One caveat on this solution do NOT have the keyboard and interface going into the same USB hub if it's unpowered. In a bedroom scenario, you don't need the DI box just take your two TS cables from the interface, and put them straight into the mixer. If you're playing on stage, and you're quite a distance from the mixer, this is how you'd do it. The diagram then shows the interface going through a DI box to connect to the mixer. The Mac then connects to the interface using USB (again, fine). The first line shows a keyboard connected to a Mac using USB (this is fine, and the current way of doing it).
