UE4 4.17 and a single audio source playing and I get crackling. I tried buffers up to 4096 in size and also increasing the number of buffers but wasn’t able to get clean audio. This is on a Samsung Galaxy S8.
Perhaps try 4.18? I noticed further improvements with it.
Sorry, my mistake. I actually meant UE4 4.18. That’s the version were I get the crackling. Also I have a custom USynthComponent with custom DSP as part of a plugin that works well on Windows but produces no sound in Android (and no error messages).
EDIT: Got it to work. Somehow I had forgotten to enable the new audio engine in the ini file. Sorry for the noise.