diff --git a/README.md b/README.md
index 19171494..ba534625 100644
--- a/README.md
+++ b/README.md
@@ -749,18 +749,20 @@ See [the bspwm module](#user-content-dependencies) for details on `label:dimmed`
   This module is still WIP.
 
   Mute and volume changes should affect the appropriate mixers depending on
-  if the headphones are plugged in or not. Still need to add separate output formats
+  weather the headphones are plugged in or not. Still need to add separate output formats
   to indicate it.
 
   ~~~ ini
   [module/volume]
   type = internal/volume
+  ;master_mixer = Master
 
   ; Use the following command to list available mixer controls:
   ; $ amixer scontrols | sed -nr "s/.*'([[:alnum:]]+)'.*/\1/p"
   speaker_mixer = Speaker
   headphone_mixer = Headphone
 
+  ; NOTE: This is required if headphone_mixer is defined
   ; Use the following command to list available device controls
   ; $ amixer controls | sed -r "/CARD/\!d; s/.*=([0-9]+).*name='([^']+)'.*/printf '%3.0f: %s\n' '\1' '\2'/e" | sort
   headphone_control_numid = 9
diff --git a/examples/config b/examples/config
index bd5adcab..9c6950a9 100644
--- a/examples/config
+++ b/examples/config
@@ -24,7 +24,7 @@ font:0 = sans:size=8;0
 font:1 = font awesome:size=10:weight=heavy;0
 
 modules:left = label
-modules:right = cpu ram clock
+modules:right = volume cpu ram clock
 
 [module/label]
 type = custom/text
@@ -58,4 +58,22 @@ format:underline = #7a6
 format:overline = #7a6
 format:padding = 2
 
+[module/volume]
+type = internal/volume
+;speaker_mixer = Speaker
+;headphone_mixer = Headphone
+;headphone_control_numid = 9
+
+format:volume:background = #933484
+format:volume:underline = #9d6294
+format:volume:overline = #9d6294
+format:volume:padding = 2
+format:muted:background = #933484
+format:muted:underline = #9d6294
+format:muted:overline = #9d6294
+format:muted:padding = 2
+
+label:volume = Volume: %percentage%
+label:muted = Sound is muted
+
 ; vim:ft=dosini
diff --git a/include/interfaces/alsa.hpp b/include/interfaces/alsa.hpp
index 5a678d0e..057138a0 100644
--- a/include/interfaces/alsa.hpp
+++ b/include/interfaces/alsa.hpp
@@ -7,11 +7,15 @@
 #include <mutex>
 
 #include "exception.hpp"
+#include "utils/concurrency.hpp"
+#include "utils/macros.hpp"
 
-#define STRSNDERR(s) std::string(snd_strerror(s))
+#define StrSndErr(s) ToStr(snd_strerror(s))
 
 namespace alsa
 {
+  // Errors {{{
+
   class Exception : public ::Exception
   {
     public:
@@ -25,9 +29,16 @@ namespace alsa
         : Exception(msg +" ["+ std::to_string(code) +"]") {}
   };
 
+  class MixerError : public Exception {
+    using Exception::Exception;
+  };
+
+  // }}}
+  // ControlInterface {{{
+
   class ControlInterface
   {
-    std::mutex mtx;
+    concurrency::SpinLock lock;
 
     snd_hctl_t *hctl;
     snd_hctl_elem_t *elem;
@@ -40,20 +51,21 @@ namespace alsa
     public:
       explicit ControlInterface(int numid);
       ~ControlInterface();
+      ControlInterface(const ControlInterface &) = delete;
+      ControlInterface &operator=(const ControlInterface &) = delete;
 
       bool wait(int timeout = -1);
+      void process_events();
 
       bool test_device_plugged();
   };
 
-
-  class MixerError : public Exception {
-    using Exception::Exception;
-  };
+  // }}}
+  // Mixer {{{
 
