Hi everyone !
I have the UR22 & the HD500X (that i use for guitar effect).
In Cubase 8 pro i would like to use both at the same time but i don’t know how !
(please don’t tell me it’s impossible because it’s impossible) 
As i said i want to use the HD500x for guitar & use the UR22 to hear my music (the phones) when i work on Cubase …
I also use UR22 for voice ( i prefer) … but how can get these 2 interface work at the same time : IS IT THE BUS stuff ?
Thank you !
Cubase itself can only handle one interface. The “ASIO4ALL” driver (freeware) should be able to handle two interfaces. But this should be not very stable. I have never tried this. Some higher class interfaces can be cascaded (e.g. by ADAT connection), so that one interface driver provides the in- and output channels of the other ones. But this is not possible with the UR22
Actually only one ASIO driver, so that some OEMs, like RME, provide drivers that can cope with multiple devices from the same family of models. For example, Cubase can handle both my Fireface 400 and 800 with their common Firewire driver.
Some others may be able to do the same.
On the Windows side, it almost always better to use the ASIO drivers designed for the interface, as the lowest latencies and full capabilities are available, in which case devices from different OEMs will NOT work together because they require different ASIO drivers.
On the Mac side, audio interfaces can be aggregated, but I have no idea how it works, or if it works with the UR22 and HD500X.