Each Oculus device type has different audio capabilities.
The Oculus Rift has a built-in DAC (audio over USB connected to the headset) and ADC (for microphone). The audio subsystem is class compliant and supports Windows, Mac, and Linux. An Oculus HMD for PC has integrated headphones and a microphone.
Oculus Android devices support 16-bit, 48 kHz sound. Headphones can be used, but aren’t required.
Mobile performance is lower than desktop PC performance, so try to minimize the number of audio sources.