   class Mixer
   {
-    std::mutex mtx;
+    concurrency::SpinLock lock;
 
     snd_mixer_t *hardware_mixer = nullptr;
     snd_mixer_elem_t *mixer_element = nullptr;
@@ -61,8 +73,11 @@ namespace alsa
     public:
       explicit Mixer(const std::string& mixer_control_name);
       ~Mixer();
+      Mixer(const Mixer &) = delete;
+      Mixer &operator=(const Mixer &) = delete;
 
       bool wait(int timeout = -1);
+      int process_events();
 
       int get_volume();
       void set_volume(float percentage);
@@ -73,4 +88,6 @@ namespace alsa
     protected:
       void error_handler(const std::string& message);
   };
+
+  // }}}
 }
diff --git a/include/modules/volume.hpp b/include/modules/volume.hpp
index 6c85a5cc..b089e405 100644
--- a/include/modules/volume.hpp
+++ b/include/modules/volume.hpp
@@ -19,18 +19,11 @@ namespace modules
     static constexpr auto TAG_LABEL_VOLUME = "<label:volume>";
     static constexpr auto TAG_LABEL_MUTED = "<label:muted>";
 
+    static constexpr auto EVENT_PREFIX = "vol";
     static constexpr auto EVENT_VOLUME_UP = "volup";
     static constexpr auto EVENT_VOLUME_DOWN = "voldown";
     static constexpr auto EVENT_TOGGLE_MUTE = "volmute";
 
-    std::unique_ptr<alsa::Mixer> master_mixer;
-    std::unique_ptr<alsa::Mixer> speaker_mixer;
-    std::unique_ptr<alsa::Mixer> headphone_mixer;
-    std::unique_ptr<alsa::ControlInterface> headphone_ctrl;
-    int headphone_ctrl_numid;
-
-    std::unique_ptr<Builder> builder;
-
     std::unique_ptr<drawtypes::Bar> bar_volume;
     std::unique_ptr<drawtypes::Ramp> ramp_volume;
     std::unique_ptr<drawtypes::Label> label_volume;
@@ -38,8 +31,16 @@ namespace modules
     std::unique_ptr<drawtypes::Label> label_muted;
     std::unique_ptr<drawtypes::Label> label_muted_tokenized;
 
-    int volume = 0;
-    bool muted = false;
+    std::unique_ptr<alsa::Mixer> master_mixer;
+    std::unique_ptr<alsa::Mixer> speaker_mixer;
+    std::unique_ptr<alsa::Mixer> headphone_mixer;
+    std::unique_ptr<alsa::ControlInterface> headphone_ctrl;
+
+    int headphone_ctrl_numid;
+
+    concurrency::Atomic<int> volume;
+    concurrency::Atomic<bool> muted;
+    concurrency::Atomic<bool> has_changed;
 
     public:
       explicit VolumeModule(const std::string& name);
diff --git a/include/utils/concurrency.hpp b/include/utils/concurrency.hpp
index 8f0970cc..9cef07b1 100644
--- a/include/utils/concurrency.hpp
+++ b/include/utils/concurrency.hpp
@@ -56,7 +56,6 @@ namespace concurrency
   template<typename T>
   class Atomic
   {
-    concurrency::SpinLock lock;
     std::atomic<T> value;
 
     public:
@@ -67,25 +66,21 @@ namespace concurrency
 
       void operator=(T value)
       {
-        std::lock_guard<concurrency::SpinLock> lck(this->lock);
         this->value = value;
       }
 
       T operator()()
       {
-        std::lock_guard<concurrency::SpinLock> lck(this->lock);
         return this->value;
       }
 
       operator bool()
       {
-        std::lock_guard<concurrency::SpinLock> lck(this->lock);
         return this->value;
       }
 
       bool operator==(T const& b)
       {
-        std::lock_guard<concurrency::SpinLock> lck(this->lock);
         return this->value == b;
       }
   };
diff --git a/src/eventloop.cpp b/src/eventloop.cpp
index 7acf4a0a..acb8dcfa 100644
--- a/src/eventloop.cpp
+++ b/src/eventloop.cpp
@@ -164,7 +164,7 @@ void EventLoop::read_stdin()
   std::string input;
 
   while ((input = io::readline(this->fd_stdin)).empty() == false) {
-    this->logger->debug("Input value: \'"+ input +"\"");
+    this->logger->debug("Input value: \""+ input +"\"");
 
     bool input_processed = false;
 
diff --git a/src/interfaces/alsa.cpp b/src/interfaces/alsa.cpp
index 0e5823d2..8266e8ef 100644
--- a/src/interfaces/alsa.cpp
+++ b/src/interfaces/alsa.cpp
@@ -8,6 +8,8 @@
 
 namespace alsa
 {
+  // ControlInterface {{{
+
   ControlInterface::ControlInterface(int numid)
   {
     int err;
@@ -20,49 +22,48 @@ namespace alsa
     snd_ctl_elem_info_set_id(this->info, this->id);
 
     if ((err = snd_ctl_open(&this->ctl, ALSA_SOUNDCARD, SND_CTL_NONBLOCK | SND_CTL_READONLY)) < 0)
-      throw ControlInterfaceError(err, "Could not open control \""+ ToStr(ALSA_SOUNDCARD) +"\": "+ STRSNDERR(err));
+      throw ControlInterfaceError(err, "Could not open control \""+ ToStr(ALSA_SOUNDCARD) +"\": "+ StrSndErr(err));
 
     if ((err = snd_ctl_elem_info(this->ctl, this->info)) < 0)
-      throw ControlInterfaceError(err, "Could not get control data: "+ STRSNDERR(err));
+      throw ControlInterfaceError(err, "Could not get control data: "+ StrSndErr(err));
 
     snd_ctl_elem_info_get_id(this->info, this->id);
 
     if ((err = snd_hctl_open(&this->hctl, ALSA_SOUNDCARD, 0)) < 0)
-      throw ControlInterfaceError(err, STRSNDERR(err));
+      throw ControlInterfaceError(err, StrSndErr(err));
     if ((err = snd_hctl_load(this->hctl)) < 0)
-      throw ControlInterfaceError(err, STRSNDERR(err));
+      throw ControlInterfaceError(err, StrSndErr(err));
     if ((elem = snd_hctl_find_elem(this->hctl, this->id)) == nullptr)
       throw ControlInterfaceError(err, "Could not find control with id "+ IntToStr(snd_ctl_elem_id_get_numid(this->id)));
 
     if ((err = snd_ctl_subscribe_events(this->ctl, 1)) < 0)
       throw ControlInterfaceError(err, "Could not subscribe to events: "+ IntToStr(snd_ctl_elem_id_get_numid(this->id)));
 
-    log_trace("Successfully initialized control interface");
+    log_trace("Successfully initialized control interface with ID: "+ IntToStr(numid));
   }
 
-  ControlInterface::~ControlInterface() {
-    std::lock_guard<std::mutex> lck(this->mtx);
+  ControlInterface::~ControlInterface()
+  {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     snd_ctl_close(this->ctl);
     snd_hctl_close(this->hctl);
   }
 
   bool ControlInterface::wait(int timeout)
   {
-    std::lock_guard<std::mutex> lck(this->mtx);
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
 
     int err;
 
     if ((err = snd_ctl_wait(this->ctl, timeout)) < 0)
-      throw ControlInterfaceError(err, "Failed to wait for events: "+ STRSNDERR(err));
+      throw ControlInterfaceError(err, "Failed to wait for events: "+ StrSndErr(err));
 
     snd_ctl_event_t *event;
     snd_ctl_event_alloca(&event);
 
-    if ((err = snd_ctl_read(this->ctl, event)) < 0) {
-      log_trace(err);
+    if ((err = snd_ctl_read(this->ctl, event)) < 0)
       return false;
-    }
-
     if (snd_ctl_event_get_type(event) != SND_CTL_EVENT_ELEM)
       return false;
 
@@ -73,14 +74,18 @@ namespace alsa
 
   bool ControlInterface::test_device_plugged()
