diff --git a/engine/bind/lua b/engine/bind/lua
index e09d90b..446b6d6 100644
Binary files a/engine/bind/lua and b/engine/bind/lua differ
diff --git a/engine/bind/v4k.lua b/engine/bind/v4k.lua
index 37b2f6d..f3b6a85 100644
--- a/engine/bind/v4k.lua
+++ b/engine/bind/v4k.lua
@@ -1876,7 +1876,7 @@ struct bt_t* children;
  void    bt_addfun(const char *name, int(*func)());
  bt_func bt_findfun(const char *name);
  char   *bt_funcname(bt_func fn);
- void ui_bt(bt_t *b);
+ int ui_bt(bt_t *b);
  void    midi_send(unsigned midi_msg);
 typedef struct audio_handle* audio_t;
  audio_t audio_clip( const char *pathfile );
@@ -1889,6 +1889,7 @@ typedef struct audio_handle* audio_t;
  float   audio_volume_clip(float gain);
  float   audio_volume_stream(float gain);
  float   audio_volume_master(float gain);
+ int ui_audio();
 enum AUDIO_FLAGS {
 AUDIO_1CH = 0,
 AUDIO_2CH = 1,
diff --git a/engine/joint/v4k.h b/engine/joint/v4k.h
index b43e05f..7ce8597 100644
--- a/engine/joint/v4k.h
+++ b/engine/joint/v4k.h
@@ -15368,7 +15368,7 @@ API void    bt_addfun(const char *name, int(*func)());
 API bt_func bt_findfun(const char *name);
 API char   *bt_funcname(bt_func fn);
 
-API void ui_bt(bt_t *b);
+API int ui_bt(bt_t *b);
 #line 0
 
 #line 1 "v4k_audio.h"
@@ -15402,6 +15402,8 @@ API float   audio_volume_clip(float gain);   // set     fx volume if gain is in
 API float   audio_volume_stream(float gain); // set    bgm volume if gain is in [0..1] range. return current    bgm volume in any case
 API float   audio_volume_master(float gain); // set master volume if gain is in [0..1] range. return current master volume in any case
 
+API int ui_audio();
+
 enum AUDIO_FLAGS {
     AUDIO_1CH = 0, // default
     AUDIO_2CH = 1,
@@ -581506,7 +581508,7 @@ int audio_init( int flags ) {
         ma_backend_oss,
         ma_backend_jack,
         ma_backend_opensl,
-        //ma_backend_webaudio,
+        ma_backend_webaudio,
         //ma_backend_openal,
         //ma_backend_sdl,
         ma_backend_null    // Lowest priority.
@@ -581771,6 +581773,40 @@ int audio_queue( const void *samples, int num_samples, int flags ) {
 
     return audio_queue_voice;
 }
+
+int ui_audio() {
+    int changed = 0;
+
+    float sfx = sqrt(volume_clip), bgm = sqrt(volume_stream), master = sqrt(volume_master);
+    if( ui_slider2("BGM volume", &bgm, va("%.2f", bgm))) changed = 1, audio_volume_stream(bgm);
+    if( ui_slider2("SFX volume", &sfx, va("%.2f", sfx))) changed = 1, audio_volume_clip(sfx);
+    if( ui_slider2("Master volume", &master, va("%.2f", master))) changed = 1, audio_volume_master(master);
+
+    ui_separator();
+
+    int num_voices = sts_mixer_get_active_voices(&mixer);
+    ui_label2("Format", mixer.audio_format == 0 ? "None" : mixer.audio_format == 1 ? "8-bit" : mixer.audio_format == 2 ? "16-bit" : mixer.audio_format == 3 ? "32-bit integer" : "32-bit float");
+    ui_label2("Frequency", va("%4.1f KHz", mixer.frequency / 1000.0));
+    ui_label2("Voices", va("%d/%d", num_voices, STS_MIXER_VOICES));
+    ui_separator();
+
+    for( int i = 0; i < STS_MIXER_VOICES; ++i ) {
+        if( mixer.voices[i].state != STS_MIXER_VOICE_STOPPED ) { // PLAYING || STREAMING
+            ui_label(va("Voice %d", i+1));
+
+            // float mul = mixer.voices[i].state == STS_MIXER_VOICE_STREAMING ? 2 : 1;
+            // float div = mixer.voices[i].state == STS_MIXER_VOICE_STREAMING ? mixer.voices[i].stream->sample.length : mixer.voices[i].sample->length;
+            // float pct = mixer.voices[i].position * mul / div;
+            // if(ui_slider2("Position", &pct, va("%5.2f", pct))) changed = 1;
+            if(ui_slider2("Gain", &mixer.voices[i].gain, va("%5.2f", mixer.voices[i].gain))) changed = 1;
+            if(ui_slider2("Pitch", &mixer.voices[i].pitch, va("%5.2f", mixer.voices[i].pitch))) changed = 1;
+            if(ui_slider2("Pan", &mixer.voices[i].pan, va("%5.2f", mixer.voices[i].pan))) changed = 1;
+            ui_separator();
+        }
+    }
+
+    return changed;
+}
 #line 0
 
