diff --git a/application/palemoon/app/profile/palemoon.js b/application/palemoon/app/profile/palemoon.js
index 15accd1467..e53b1693b7 100644
--- a/application/palemoon/app/profile/palemoon.js
+++ b/application/palemoon/app/profile/palemoon.js
@@ -463,6 +463,10 @@ pref("browser.tabs.closeButtons", 1);
 // false  return to the adjacent tab (old default)
 pref("browser.tabs.selectOwnerOnClose", true);
 
+pref("browser.tabs.showAudioPlayingIcon", true);
+// This should match Chromium's audio indicator delay.
+pref("browser.tabs.delayHidingAudioPlayingIconMS", 3000);
+
 pref("browser.allTabs.previews", true);
 pref("browser.ctrlTab.previews", true);
 pref("browser.ctrlTab.recentlyUsedLimit", 7);
diff --git a/application/palemoon/base/content/tabbrowser.xml b/application/palemoon/base/content/tabbrowser.xml
index dc6cb0a9d1..0a2a1c3f5f 100644
--- a/application/palemoon/base/content/tabbrowser.xml
+++ b/application/palemoon/base/content/tabbrowser.xml
@@ -3347,6 +3347,78 @@
             tab.setAttribute("titlechanged", "true");
         ]]>
       </handler>
+      <handler event="DOMAudioPlaybackStarted">
+        <![CDATA[
+          var tab = getTabFromAudioEvent(event)
+          if (!tab) {
+            return;
+          }
+
+          clearTimeout(tab._soundPlayingAttrRemovalTimer);
+          tab._soundPlayingAttrRemovalTimer = 0;
+
+          let modifiedAttrs = [];
+          if (tab.hasAttribute("soundplaying-scheduledremoval")) {
+            tab.removeAttribute("soundplaying-scheduledremoval");
+            modifiedAttrs.push("soundplaying-scheduledremoval");
+          }
+
+          if (!tab.hasAttribute("soundplaying")) {
+            tab.setAttribute("soundplaying", true);
+            modifiedAttrs.push("soundplaying");
+          }
+
+          this._tabAttrModified(tab, modifiedAttrs);
+        ]]>
+      </handler>
+      <handler event="DOMAudioPlaybackStopped">
+        <![CDATA[
+          var tab = getTabFromAudioEvent(event)
+          if (!tab) {
+            return;
+          }
+
+          if (tab.hasAttribute("soundplaying")) {
+            let removalDelay = Services.prefs.getIntPref("browser.tabs.delayHidingAudioPlayingIconMS");
+
+            tab.style.setProperty("--soundplaying-removal-delay", `${removalDelay - 300}ms`);
+            tab.setAttribute("soundplaying-scheduledremoval", "true");
+            this._tabAttrModified(tab, ["soundplaying-scheduledremoval"]);
+
+            tab._soundPlayingAttrRemovalTimer = setTimeout(() => {
+              tab.removeAttribute("soundplaying-scheduledremoval");
+              tab.removeAttribute("soundplaying");
+              this._tabAttrModified(tab, ["soundplaying", "soundplaying-scheduledremoval"]);
+            }, removalDelay);
+          }
+        ]]>
+      </handler>
+      <handler event="DOMAudioPlaybackBlockStarted">
+        <![CDATA[
+          var tab = getTabFromAudioEvent(event)
+          if (!tab) {
+            return;
+          }
+
+          if (!tab.hasAttribute("blocked")) {
+            tab.setAttribute("blocked", true);
+            this._tabAttrModified(tab, ["blocked"]);
+          }
+        ]]>
+      </handler>
+      <handler event="DOMAudioPlaybackBlockStopped">
+        <![CDATA[
+          var tab = getTabFromAudioEvent(event)
+          if (!tab) {
+            return;
+          }
+
+          if (tab.hasAttribute("blocked")) {
+            tab.removeAttribute("blocked");
+            this._tabAttrModified(tab, ["blocked"]);
+          }
+        ]]>
+      </handler>
     </handlers>
   </binding>
 