   {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     int err;
 
     if ((err = snd_hctl_elem_read(this->elem, this->value)) < 0)
-      throw ControlInterfaceError(err, "Could not read control value: "+ STRSNDERR(err));
+      throw ControlInterfaceError(err, "Could not read control value: "+ StrSndErr(err));
 
     return snd_ctl_elem_value_get_boolean(this->value, 0);
   }
 
+  // }}}
+  // Mixer {{{
 
   Mixer::Mixer(const std::string& mixer_control_name)
   {
@@ -103,33 +108,46 @@ namespace alsa
     if ((this->mixer_element = snd_mixer_find_selem(this->hardware_mixer, mixer_id)) == nullptr)
       throw MixerError("Cannot find simple element");
 
-    log_trace("Successfully initialized mixer");
+    log_trace("Successfully initialized mixer: "+ mixer_control_name);
   }
 
-  Mixer::~Mixer() {
-    std::lock_guard<std::mutex> lck(this->mtx);
+  Mixer::~Mixer()
+  {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     snd_mixer_elem_remove(this->mixer_element);
     snd_mixer_detach(this->hardware_mixer, ALSA_SOUNDCARD);
     snd_mixer_close(this->hardware_mixer);
   }
 
+  int Mixer::process_events()
+  {
+    int num_events = snd_mixer_handle_events(this->hardware_mixer);
+
+    if (num_events < 0)
+      throw MixerError("Failed to process pending events: "+ StrSndErr(num_events));
+
+    return num_events;
+  }
+
   bool Mixer::wait(int timeout)
   {
-    std::lock_guard<std::mutex> lck(this->mtx);
+    assert(this->hardware_mixer);
 
-    int err, pend_n = 0;
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
 
-    if (this->hardware_mixer != nullptr && (err = snd_mixer_wait(this->hardware_mixer, timeout)) < 0)
-      throw MixerError("Failed to wait for events: "+ STRSNDERR(err));
+    int err = snd_mixer_wait(this->hardware_mixer, timeout);
 
-    if (this->hardware_mixer != nullptr && (pend_n = snd_mixer_handle_events(this->hardware_mixer)) < 0)
-      throw MixerError("Failed to process pending events: "+ STRSNDERR(err));
+    if (err < 0)
+      throw MixerError("Failed to wait for events: "+ StrSndErr(err));
 
-    return pend_n > 0;
+    return this->process_events() > 0;
   }
 
   int Mixer::get_volume()
   {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     long chan_n = 0, vol_total = 0, vol, vol_min, vol_max;
 
     snd_mixer_selem_get_playback_volume_range(this->mixer_element, &vol_min, &vol_max);
@@ -143,7 +161,7 @@ namespace alsa
       }
     }
 
-    return (int) 100 * (vol_total / chan_n) / vol_max + 0.5f;
+    return (int) 100.0f * (vol_total / chan_n) / vol_max + 0.5f;
   }
 
   void Mixer::set_volume(float percentage)
@@ -151,18 +169,25 @@ namespace alsa
     if (this->is_muted())
       return;
 
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     long vol_min, vol_max;
 
     snd_mixer_selem_get_playback_volume_range(this->mixer_element, &vol_min, &vol_max);
     snd_mixer_selem_set_playback_volume_all(this->mixer_element, vol_max * percentage / 100);
   }
 
-  void Mixer::set_mute(bool mode) {
+  void Mixer::set_mute(bool mode)
+  {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     snd_mixer_selem_set_playback_switch_all(this->mixer_element, mode);
   }
 
   void Mixer::toggle_mute()
   {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     int state;
