (which is noted as "not recommended").

I suspect the thing that throws many people is clocking. It's kind of like a separate system you need to manage in addition to the aggregate device config and the data connections (firewire, USB, TB). With just a single interface, the default of internal clock takes care of you and you can be oblivious to even what a sample rate is. Connect that 2nd digital device and suddenly you need to control all this!