@@ -4762,6 +4834,10 @@
                      xbl:inherits="value=label,crop,accesskey,fadein,pinned,selected"
                      class="tab-text tab-label"
                      role="presentation"/>
+          <xul:image xbl:inherits="soundplaying,soundplaying-scheduledremoval,pinned,muted,blocked,selected=visuallyselected"
+                     anonid="soundplaying-icon"
+                     class="tab-icon-sound"
+                     role="presentation"/>
           <xul:toolbarbutton anonid="close-button"
                              xbl:inherits="fadein,pinned,selected"
                              class="tab-close-button close-icon"/>
@@ -4782,9 +4858,59 @@
       </property>
 
       <field name="mOverCloseButton">false</field>
+      <property name="_overPlayingIcon" readonly="true">
+        <getter><![CDATA[
+          let iconVisible = this.hasAttribute("soundplaying") ||
+                            this.hasAttribute("muted") ||
+                            this.hasAttribute("blocked");
+          let soundPlayingIcon =
+            document.getAnonymousElementByAttribute(this, "anonid", "soundplaying-icon");
+          let overlayIcon =
+            document.getAnonymousElementByAttribute(this, "anonid", "overlay-icon");
+
+          return soundPlayingIcon && soundPlayingIcon.matches(":hover") ||
+                 (overlayIcon && overlayIcon.matches(":hover") && iconVisible);
+        ]]></getter>
+      </property>
       <field name="mCorrespondingMenuitem">null</field>
       <field name="closing">false</field>
       <field name="lastAccessed">0</field>
+      
+      <method name="toggleMuteAudio">
+        <parameter name="aMuteReason"/>
+        <body>
+        <![CDATA[
+          let tabContainer = this.parentNode;
+          let browser = this.linkedBrowser;
+          let modifiedAttrs = [];
+          if (browser.audioBlocked) {
+            this.removeAttribute("blocked");
+            modifiedAttrs.push("blocked");
+
+            // We don't want sound icon flickering between "blocked", "none" and
+            // "sound-playing", here adding the "soundplaying" is to keep the
+            // transition smoothly.
+            if (!this.hasAttribute("soundplaying")) {
+              this.setAttribute("soundplaying", true);
+              modifiedAttrs.push("soundplaying");
+            }
+
+            browser.resumeMedia();
+          } else {
+            if (browser.audioMuted) {
+              browser.unmute();
+              this.removeAttribute("muted");
+            } else {
+              browser.mute();
+              this.setAttribute("muted", "true");
+            }
+            this.muteReason = aMuteReason || null;
+            modifiedAttrs.push("muted");
+          }
+          tabContainer.tabbrowser._tabAttrModified(this, modifiedAttrs);
+        ]]>
+        </body>
+      </method>
     </implementation>
 
     <handlers>
@@ -4843,7 +4969,8 @@
         if (this.selected) {
           this.style.MozUserFocus = 'ignore';
           this.clientTop; // just using this to flush style updates
-        } else if (this.mOverCloseButton) {
+        } else if (this.mOverCloseButton ||
+                   this._overPlayingIcon) {
           // Prevent tabbox.xml from selecting the tab.
           event.stopPropagation();
         }
@@ -4852,6 +4979,17 @@
       <handler event="mouseup">
         this.style.MozUserFocus = '';
       </handler>
+      <handler event="click">
+      <![CDATA[
+        if (event.button != 0) {
+          return;
+        }
+
+        if (this._overPlayingIcon) {
+          this.toggleMuteAudio();
+        }
+      ]]>
+      </handler>
     </handlers>
   </binding>
 
diff --git a/application/palemoon/themes/linux/browser.css b/application/palemoon/themes/linux/browser.css
index c6587babcc..cf48dc8196 100644
--- a/application/palemoon/themes/linux/browser.css
+++ b/application/palemoon/themes/linux/browser.css
@@ -1758,6 +1758,79 @@ richlistitem[type~="action"][actiontype="switchtab"] > .ac-url-box > .ac-action-
   -moz-margin-end: -1px;
 }
 