 #line 1 "v4k_collide.c"
@@ -590692,7 +590728,7 @@ GLuint shader_compile( GLenum type, const char *source ) {
 
         // dump log with line numbers
         shader_print( source );
-        PANIC("ERROR: shader_compile(): %s\n%s\n", type == GL_VERTEX_SHADER ? "Vertex" : "Fragment", buf);
+        PRINTF("!ERROR: shader_compile(): %s\n%s\n", type == GL_VERTEX_SHADER ? "Vertex" : "Fragment", buf);
         return 0;
     }
 
@@ -601356,7 +601392,7 @@ int window_frame_begin() {
                 // @todo
             }
             for( int p = (open = ui_collapse_filtered(ICON_MD_VOLUME_UP " Audio", "Debug.Audio")), dummy = (clicked_or_toggled = ui_collapse_clicked()); p; ui_collapse_end(), p = 0) {
-                // @todo
+                ui_audio();
             }
             for( int p = (open = ui_collapse_filtered(ICON_MD_VIDEOCAM " Camera", "Debug.Camera")), dummy = (clicked_or_toggled = ui_collapse_clicked()); p; ui_collapse_end(), p = 0) {
                 ui_camera( camera_get_active() );
@@ -603071,7 +603107,7 @@ int bt_run(bt_t *b) {
     return 0;
 }
 
-void ui_bt(bt_t *b) {
+int ui_bt(bt_t *b) {
     if( b ) {
         char *info = bt_funcname(b->action);
         if(!info) info = va("%d", array_count(b->children));
@@ -603083,6 +603119,7 @@ void ui_bt(bt_t *b) {
             ui_collapse_end();
         }
     }
+    return 0;
 }
 #line 0
 
diff --git a/engine/split/v4k_audio.c b/engine/split/v4k_audio.c
index c64f76e..2f5872a 100644
--- a/engine/split/v4k_audio.c
+++ b/engine/split/v4k_audio.c
@@ -281,7 +281,7 @@ int audio_init( int flags ) {
         ma_backend_oss,
         ma_backend_jack,
         ma_backend_opensl,
-        //ma_backend_webaudio,
+        ma_backend_webaudio,
         //ma_backend_openal,
         //ma_backend_sdl,
         ma_backend_null    // Lowest priority.
@@ -546,3 +546,37 @@ int audio_queue( const void *samples, int num_samples, int flags ) {
 
     return audio_queue_voice;
 }
+
+int ui_audio() {
+    int changed = 0;
+
+    float sfx = sqrt(volume_clip), bgm = sqrt(volume_stream), master = sqrt(volume_master);
+    if( ui_slider2("BGM volume", &bgm, va("%.2f", bgm))) changed = 1, audio_volume_stream(bgm);
+    if( ui_slider2("SFX volume", &sfx, va("%.2f", sfx))) changed = 1, audio_volume_clip(sfx);
+    if( ui_slider2("Master volume", &master, va("%.2f", master))) changed = 1, audio_volume_master(master);
+
+    ui_separator();
+
+    int num_voices = sts_mixer_get_active_voices(&mixer);
+    ui_label2("Format", mixer.audio_format == 0 ? "None" : mixer.audio_format == 1 ? "8-bit" : mixer.audio_format == 2 ? "16-bit" : mixer.audio_format == 3 ? "32-bit integer" : "32-bit float");
+    ui_label2("Frequency", va("%4.1f KHz", mixer.frequency / 1000.0));
+    ui_label2("Voices", va("%d/%d", num_voices, STS_MIXER_VOICES));
+    ui_separator();
+
+    for( int i = 0; i < STS_MIXER_VOICES; ++i ) {
+        if( mixer.voices[i].state != STS_MIXER_VOICE_STOPPED ) { // PLAYING || STREAMING
+            ui_label(va("Voice %d", i+1));
+
+            // float mul = mixer.voices[i].state == STS_MIXER_VOICE_STREAMING ? 2 : 1;
+            // float div = mixer.voices[i].state == STS_MIXER_VOICE_STREAMING ? mixer.voices[i].stream->sample.length : mixer.voices[i].sample->length;
+            // float pct = mixer.voices[i].position * mul / div;
+            // if(ui_slider2("Position", &pct, va("%5.2f", pct))) changed = 1;
+            if(ui_slider2("Gain", &mixer.voices[i].gain, va("%5.2f", mixer.voices[i].gain))) changed = 1;
+            if(ui_slider2("Pitch", &mixer.voices[i].pitch, va("%5.2f", mixer.voices[i].pitch))) changed = 1;
+            if(ui_slider2("Pan", &mixer.voices[i].pan, va("%5.2f", mixer.voices[i].pan))) changed = 1;
+            ui_separator();
+        }
+    }
+
+    return changed;
+}
diff --git a/engine/split/v4k_audio.h b/engine/split/v4k_audio.h
index 3f8c9d0..beb0d3f 100644
--- a/engine/split/v4k_audio.h
+++ b/engine/split/v4k_audio.h
@@ -28,6 +28,8 @@ API float   audio_volume_clip(float gain);   // set     fx volume if gain is in
 API float   audio_volume_stream(float gain); // set    bgm volume if gain is in [0..1] range. return current    bgm volume in any case
 API float   audio_volume_master(float gain); // set master volume if gain is in [0..1] range. return current master volume in any case
 
