change default audio buffer size?

Is it possible to change the audio system’s default audio buffer size? And while I’m at it, is it possible to change the default sample rate?

Specifically I’m looking to change the buffer sizes in custom USoundWave classes. It looks like the buffer size is set in AudioCompress.h:

#define MONO_PCM_BUFFER_SAMPLES		8192

Is there any way to change this without building UE4 from source?