by Y-my-R » Tue Sep 22, 2020 1:27 am
If I was you, rather than spending a lot of money upfront, I'd just start with what doesn't cost anything, and then take it step by step from there.
For a first step - just to make sure: Your D8B is booting up fully, and is passing audio, without problems or noises (e.g. the dreaded rail cap pulsing, etc.), correct? Before I'd do anything else, I'd make sure of that.
Next, I'd try it with the ProBox, because you already have it, and can test if that works, and if you like it. You don't need any additional MIDI connection to just use the D8B as a controller with the ProBox. Even if that's not how you are planning to use the D8B primarily, it doesn't cost anything to try because you already have everything that is needed.
There's more info over on the ProBox side of the forum, on how to set that up (incl. me, walking a few people through that). The ProBox manual is of course also useful.
With the ProBox alone, you can't use the D8B for audio at the same time (aside from some analog pass-through features in the monitor section). To be able to use both, you'll still need to get that DB25 switch (that was missing from your shopping list, to use the D8B as a mixer AND as a 24-channel controller at the same time).
But anyway, once you got it working with the ProBox, that's where I'd disconnect the DB25 connector from the ProBox again, re-connect the DB25 between the D8B console and the rack unit, and start setting it up as a mixer.
For that, I'd first set the D8B up with whatever audio interface it is, that you currently have. Just to get your feet wet, and so that you know for sure that the D8B is what you want in your setup.
If you don't have a word clock out connector on your current soundcard, then you can just use the D8B as word clock master, connect either one of the ADAT outputs on the D8B to your ADAT input on your soundcard, and set the soundcard to sync to the digital input you just connected.
If you don't have an ADAT port on your current soundcard, then you can use the S/PDIF out on the D8B, and connect it to the S/PDIF in on your soundcard... but then you'll only transfer 2 channels digitally, instead of 8. The D8B should then still be set to Word Clock master, and your soundcard to Word Clock slave (from incoming S/PDIF).
If you run into any problems with that, you would run into the same problems once you bought a bigger audio interface. So, this should be good practice, and a preparation for "upgrading" later.
For the D8B to receive audio, pass it through the D8B's FX, and send it back out to an ADAT (or analog) output, this is all you need. The transport buttons will not work yet, and the time display will always show 00:00:00:00:00, but at least you get an idea how the routing works, and can explore the desk a bit.
Once you got that working, that's where I'd add a MIDI interface, so you can get the transport buttons working, and the D8B chase the time-code from the computer. But I wouldn't even buy the MIDI interface, until you reached this point.
About MIDI "cables" - I used to work at M-Audio Tech Support many years ago, so I know that one works. That is, as long as you have the 'newer' version that is class compliant (i.e. works with Windows/Mac built-in drivers, without requiring to install any). The technology in the Uno is no different than in the 2x2 or 2x4, etc. - so, it's not really "cable" vs. interface. If you buy some super-cheap off-brand "cable" interface, you could run into problems, sure. And personally, I'd just stay away from anything made by Behringer... I had a couple of bad experiences with their gear, and would not be surprised if their MIDI interfaces don't do SysEx or other "advanced" MIDI stuff.
As for the new audio interface... sure, that one looks like it should work, but again, I'd get everything I'm mentioning above working in the order described. Otherwise, you might end up with a collection of paper weights, if it doesn't work in the way you'd like. And you can "test" how it works, and what's necessary to configure it, without spending big money upfront.
Not to discourage you, but there have been a few people on this forum, who gave up on the whole thing, after a few rounds of troubleshooting. So, you first want to be sure that this setup really is for you.
The only thing about that audio interface is, that I'd expect it to deliver around 10-12 ms of latency, round-trip. Possibly worse, when the Mac Mini runs hot, and it is likely to run hotter, when you're having it process more audio streams (i.e. passing 24 channels of audio via ADAT through the interface). If that happens, you'll have to increase the buffer size, which increases the latency... and then you are getting into an area, where you might not be happy about the long delay, and will have to think about getting an eGPU (external graphics card + enclosure) for your Mac Mini.
Btw., is the Mac Mini you have a Thunderbolt model, or an older model that still had FireWire? I think you said you still use a FireWire interface, right? If so, you can't use an eGPU, and would need a new computer... and then I'd rather look at an iMac, because the built in video card is better and doesn't overheat the rest of the computer. Or a new Mac Pro... but that's crazy expensive.
I won't comment on music shared, and if that's achievable via plug-ins on the computer or not. I'm typing messages that are too long to begin with, and don't want to start a philosophical discussion on top of it. Then it would REALLY get too long.
...oh, last note... a Big Ben or other Master Clock is another thing that I wouldn't buy from the get go. Make sure you get it all working first, and see if it's enough for your purposes (e.g. after adding the audio interface you want). Adding an external Master Clock later, is easy to do. And again, if you only need to sync the D8B and the computer together, a simple word clock cable (and possibly a word clock terminator on the computer end, depending on if your audio interface internally terminates or not) is all you need to get started.
Anyway... again, try with the ProBox first, since you don't need any new hardware for that. If you get stuck somewhere, after looking for instructions in the manual and on the ProBox side of the forum, post again with details what you did and what doesn't work, and we'll pick it up from there, again.
Best of luck!