12-15-2016, 12:34 PM
Since the app/driver does not run in the kernel as real-time thread, lower than 512 is not possible indeed. It's still heaps better than the hundreds of milliseconds delay you get with Android though. One thing that may help is rooting the device and enabling the root tweak such that the USB audio thread can run as a real-time thread, but it's unfortunately still no guarantee.