diff --git a/include/nuttx/audio/audio.h b/include/nuttx/audio/audio.h
index d70581e7e5e..ff19d0a9a24 100644
--- a/include/nuttx/audio/audio.h
+++ b/include/nuttx/audio/audio.h
@@ -356,7 +356,10 @@ struct audio_caps_s
   uint8_t ac_len;           /* Length of the structure */
   uint8_t ac_type;          /* Capabilities (device) type */
   uint8_t ac_subtype;       /* Capabilities sub-type, if needed */
-  uint8_t ac_channels;      /* Number of channels (1, 2, 5, 7) */
+  uint8_t ac_channels;      /* Number of channels (1, 2, 3, ... 8) */
+  uint8_t ac_chmap;         /* Channel map, each ch for each bit,
+                             * zero means don't care */
+  uint8_t reserved;         /* Reserved for future use */
 
   /* Audio data format(s) for this device */