+API int ui_audio();
+
 enum AUDIO_FLAGS {
     AUDIO_1CH = 0, // default
     AUDIO_2CH = 1,
diff --git a/engine/split/v4k_bt.c b/engine/split/v4k_bt.c
index f88e950..8930632 100644
--- a/engine/split/v4k_bt.c
+++ b/engine/split/v4k_bt.c
@@ -74,7 +74,7 @@ int bt_run(bt_t *b) {
     return 0;
 }
 
-void ui_bt(bt_t *b) {
+int ui_bt(bt_t *b) {
     if( b ) {
         char *info = bt_funcname(b->action);
         if(!info) info = va("%d", array_count(b->children));
@@ -86,4 +86,5 @@ void ui_bt(bt_t *b) {
             ui_collapse_end();
         }
     }
+    return 0;
 }
diff --git a/engine/split/v4k_bt.h b/engine/split/v4k_bt.h
index ba41a82..2a1a75f 100644
--- a/engine/split/v4k_bt.h
+++ b/engine/split/v4k_bt.h
@@ -187,4 +187,4 @@ API void    bt_addfun(const char *name, int(*func)());
 API bt_func bt_findfun(const char *name);
 API char   *bt_funcname(bt_func fn);
 
-API void ui_bt(bt_t *b);
+API int ui_bt(bt_t *b);
diff --git a/engine/split/v4k_render.c b/engine/split/v4k_render.c
index ecea305..dd5b7ca 100644
--- a/engine/split/v4k_render.c
+++ b/engine/split/v4k_render.c
@@ -81,7 +81,7 @@ GLuint shader_compile( GLenum type, const char *source ) {
 
         // dump log with line numbers
         shader_print( source );
-        PANIC("ERROR: shader_compile(): %s\n%s\n", type == GL_VERTEX_SHADER ? "Vertex" : "Fragment", buf);
+        PRINTF("!ERROR: shader_compile(): %s\n%s\n", type == GL_VERTEX_SHADER ? "Vertex" : "Fragment", buf);
         return 0;
     }
 
diff --git a/engine/split/v4k_window.c b/engine/split/v4k_window.c
index 8353093..5ec0f58 100644
--- a/engine/split/v4k_window.c
+++ b/engine/split/v4k_window.c
@@ -564,7 +564,7 @@ int window_frame_begin() {
                 // @todo
             }
             for( int p = (open = ui_collapse_filtered(ICON_MD_VOLUME_UP " Audio", "Debug.Audio")), dummy = (clicked_or_toggled = ui_collapse_clicked()); p; ui_collapse_end(), p = 0) {
-                // @todo
+                ui_audio();
             }
             for( int p = (open = ui_collapse_filtered(ICON_MD_VIDEOCAM " Camera", "Debug.Camera")), dummy = (clicked_or_toggled = ui_collapse_clicked()); p; ui_collapse_end(), p = 0) {
                 ui_camera( camera_get_active() );
diff --git a/engine/v4k.c b/engine/v4k.c
index 5d2f205..137b430 100644
--- a/engine/v4k.c
+++ b/engine/v4k.c
@@ -1247,7 +1247,7 @@ int audio_init( int flags ) {
         ma_backend_oss,
         ma_backend_jack,
         ma_backend_opensl,
-        //ma_backend_webaudio,
+        ma_backend_webaudio,
         //ma_backend_openal,
         //ma_backend_sdl,
         ma_backend_null    // Lowest priority.
@@ -1512,6 +1512,40 @@ int audio_queue( const void *samples, int num_samples, int flags ) {
 
