Michael from TAAE took a look and caught a stupid malloc sizing issue I was making on [line 107](https://github.com/warpling/AudioEngineAndOpenEarsDemo/blob/master/AudioEngineAndOpenEarsDemo/ViewController.m#L107) (
self.streamFormat.mBytesPerFrame should really be
sizeof(float). It’s unclear why starting/stoping OE before using the buffers again exposed my mistake. Sorry for taking your time! This issue is closed.