Where are audio device files in OSX?
Here are some suggestions.

If you are talking about Hardware Abstraction Layer (HAL) devices, then the path is 

/Library/Audio/Plug-Ins/HAL/


By default there is one bundle there: on my Mac iSightAudio.driver, is the driver for the built-in webcam.

Other devices may use Kernel Extensions; bundles that end in .kext, are located in:

/System/Library/Extensions/