and here's the output from a good unit. You can see the mics at device 24:[0-0] and 25:[0-1]

0: [ 0] : control
16: [ 0- 0]: digital audio playback
17: [ 0- 1]: digital audio playback
24: [ 0- 0]: digital audio capture
25: [ 0- 1]: digital audio capture
33: : timer