diff --git a/mopidy/core/playback.py b/mopidy/core/playback.py
index bf645227..097a9401 100644
--- a/mopidy/core/playback.py
+++ b/mopidy/core/playback.py
@@ -102,7 +102,9 @@ class PlaybackController(object):
             self._volume = volume
 
     volume = property(get_volume, set_volume)
-    """Volume as int in range [0..100] or :class:`None`"""
+    """Volume as int in range [0..100] or :class:`None` if unknown. The volume
+    scale is linear.
+    """
 
     def get_mute(self):
         if self.mixer:
diff --git a/mopidy/mixer.py b/mopidy/mixer.py
index 34e006a4..3c8c7639 100644
--- a/mopidy/mixer.py
+++ b/mopidy/mixer.py
@@ -32,7 +32,7 @@ class Mixer(object):
 
     def get_volume(self):
         """
-        Get volume level of the mixer.
+        Get volume level of the mixer on a linear scale from 0 to 100.
 
         Example values: