--- a/nagslang/sound.py	Sat Sep 07 23:38:26 2013 +0200
+++ b/nagslang/sound.py	Sat Sep 07 23:43:20 2013 +0200
@@ -4,17 +4,19 @@
 
 from nagslang.options import options
 from nagslang.resources import resources
-from nagslang.constants import FREQ, BITSIZE, CHANNELS, BUFFER
+from nagslang.constants import (
+    FREQ, BITSIZE, CHANNELS, BUFFER, DEFAULT_SOUND_VOLUME,
+    DEFAULT_MUSIC_VOLUME)
 
 
 class DummySound(object):
     def init(self):
         pass
 
-    def play_sound(self, name, volume=None):
+    def play_sound(self, name, volume=DEFAULT_SOUND_VOLUME):
         pass
 
-    def play_music(self, name, volume=None):
+    def play_music(self, name, volume=DEFAULT_MUSIC_VOLUME):
         pass
 
     def pause_music(self):
@@ -42,13 +44,13 @@
             sound = self._sounds[track_name] = mixer.Sound(track_name)
         return sound
 
-    def play_sound(self, name, volume=1.0):
+    def play_sound(self, name, volume=DEFAULT_SOUND_VOLUME):
         sound = self.load_sound(name)
         if sound is not None:
             sound.set_volume(volume)
             sound.play()
 
-    def play_music(self, name, volume=1.0):
+    def play_music(self, name, volume=DEFAULT_MUSIC_VOLUME):
         if not options.music:
             return
         track_name = resources.get_resource_path("music", name)