My 2012 MBA couldn't connect w/ USB 3.0 to a new RME UCX mixer. According to various discussion threads on the internet, Apple's implementation of USB 3.0 causes trouble for various audio devices. I thought -- in theory this seemed sensible -- that using a Thunderbolt to Firewire adapter would allow a connection. The adapter I ordered arrived today and I can report it doesn't, at least not with the UCX. No connection and, moreover, some strange pulsing feedback in my headphones. But just for the heck of it I thought perhaps a USB 2.0 hub might coax the MBA into talking with the UCX. I tried it, with a Belkin mini hub, and I'm happy to report that this works. Your mileage may vary.