     snd_mixer_selem_get_playback_switch(this->mixer_element, SND_MIXER_SCHN_FRONT_LEFT, &state);
     snd_mixer_selem_set_playback_switch_all(this->mixer_element, !state);
@@ -170,6 +195,8 @@ namespace alsa
 
   bool Mixer::is_muted()
   {
+    std::lock_guard<concurrency::SpinLock> lck(this->lock);
+
     int state = 0;
     repeat(SND_MIXER_SCHN_LAST)
     {
@@ -179,6 +206,9 @@ namespace alsa
           return true;
       }
     }
+
     return false;
   }
+
+  // }}}
 }
diff --git a/src/modules/volume.cpp b/src/modules/volume.cpp
index 8ca9d05f..229922f1 100644
--- a/src/modules/volume.cpp
+++ b/src/modules/volume.cpp
@@ -8,6 +8,8 @@ using namespace modules;
 
 VolumeModule::VolumeModule(const std::string& name_) : EventModule(name_)
 {
+  // Load configuration values {{{
+  auto master_mixer = config::get<std::string>(name(), "master_mixer", "Master");
   auto speaker_mixer = config::get<std::string>(name(), "speaker_mixer", "");
   auto headphone_mixer = config::get<std::string>(name(), "headphone_mixer", "");
 
@@ -15,14 +17,16 @@ VolumeModule::VolumeModule(const std::string& name_) : EventModule(name_)
 
   if (!headphone_mixer.empty() && this->headphone_ctrl_numid == -1)
     throw ModuleError("[VolumeModule] Missing required property value for \"headphone_control_numid\"...");
-  else if (headphone_mixer.empty())
+  else if (headphone_mixer.empty() && this->headphone_ctrl_numid != -1)
     throw ModuleError("[VolumeModule] Missing required property value for \"headphone_mixer\"...");
 
   if (string::lower(speaker_mixer) == "master")
     throw ModuleError("[VolumeModule] The \"Master\" mixer is already processed internally. Specify another mixer or comment out the \"speaker_mixer\" parameter...");
   if (string::lower(headphone_mixer) == "master")
     throw ModuleError("[VolumeModule] The \"Master\" mixer is already processed internally. Specify another mixer or comment out the \"headphone_mixer\" parameter...");
+  // }}}
 
+  // Setup mixers {{{
   auto create_mixer = [](std::string mixer_name)
   {
     std::unique_ptr<alsa::Mixer> mixer;
@@ -37,7 +41,7 @@ VolumeModule::VolumeModule(const std::string& name_) : EventModule(name_)
     return mixer;
   };
 
-  this->master_mixer = create_mixer("Master");
+  this->master_mixer = create_mixer(master_mixer);
 
   if (!speaker_mixer.empty())
     this->speaker_mixer = create_mixer(speaker_mixer);
@@ -57,9 +61,9 @@ VolumeModule::VolumeModule(const std::string& name_) : EventModule(name_)
       this->headphone_ctrl.reset();
     }
   }
+  // }}}
 
-  this->builder = std::make_unique<Builder>();
-
+  // Add formats and elements {{{
   this->formatter->add(FORMAT_VOLUME, TAG_LABEL_VOLUME,
     { TAG_RAMP_VOLUME, TAG_LABEL_VOLUME, TAG_BAR_VOLUME });
   this->formatter->add(FORMAT_MUTED, TAG_LABEL_MUTED,
@@ -77,14 +81,16 @@ VolumeModule::VolumeModule(const std::string& name_) : EventModule(name_)
     this->label_muted = drawtypes::get_optional_config_label(name(), get_tag_name(TAG_LABEL_MUTED), "%percentage%");
     this->label_muted_tokenized = this->label_muted->clone();
   }
+  // }}}
 
+  // Sign up for stdin events {{{
   register_command_handler(name());
+  // }}}
 }
 
 VolumeModule::~VolumeModule()
 {
   std::lock_guard<concurrency::SpinLock> lck(this->update_lock);
-
