Let's look at this.

24 bits x 96kHz sample rate = 2304000 bps
Times 2 for stereo = 4608000 bits per second.
Times 8 for eight stereo channels = 36,864,000 bits per second
Time 2 for both directions = 73,728,000 bits per second.
Times 2 to double the speed in both directions = 294,912,000.

USB 2.0 bandwidth, 480,000,000 bits per second. Even with overhead, I've still got 100Mb/s to play with. So, basically, on a single USB 2.0 controller, I could probably run 8 stereo channels down, and 8 stereo channels up without any problem.

If you're going to do more than 8 by 8, you should probably be looking at the PCI or PCI-e interfaces.

This is why you aren't seeing any USB 3.0 audio interfaces.

Mac, can you check my math, make sure it's correct, please?

Gary

I'm blessed watching God do what He does best. I've had a few rough years, and I'm still not back to where I want to be, but I'm on the way and things are looking far better now than what they were!