Hi,
Some users with older iPad models running OS9 have experienced the same issue as you. The App can freeze in some specific cases. We are still working on a fix, and hopefully the next update pof the APp should solve that. Until then, try to free as much computing power as possible on your iPad: close most or all other Apps when running EarMaster (especially resource intensive ones), shut Bluetooth or Wifi, etc. I know it's not veery convenient, but like I mentioned, we're working on fixing this, so it's just a temporary workaround.