   this->master_mixer.reset();
   this->speaker_mixer.reset();
   this->headphone_mixer.reset();
@@ -95,14 +101,17 @@ bool VolumeModule::has_event()
 {
   bool has_event = false;
 
+  if (this->has_changed())
+    has_event = true;
+
   try {
-    if (this->master_mixer)
+    if (!has_event && this->master_mixer)
       has_event |= this->master_mixer->wait(25);
-    if (this->speaker_mixer)
+    if (!has_event && this->speaker_mixer)
       has_event |= this->speaker_mixer->wait(25);
-    if (this->headphone_mixer)
+    if (!has_event && this->headphone_mixer)
       has_event |= this->headphone_mixer->wait(25);
-    if (this->headphone_ctrl)
+    if (!has_event && this->headphone_ctrl)
       has_event |= this->headphone_ctrl->wait(25);
   } catch (alsa::Exception &e) {
     log_error(e.what());
@@ -113,21 +122,26 @@ bool VolumeModule::has_event()
 
 bool VolumeModule::update()
 {
-  int volume = 0;
+  // Consume any other pending events
+  this->has_changed = false;
+  if (this->master_mixer)
+    this->master_mixer->process_events();
+  if (this->speaker_mixer)
+    this->speaker_mixer->process_events();
+  if (this->headphone_mixer)
+    this->headphone_mixer->process_events();
+  if (this->headphone_ctrl)
+    this->headphone_ctrl->wait(0);
+
+  int volume = 100;
   bool muted = false;
-  auto headphones_connected = false;
 
   if (this->master_mixer) {
-    volume = this->master_mixer->get_volume();
+    volume *= this->master_mixer->get_volume() / 100.0f;
     muted |= this->master_mixer->is_muted();
-  } else {
-    volume = 100;
   }
 
-  if (this->headphone_ctrl && this->headphone_mixer)
-    headphones_connected = this->headphone_ctrl->test_device_plugged();
-
-  if (headphones_connected) {
+  if (this->headphone_mixer && this->headphone_ctrl && this->headphone_ctrl->test_device_plugged()) {
     volume *= this->headphone_mixer->get_volume() / 100.0f;
     muted |= this->headphone_mixer->is_muted();
   } else if (this->speaker_mixer) {
@@ -139,26 +153,29 @@ bool VolumeModule::update()
   this->muted = muted;
 
   this->label_volume_tokenized->text = this->label_volume->text;
-  this->label_volume_tokenized->replace_token("%percentage%", std::to_string(this->volume) +"%");
+  this->label_volume_tokenized->replace_token("%percentage%", std::to_string(this->volume()) +"%");
 
   this->label_muted_tokenized->text = this->label_muted->text;
-  this->label_muted_tokenized->replace_token("%percentage%", std::to_string(this->volume) +"%");
+  this->label_muted_tokenized->replace_token("%percentage%", std::to_string(this->volume()) +"%");
 
   return true;
 }
 
-std::string VolumeModule::get_format() {
-  return this->muted ? FORMAT_MUTED : FORMAT_VOLUME;
+std::string VolumeModule::get_format()
+{
+  return this->muted() == true ? FORMAT_MUTED : FORMAT_VOLUME;
 }
 
 std::string VolumeModule::get_output()
 {
   this->builder->cmd(Cmd::LEFT_CLICK, EVENT_TOGGLE_MUTE);
 
-  if (volume < 100)
-    this->builder->cmd(Cmd::SCROLL_UP, EVENT_VOLUME_UP, volume < 100);
-  if (volume > 0)
-    this->builder->cmd(Cmd::SCROLL_DOWN, EVENT_VOLUME_DOWN);
+  if (!this->muted()) {
+    if (this->volume() < 100)
+      this->builder->cmd(Cmd::SCROLL_UP, EVENT_VOLUME_UP);
+    if (this->volume() > 0)
+      this->builder->cmd(Cmd::SCROLL_DOWN, EVENT_VOLUME_DOWN);
