Selecting Audio Device

Without any configuration CornerStone will use the default audio device that your computer has. Quite often it is necessary to change the device, for example if you are using a multi-channel sound card, which is not the default sound card.

The sound card selection happens with the use of environment variable RESONANT_DEVICE, that is set to the name (or index number) of the desired audio device.

To select the audio device you first need to know what are the available devices. For this, one can use a utility application ListPortAudioDevices that simply lists the available devices:

 ./ListPortAudioDevices.app/Contents/MacOS/ListPortAudioDevices 
 API 0: Core Audio
 Audio device 0: [Built-in Microphone], channels = 2-0, API = Core Audio
 Audio device 1: [Built-in Input], channels = 2-0, API = Core Audio
 Audio device 2: [Built-in Output], channels = 0-2, API = Core Audio
 Audio device 3: [Saffire 6USB], channels = 2-4, API = Core Audio

To select the Saffire sound card from the above list there are two options: The RESONANT_DEVICE could be set to "Saffire 6USB" (which is the name of the device) or "3" (which is the index number of the device). Usually the device name is more practical choice since the order of the devices may change when the computer is rebooted.

Resonant will automatically use all available output channels, so if your sound card has 16 output channels, the 16 channels will be used.

Unfortunately some (Windows) sound cards report that they can provide over 65000 output channels, which appears to be a bit of an exaggeration. In these cases the actual number of audio channels will be set to 2, since it is practically guaranteed that any hardware can play back at least 2 channels.