diff --git a/modules/juce_audio_devices/audio_io/juce_SystemAudioVolume.h b/modules/juce_audio_devices/audio_io/juce_SystemAudioVolume.h
index 9e5390ac82..dd56ec5416 100644
--- a/modules/juce_audio_devices/audio_io/juce_SystemAudioVolume.h
+++ b/modules/juce_audio_devices/audio_io/juce_SystemAudioVolume.h
@@ -28,7 +28,7 @@
 
 //==============================================================================
 /**
-    Contains functions to control the system's master volume
+    Contains functions to control the system's master volume.
 */
 class JUCE_API  SystemAudioVolume
 {
@@ -53,6 +53,7 @@ public:
     static bool JUCE_CALLTYPE setMuted (bool shouldBeMuted);
 
 private:
+    SystemAudioVolume(); // Don't instantiate this class, just call its static fns.
     JUCE_DECLARE_NON_COPYABLE (SystemAudioVolume)
 };
 
diff --git a/modules/juce_audio_devices/juce_audio_devices.cpp b/modules/juce_audio_devices/juce_audio_devices.cpp
index cc16c0858d..d7caabb3f8 100644
--- a/modules/juce_audio_devices/juce_audio_devices.cpp
+++ b/modules/juce_audio_devices/juce_audio_devices.cpp
@@ -236,9 +236,9 @@ namespace juce
 
 #if ! JUCE_SYSTEMAUDIOVOL_IMPLEMENTED
  // None of these methods are available. (On Windows you might need to enable WASAPI for this)
- float JUCE_CALLTYPE SystemAudioVolume::getGain()              { jassertfalse; return 0.0f; }
- bool  JUCE_CALLTYPE SystemAudioVolume::setGain (float gain)   { jassertfalse; return false; }
- bool  JUCE_CALLTYPE SystemAudioVolume::isMuted()              { jassertfalse; return false; }
- bool  JUCE_CALLTYPE SystemAudioVolume::setMuted (bool mute)   { jassertfalse; return false; }
+ float JUCE_CALLTYPE SystemAudioVolume::getGain()         { jassertfalse; return 0.0f; }
+ bool  JUCE_CALLTYPE SystemAudioVolume::setGain (float)   { jassertfalse; return false; }
+ bool  JUCE_CALLTYPE SystemAudioVolume::isMuted()         { jassertfalse; return false; }
+ bool  JUCE_CALLTYPE SystemAudioVolume::setMuted (bool)   { jassertfalse; return false; }
 #endif
 }