Maybe I'm just googling the wrong thing but what's Unreal's default audio sample rate? 44.1kHz or 48kHz? Silly simple question but thanks for helping out!
Unreal Engine 4 currently supports importing uncompressed little endian 16 bit wave files at any sample rate (see the chart below). For best results, it is recommended that sample rates of 44100 Hz or 22050 Hz be used.
Here is the link to the documentation if you'd like to read more: https://docs.unrealengine.com/latest/INT/Engine/Audio/Overview/index.html