+/* Tab sound indicator */
+.tab-icon-sound {
+  -moz-margin-start: 4px;
+  width: 16px;
+  height: 16px;
+  padding: 0;
+}
+
+.tab-icon-sound:not(:-moz-any([soundplaying],[muted])),
+.tab-icon-sound[pinned] {
+  display: none;
+}
+
+.tab-icon-sound[soundplaying] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio");
+}
+
+.tab-icon-sound[soundplaying]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-hover");
+}
+
+.tab-icon-sound[soundplaying]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-pressed");
+}
+
+.tab-icon-sound[muted],
+.tab-icon-sound[blocked] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted");
+}
+
+.tab-icon-sound[muted]:hover,
+.tab-icon-sound[blocked]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-hover");
+}
+
+.tab-icon-sound[muted]:hover:active,
+.tab-icon-sound[blocked]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-pressed");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark-hover");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark-pressed");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked],
+#TabsToolbar[brighttext] .tab-icon-sound[muted] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked]:hover,
+#TabsToolbar[brighttext] .tab-icon-sound[muted]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark-hover");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked]:hover:active,
+#TabsToolbar[brighttext] .tab-icon-sound[muted]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark-pressed");
+}
+
+.tab-icon-sound[soundplaying-scheduledremoval]:not([muted]):not(:hover),
+.tab-icon-overlay[soundplaying-scheduledremoval]:not([muted]):not(:hover) {
+  transition: opacity .3s linear var(--soundplaying-removal-delay);
+  opacity: 0;
+}
+
 /* Tabstrip new tab button */
 .tabs-newtab-button,
 #TabsToolbar > #new-tab-button ,
diff --git a/application/palemoon/themes/linux/jar.mn b/application/palemoon/themes/linux/jar.mn
index 8b2e9dc77e..8cb6878e8b 100644
--- a/application/palemoon/themes/linux/jar.mn
+++ b/application/palemoon/themes/linux/jar.mn
@@ -123,6 +123,8 @@ browser.jar:
   skin/classic/browser/tabbrowser/tab.png             (tabbrowser/tab.png)
   skin/classic/browser/tabbrowser/tab-overflow-border.png (tabbrowser/tab-overflow-border.png)
   skin/classic/browser/tabbrowser/tabDragIndicator.png (tabbrowser/tabDragIndicator.png)
+  skin/classic/browser/tabbrowser/tab-audio.svg       (../shared/tabbrowser/tab-audio.svg)
+  skin/classic/browser/tabbrowser/tab-audio-small.svg (../shared/tabbrowser/tab-audio-small.svg)
 #ifdef MOZ_SERVICES_SYNC
   skin/classic/browser/sync-16-throbber.png
   skin/classic/browser/sync-16.png
diff --git a/application/palemoon/themes/osx/browser.css b/application/palemoon/themes/osx/browser.css
index a915af3a3c..d9b7d12715 100644
--- a/application/palemoon/themes/osx/browser.css
+++ b/application/palemoon/themes/osx/browser.css
@@ -1821,6 +1821,79 @@ richlistitem[type~="action"][actiontype="switchtab"][selected="true"] > .ac-url-
     }
 }
   
+/* Tab sound indicator */
+.tab-icon-sound {
+  -moz-margin-start: 4px;
+  width: 16px;
+  height: 16px;
+  padding: 0;
+}
+
+.tab-icon-sound:not(:-moz-any([soundplaying],[muted])),
+.tab-icon-sound[pinned] {
+  display: none;
+}
+
+.tab-icon-sound[soundplaying] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio");
+}
+
+.tab-icon-sound[soundplaying]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-hover");
+}
+
+.tab-icon-sound[soundplaying]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-pressed");
+}
+
+.tab-icon-sound[muted],
+.tab-icon-sound[blocked] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted");
+}
+
+.tab-icon-sound[muted]:hover,
+.tab-icon-sound[blocked]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-hover");
+}
+
+.tab-icon-sound[muted]:hover:active,
+.tab-icon-sound[blocked]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-pressed");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark-hover");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark-pressed");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked],
+#TabsToolbar[brighttext] .tab-icon-sound[muted] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked]:hover,
+#TabsToolbar[brighttext] .tab-icon-sound[muted]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark-hover");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked]:hover:active,
+#TabsToolbar[brighttext] .tab-icon-sound[muted]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark-pressed");
+}
+
+.tab-icon-sound[soundplaying-scheduledremoval]:not([muted]):not(:hover),
+.tab-icon-overlay[soundplaying-scheduledremoval]:not([muted]):not(:hover) {
+  transition: opacity .3s linear var(--soundplaying-removal-delay);
+  opacity: 0;
+}
+
 /* Tab scrollbox arrow, tabstrip new tab and all-tabs buttons */
 
