Mmmh. I've got Vista,7 & 8 machines. All of them support multiple USB audio interfaces simultaneously. I don't understand your issue.
Ah. Sorry. Now I do. You want to send a single output from one application to 2 separate interfaces? Yes? That would be a little more problematic. Depending on the specification of your existing gear.
The MOTU Ultralite, NI Audio 2 and M-Audio Fast Track Pro can all do what you would want but that's because they support multiple stereo programs output on multiple channels via ASIO drivers. I'm not sure off hand if I could feed the same output from, say, foobar to two different devices without looping the signal back and therefore getting latency issues.
Anyway the simple answer to your question is yes you can output the same signal to 2 devices provided you have the right kit.
Ah. Sorry. Now I do. You want to send a single output from one application to 2 separate interfaces? Yes? That would be a little more problematic. Depending on the specification of your existing gear.
The MOTU Ultralite, NI Audio 2 and M-Audio Fast Track Pro can all do what you would want but that's because they support multiple stereo programs output on multiple channels via ASIO drivers. I'm not sure off hand if I could feed the same output from, say, foobar to two different devices without looping the signal back and therefore getting latency issues.
Anyway the simple answer to your question is yes you can output the same signal to 2 devices provided you have the right kit.