For a quick test, I played MidiBand from my Casio PX330 fitted with a duplex bluetooth midi interface. Totally wireless both ways between the Casio and the IOS device. MidiBand immediately bagan to play but the sounds were coming from the Casio. That was when I remembered MidiBand doesn't come with a built in sound set. I routed midi out to the Roland Sound Canvas app. Now with midi going both to the Roland app in the tablet and to the Casio both were playing exactly the same thing. Kind of neat.

MidiBand is much more complex, in a good sense, for its price. I need to explore more. It seems to have quite a few features. This is another reminder that I need to use what I've got now....