Audio Hardware Tab: Contains settings for your Audio Device and also includes a Test Tone generator
Driver Type- allows you to select a sound card diver model to use for playback
Audio Device- choose the output device/soundcard you want RX to use for playback
Buffer Size- the total playback buffer size. In general, lowering these buffer sizes will increase CPU needs. Raising buffer sizes will lower CPU cost. It's worth exploring these ranges to find values that work best on your system.
Num Buffers- number of playback sub-buffers
Channel Routing- For ASIO and Core Audio drivers, click this button to choose which output channels RX uses
Close when not in use - Auto-close the audio device when playback stops