A mixer with USB should act just like a USB interface with the added mixer feature(s).
Herb uses a Focusrite interface .. OP is using a mixer.

Either way, there will a way to record vocals without the backing tracks .. Focusrite just uses a software mixer (or setting) to accomplish this where the OP uses a hardware mixer, but in the end his USB to the computer should be able to record vocals separate. Looks like Charlie went as far as to investigate the mixer for him just above Herb's post.
Nice.

Hope it results in 'real-time monitoring', with no latency.


I do not work here, but the benefits are still awesome
Make your sound your own!