     return audio_queue_voice;
 }
+
+int ui_audio() {
+    int changed = 0;
+
+    float sfx = sqrt(volume_clip), bgm = sqrt(volume_stream), master = sqrt(volume_master);
+    if( ui_slider2("BGM volume", &bgm, va("%.2f", bgm))) changed = 1, audio_volume_stream(bgm);
+    if( ui_slider2("SFX volume", &sfx, va("%.2f", sfx))) changed = 1, audio_volume_clip(sfx);
+    if( ui_slider2("Master volume", &master, va("%.2f", master))) changed = 1, audio_volume_master(master);
+
+    ui_separator();
+
+    int num_voices = sts_mixer_get_active_voices(&mixer);
+    ui_label2("Format", mixer.audio_format == 0 ? "None" : mixer.audio_format == 1 ? "8-bit" : mixer.audio_format == 2 ? "16-bit" : mixer.audio_format == 3 ? "32-bit integer" : "32-bit float");
+    ui_label2("Frequency", va("%4.1f KHz", mixer.frequency / 1000.0));
+    ui_label2("Voices", va("%d/%d", num_voices, STS_MIXER_VOICES));
+    ui_separator();
+
+    for( int i = 0; i < STS_MIXER_VOICES; ++i ) {
+        if( mixer.voices[i].state != STS_MIXER_VOICE_STOPPED ) { // PLAYING || STREAMING
+            ui_label(va("Voice %d", i+1));
+
+            // float mul = mixer.voices[i].state == STS_MIXER_VOICE_STREAMING ? 2 : 1;
+            // float div = mixer.voices[i].state == STS_MIXER_VOICE_STREAMING ? mixer.voices[i].stream->sample.length : mixer.voices[i].sample->length;
+            // float pct = mixer.voices[i].position * mul / div;
+            // if(ui_slider2("Position", &pct, va("%5.2f", pct))) changed = 1;
+            if(ui_slider2("Gain", &mixer.voices[i].gain, va("%5.2f", mixer.voices[i].gain))) changed = 1;
+            if(ui_slider2("Pitch", &mixer.voices[i].pitch, va("%5.2f", mixer.voices[i].pitch))) changed = 1;
+            if(ui_slider2("Pan", &mixer.voices[i].pan, va("%5.2f", mixer.voices[i].pan))) changed = 1;
+            ui_separator();
+        }
+    }
+
+    return changed;
+}
 #line 0
 
 #line 1 "v4k_collide.c"
@@ -10433,7 +10467,7 @@ GLuint shader_compile( GLenum type, const char *source ) {
 
         // dump log with line numbers
         shader_print( source );
-        PANIC("ERROR: shader_compile(): %s\n%s\n", type == GL_VERTEX_SHADER ? "Vertex" : "Fragment", buf);
+        PRINTF("!ERROR: shader_compile(): %s\n%s\n", type == GL_VERTEX_SHADER ? "Vertex" : "Fragment", buf);
         return 0;
     }
 
@@ -21097,7 +21131,7 @@ int window_frame_begin() {
                 // @todo
             }
             for( int p = (open = ui_collapse_filtered(ICON_MD_VOLUME_UP " Audio", "Debug.Audio")), dummy = (clicked_or_toggled = ui_collapse_clicked()); p; ui_collapse_end(), p = 0) {
-                // @todo
+                ui_audio();
             }
             for( int p = (open = ui_collapse_filtered(ICON_MD_VIDEOCAM " Camera", "Debug.Camera")), dummy = (clicked_or_toggled = ui_collapse_clicked()); p; ui_collapse_end(), p = 0) {
                 ui_camera( camera_get_active() );
@@ -22812,7 +22846,7 @@ int bt_run(bt_t *b) {
     return 0;
 }
 
-void ui_bt(bt_t *b) {
+int ui_bt(bt_t *b) {
     if( b ) {
         char *info = bt_funcname(b->action);
         if(!info) info = va("%d", array_count(b->children));
@@ -22824,6 +22858,7 @@ void ui_bt(bt_t *b) {
             ui_collapse_end();
         }
     }
+    return 0;
 }
 #line 0
 
diff --git a/engine/v4k.h b/engine/v4k.h
index feefa2b..a2c696c 100644
--- a/engine/v4k.h
+++ b/engine/v4k.h
@@ -1435,7 +1435,7 @@ API void    bt_addfun(const char *name, int(*func)());
 API bt_func bt_findfun(const char *name);
 API char   *bt_funcname(bt_func fn);
 
-API void ui_bt(bt_t *b);
+API int ui_bt(bt_t *b);
 #line 0
 
 #line 1 "v4k_audio.h"
@@ -1469,6 +1469,8 @@ API float   audio_volume_clip(float gain);   // set     fx volume if gain is in
 API float   audio_volume_stream(float gain); // set    bgm volume if gain is in [0..1] range. return current    bgm volume in any case
 API float   audio_volume_master(float gain); // set master volume if gain is in [0..1] range. return current master volume in any case
 
+API int ui_audio();
+
 enum AUDIO_FLAGS {
     AUDIO_1CH = 0, // default
     AUDIO_2CH = 1,