Using 2 interfaces in one Pro Tools Session

[pscott57]

In a recent post and with the help of those participating, I was able to get my old Digi 003 to work again with Pro Tools (Artist version 2023.12.1) on my old iMac (Monterey OS version 12.7.3).
My main interface is a Focusrite Scarlett 18i20 (3rd generation).
I can have both interfaces powered up with no issues. But I cannot use both sets of inputs at the same time.

Some scenarios:
1) If I power up the Digi 003 first, then the Scarlett, then launch Pro Tools and set the Scarlett as the Playback Engine, I can use many of the functions on the Digi 003; transport, solo, mute, faders, the display. But I cannot use its I/O.
2) If I fire up the Scarlett first, then the 003, set the Scarlett as the Playback Engine again, the 003 doesn’t function well.
3) If I set the 003 as the Playback Engine, it works fine, but the Scarlett doesn’t do much.
4) If I power up either one on its own, they both work fine.

So, my question is simply this: how can I make the inputs from both units available within the same session? Or is it possible?

>>I have tried a couple of Aggregate configurations, but perhaps I don’t understand how to set them up correctly.
I have also read that Aggregates don’t always work correctly for something like this.<<

Having both units working within the same session will give me two things:
1) 16 inputs for a decent setup for a small band with drums, bass, guitar, vocals, etc.
2) No need to fork over the bucks for another interface that would work with one or the other, thus making good use of perfectly serviceable devices without having to throw them out as e-waste.
I also have an M-Audio Firewire 2626 interface that I can no longer use, even with the Digi003.

I know that many folks out there have a similar arsenal of obsolete equipment. It’s sad that so many companies don’t support older equipment, but it’s obvious it’s done to sell more products.
OK I’ll get off the soap-box …

[its2loud]

1. Use the ADAT out of the 18i20 into the 003 = more inputs
2. Use Aux IO to use the 18i20 as another interface.

[pscott57]

Tried the ADAT both ways: out from Scarlett, in to 003, then out from 003 to Scarlett . No luck. (Will try again)
Any clarification for using Aux I/O?
Thanks for your reply!
Paul

[Darryl Ramm]

I would focus on just getting ADAT to work, this is the "right" way to do this. AuxIO may presents more issues with incorrect timing/latency and other things than it is worth.

Since the 003 has no stand alone mode you cannot use that as an ADAT preamp, and that has been covered in hundreds of posts on DUC over the last decade or so. So you would need to use the 003 as the interface in Pro Tools and set up the 18i20 in standalone mode and use it as an ADAT preamp.

All problems beyond that are likely to have simple causes:

Not understand ADAT and sample rates etc. And since the 003 does not support SMUX it's 44.1 or 48 kHz only.

Not connecting ADAT out to ADAT in.

Not make sure both devices are running at the session sample rate.

Not make sure clocking is set correctly. WC is always good, but you need to live with the limitations of the 18i20 only having WC Out so needing to be the clock master.

Not defaulting the I/O if the ADAT ports are not showing up. etc.

--

The 003 is an old interfaces + control surface showing its age and lacking some stuff (like SMUX and any stand alone mode... perennial issues with the 003 design), you have to decide if all this messing around is worth it.

[pscott57]

Thank you Darryl Ramm
Sample rates match ...
ADAT connections are correct as per "its2loud" ...
Word Clock on Scarlett is Master ...
3 things:
Should ADAT connection be Out to 003 from Scarlett, or vice versa?
By 'standalone mode', do you mean NOT connecting Scarlett via USB to the computer?
I don't understand "Not defaulting the I/O if the ADAT ports are not showing up. etc."

Yes, I know how old the 003 is, but it works well, and I really can't afford to expand my studio much. If I can get both units to work together, the attempt is worth it.
If I can't, then so be it.
That I have the thing up and running means it might be helpful to someone else, so I can either sell it or even donate it ...

Thank you!!
Paul

[Darryl Ramm]

By stand alone mode I mean that both these boxes are interfaces, they are not ADAT preamps. Normally you would use an ADAT preamp to add inputs to an interface that has an ADAT in, and inside those preamps they just connects up the mic inputs via a preamp (or maybe line inputs) to their ADAT out. While an interface box does not do that normally, many interfaces nowadays have a stand-alone mode where they can emulate an ADAT preamp--the 003 cannot do that, the 18i20 can.

You need to read the manual for the 18i20 that will explain how to do this. Without doing this you will of course get no signal out of it's ADAT out into the 003 being used as an interface.

Then the 18i20 ADAT output first ADAT Out port needs to be connected to the (only) ADAT In port on the 003. And your sessions need to be at 44.1 or 48 kHz.

Since I like using Word Clock/having everything possible wired up for WC I would normally run a WC coax cable from the 18i20 WC Out to the WC in on the 003 and set the 003 to clock from that. Follow directions for WC use in all the documentation, use a 75 ohm digital/video not analog audio coax. Or just set the 003 to clock from it's ADAT input.

[pscott57]

Thanks again!
I'll continue to play with this. You've been a great help, Darryl.

Paul

[EGS]

Originally Posted by pscott57

... how can I make the inputs from both units available within the same session? Or is it possible?...

^^^Darryl laid it all out for you!

FWIW, here's how I'm doing it with my gear. I'm using a Presonus 2626 as my audio interface. I originally got the 2626 as an upgrade from my previous interface, a Focusrite LS56. The LS56 does have a standalone ADAT slave mode available, essentially turning it into a 8-ch mic-pre expander box (thank you Focusrite). The LS56 slaves to the 2626 via WC, and sends 8 channels @ 48k to the 2626 adat in's. Works great!

[pscott57]

Thanks, Darryl
Had to order up a BNC cable for WC (and a 75 ohm terminator). Took a long time to get here, but that was the last link in the chain I needed.
Thanks, "EGS", for your encouragement.

Paul