diff --git a/src/mixer/MixerType.cxx b/src/mixer/MixerType.cxx
index 47016fd0a..0605f0979 100644
--- a/src/mixer/MixerType.cxx
+++ b/src/mixer/MixerType.cxx
@@ -29,11 +29,11 @@ mixer_type_parse(const char *input)
 	assert(input != NULL);
 
 	if (strcmp(input, "none") == 0 || strcmp(input, "disabled") == 0)
-		return MIXER_TYPE_NONE;
+		return MixerType::NONE;
 	else if (strcmp(input, "hardware") == 0)
-		return MIXER_TYPE_HARDWARE;
+		return MixerType::HARDWARE;
 	else if (strcmp(input, "software") == 0)
-		return MIXER_TYPE_SOFTWARE;
+		return MixerType::SOFTWARE;
 	else
-		return MIXER_TYPE_UNKNOWN;
+		return MixerType::UNKNOWN;
 }
diff --git a/src/mixer/MixerType.hxx b/src/mixer/MixerType.hxx
index a5e635e06..9831e3db6 100644
--- a/src/mixer/MixerType.hxx
+++ b/src/mixer/MixerType.hxx
@@ -20,26 +20,26 @@
 #ifndef MPD_MIXER_TYPE_HXX
 #define MPD_MIXER_TYPE_HXX
 
-enum MixerType {
+enum class MixerType {
 	/** parser error */
-	MIXER_TYPE_UNKNOWN,
+	UNKNOWN,
 
 	/** mixer disabled */
-	MIXER_TYPE_NONE,
+	NONE,
 
 	/** software mixer with pcm_volume() */
-	MIXER_TYPE_SOFTWARE,
+	SOFTWARE,
 
 	/** hardware mixer (output's plugin) */
-	MIXER_TYPE_HARDWARE,
+	HARDWARE,
 };
 
 /**
  * Parses a #MixerType setting from the configuration file.
  *
- * @param input the configured string value; must not be NULL
- * @return a #MixerType value; MIXER_TYPE_UNKNOWN means #input could
- * not be parsed
+ * @param input the configured string value; must not be NULL @return
+ * a #MixerType value; #MixerType::UNKNOWN means #input could not be
+ * parsed
  */
 MixerType
 mixer_type_parse(const char *input);
diff --git a/src/output/Init.cxx b/src/output/Init.cxx
index f195f6b8b..3518c5c64 100644
--- a/src/output/Init.cxx
+++ b/src/output/Init.cxx
@@ -103,7 +103,7 @@ audio_output_mixer_type(const config_param &param)
 
 	/* try the local "mixer_enabled" setting next (deprecated) */
 	if (!param.GetBlockValue("mixer_enabled", true))
-		return MIXER_TYPE_NONE;
+		return MixerType::NONE;
 
 	/* fall back to the global "mixer_type" setting (also
 	   deprecated) */
@@ -122,18 +122,18 @@ audio_output_load_mixer(EventLoop &event_loop, AudioOutput &ao,
 	Mixer *mixer;
 
 	switch (audio_output_mixer_type(param)) {
-	case MIXER_TYPE_NONE:
-	case MIXER_TYPE_UNKNOWN:
+	case MixerType::NONE:
+	case MixerType::UNKNOWN:
 		return nullptr;
 
-	case MIXER_TYPE_HARDWARE:
+	case MixerType::HARDWARE:
 		if (plugin == nullptr)
 			return nullptr;
 
 		return mixer_new(event_loop, *plugin, ao, listener,
 				 param, error);
 
-	case MIXER_TYPE_SOFTWARE:
+	case MixerType::SOFTWARE:
 		mixer = mixer_new(event_loop, software_mixer_plugin, ao,
 				  listener,
 				  config_param(),