diff --git a/src/polyp/channelmap.h b/src/polyp/channelmap.h
index 76380b5f2..0fd1e5933 100644
--- a/src/polyp/channelmap.h
+++ b/src/polyp/channelmap.h
@@ -137,7 +137,9 @@ pa_channel_map* pa_channel_map_init_mono(pa_channel_map *m);
 /** Initialize the specified channel map for stereophonic audio and return a pointer to it */
 pa_channel_map* pa_channel_map_init_stereo(pa_channel_map *m);
 
-/** Initialize the specified channel map for the specified number of channels using default labels and return a pointer to it */
+/** Initialize the specified channel map for the specified number
+ * of channels using default labels and return a pointer to it.
+ * Uses the mapping from RFC3551, which is based on AIFF-C. */
 pa_channel_map* pa_channel_map_init_auto(pa_channel_map *m, unsigned channels);
 
 /** Return a text label for the specified channel position */