Why can't we use four D2's but we can use two D2's with an S8.

What's the difference? I want to use an external audio interface with 4 D2's. I've been told it's a bandwidth issue but that doesn't make sense if the S8 + D2's works. Can someone please explain?

 

Probably because they are designed to control either decks A+C or B+D. Decks C and D cannot be the primary decks as far as I am aware.

 

There's only so much data you can transmit on the USB 2.0 interface, whereas USB 3.0 can transmit at least 10x the amount of USB 2.0, but not every new laptop out there has USB 3.0 ports built in as standard. Perhaps with a future Z2 Mk2 or Z4/Z6, they'll have an USB 3.0 hub built in to enable 4 D2s to be run simultaneously without any bandwidth issues. At least, if I was NI, that's what I would do.

Ideally, the D2 should have had a 3.0 hub built in as well from the beginning, but a bit too late now. A smaller X1-sized D1 must have such a port to enable reliable powering of the screen alone instead of a 2.0 one, IMO, in order to also set a standard going forward for new NI equipment.