+  }
 
   this->builder->node(this->Module::get_output());
 
@@ -167,8 +184,6 @@ std::string VolumeModule::get_output()
 
 bool VolumeModule::build(Builder *builder, const std::string& tag)
 {
-  bool built = true;
-
   if (tag == TAG_BAR_VOLUME)
     builder->node(this->bar_volume, volume);
   else if (tag == TAG_RAMP_VOLUME)
@@ -178,52 +193,60 @@ bool VolumeModule::build(Builder *builder, const std::string& tag)
   else if (tag == TAG_LABEL_MUTED)
     builder->node(this->label_muted_tokenized);
   else
-    built = false;
+    return false;
 
-  return built;
+  return true;
 }
 
 bool VolumeModule::handle_command(const std::string& cmd)
 {
-  if (cmd.length() < 3 || cmd.substr(0, 3) != "vol")
+  if (cmd.length() < std::strlen(EVENT_PREFIX))
     return false;
+  if (std::strncmp(cmd.c_str(), EVENT_PREFIX, 3) != 0)
+    return false;
+
+  std::lock_guard<concurrency::SpinLock> lck(this->update_lock);
 
   alsa::Mixer *master_mixer = nullptr;
   alsa::Mixer *other_mixer = nullptr;
 
-  bool headphones_connected = false;
+  if (this->master_mixer)
+    master_mixer = this->master_mixer.get();
 
-  if (this->headphone_ctrl && this->headphone_mixer)
-    headphones_connected = this->headphone_ctrl->test_device_plugged();
+  if (master_mixer == nullptr)
+    return false;
 
-  if (headphones_connected)
+  if (this->headphone_mixer && this->headphone_ctrl && this->headphone_ctrl->test_device_plugged())
     other_mixer = this->headphone_mixer.get();
   else if (this->speaker_mixer)
     other_mixer = this->speaker_mixer.get();
 
-  if (this->master_mixer)
-    master_mixer = this->master_mixer.get();
+  // Toggle mute state
+  if (std::strncmp(cmd.c_str(), EVENT_TOGGLE_MUTE, std::strlen(EVENT_TOGGLE_MUTE)) == 0) {
+    master_mixer->set_mute(this->muted());
+
+    if (other_mixer != nullptr)
+      other_mixer->set_mute(this->muted());
+
+  // Increase volume
+  } else if (std::strncmp(cmd.c_str(), EVENT_VOLUME_UP, std::strlen(EVENT_VOLUME_UP)) == 0) {
+    master_mixer->set_volume(math::cap<float>(master_mixer->get_volume() + 5, 0, 100));
+
+    if (other_mixer != nullptr)
+      other_mixer->set_volume(math::cap<float>(other_mixer->get_volume() + 5, 0, 100));
+
+  // Decrease volume
+  } else if (std::strncmp(cmd.c_str(), EVENT_VOLUME_DOWN, std::strlen(EVENT_VOLUME_DOWN)) == 0) {
+    master_mixer->set_volume(math::cap<float>(master_mixer->get_volume() - 5, 0, 100));
+
+    if (other_mixer != nullptr)
+      other_mixer->set_volume(math::cap<float>(other_mixer->get_volume() - 5, 0, 100));
 
-  if (cmd == EVENT_VOLUME_UP) {
-    auto vol = math::cap<float>(this->master_mixer->get_volume() + 5, 0, 100);
-    if (master_mixer != nullptr)
-      master_mixer->set_volume(vol);
-  } else if (cmd == EVENT_VOLUME_DOWN) {
-    auto vol = math::cap<float>(this->master_mixer->get_volume() - 5, 0, 100);
-    if (master_mixer != nullptr)
-      master_mixer->set_volume(vol);
-  } else if (cmd == EVENT_TOGGLE_MUTE) {
-    if (master_mixer != nullptr)
-      master_mixer->toggle_mute();
-    if (other_mixer != nullptr) {
-      if (master_mixer != nullptr)
-        other_mixer->set_mute(!master_mixer->is_muted());
-      else
-        other_mixer->toggle_mute();
-    }
   } else {
     return false;
   }
 
+  this->has_changed = true;
+
   return true;
 }