diff --git a/Demos/Device/AudioInput/AudioInput.txt b/Demos/Device/AudioInput/AudioInput.txt
index 36e71e9750..0b1ab8d7eb 100644
--- a/Demos/Device/AudioInput/AudioInput.txt
+++ b/Demos/Device/AudioInput/AudioInput.txt
@@ -66,5 +66,10 @@
  *    <td>Makefile CDEFS</td>
  *    <td>When defined, this alters the demo so that the half VCC bias of the microphone input is subtracted.</td>
  *   </tr>
+ *   <tr>
+ *    <td>AUDIO_SAMPLE_FREQUENCY</td>
+ *    <td>Descriptors.h</td>
+ *    <td>Gives the audio sample rate per channel for the audio stream, in Hz.</td>
+ *   </tr>
  *  </table>
  */
\ No newline at end of file
diff --git a/Demos/Device/AudioOutput/AudioOutput.txt b/Demos/Device/AudioOutput/AudioOutput.txt
index 0638c47f96..b59c2a8b49 100644
--- a/Demos/Device/AudioOutput/AudioOutput.txt
+++ b/Demos/Device/AudioOutput/AudioOutput.txt
@@ -84,5 +84,10 @@
  *    <td>When defined, this outputs the audio samples in mono to port C of the microcontroller, for connection to an
  *        external DAC.</td>
  *   </tr>
+ *   <tr>
+ *    <td>AUDIO_SAMPLE_FREQUENCY</td>
+ *    <td>Descriptors.h</td>
+ *    <td>Gives the audio sample rate per channel for the audio stream, in Hz.</td>
+ *   </tr>
  *  </table>
  */
\ No newline at end of file