 .tabbrowser-arrowscrollbox > .scrollbutton-up,
diff --git a/application/palemoon/themes/osx/jar.mn b/application/palemoon/themes/osx/jar.mn
index a665639894..1a11d0a30d 100644
--- a/application/palemoon/themes/osx/jar.mn
+++ b/application/palemoon/themes/osx/jar.mn
@@ -166,6 +166,8 @@ browser.jar:
         skin/classic/browser/tabbrowser/tab-arrow-left-inverted.png  (tabbrowser/tab-arrow-left-inverted.png)
         skin/classic/browser/tabbrowser/tab-overflow-border.png      (tabbrowser/tab-overflow-border.png)
         skin/classic/browser/tabbrowser/tabDragIndicator.png         (tabbrowser/tabDragIndicator.png)
+        skin/classic/browser/tabbrowser/tab-audio.svg                (../shared/tabbrowser/tab-audio.svg)
+        skin/classic/browser/tabbrowser/tab-audio-small.svg          (../shared/tabbrowser/tab-audio-small.svg)
 #ifdef MOZ_SERVICES_SYNC
         skin/classic/browser/sync-throbber.png
         skin/classic/browser/sync-16.png
diff --git a/application/palemoon/themes/shared/tabbrowser/tab-audio-small.svg b/application/palemoon/themes/shared/tabbrowser/tab-audio-small.svg
new file mode 100644
index 0000000000..da4ad3ef9b
--- /dev/null
+++ b/application/palemoon/themes/shared/tabbrowser/tab-audio-small.svg
@@ -0,0 +1,85 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="16" height="16" viewBox="0 0 16 16">
+  <style>
+    use:not(:target) {
+      display: none;
+    }
+    .icon {
+      fill: #4d4d4d;
+    }
+    .icon.hover {
+      fill: #333333;
+    }
+    .icon.pressed {
+      fill: #000;
+    }
+    .icon.dark {
+      fill: #ccc;
+    }
+    .icon.dark.hover {
+      fill: #b2b2b2;
+    }
+    .icon.dark.pressed {
+      fill: #fff;
+    }
+    .muted {
+      opacity: .7;
+      stroke: #4d4d4d;
+      stroke-width: 0;
+    }
+    .muted.hover {
+      opacity: .85;
+      stroke: #333333;
+    }
+    .muted.pressed {
+      opacity: 1;
+      stroke: #000;
+    }
+    .muted.dark {
+      stroke: #ccc;
+    }
+    .muted.dark.hover {
+      stroke: #b2b2b2;
+    }
+    .muted.dark.pressed {
+      stroke: #fff;
+    }
+  </style>
+  <defs>
+    <clipPath id="clip-wave">
+      <path d="M 11,7 l 3,-8 l 2,0 l 0,18 l -2,0 l -3,-8 z" />
+    </clipPath>
+    <mask id="disabled-cutout">
+      <rect width="16" height="16" fill="#fff" />
+      <line x1="4" y1="14" x2="14" y2="4" stroke="#000" stroke-width="2" />
+    </mask>
+    <g id="shape-tab-audio">
+      <rect x="3" y="6" width="5" height="4" rx="1" ry="1" />
+      <polygon points="5.5,6.5 9,3 9,13 5.5,9.5" />
+      <path d="M 10,6.5 a 1.5 1.5 0 0,1 0,3 z" />
+      <path d="M 10,4 a 4 4 0 0,1 0,8 l 0,-1 a 3 3 0 0,0 0,-6 z"  clip-path="url(#clip-wave)" />
+    </g>
+    <g id="shape-tab-audio-muted">
+      <g mask="url(#disabled-cutout)">
+        <rect x="4" y="6" width="5" height="4" rx="1" ry="1" />
+        <polygon points="6.5,6.5 10,3 10,13 6.5,9.5" />
+      </g>
+      <line x1="3" y1="14" x2="13" y2="4" stroke-width="1.5" />
+    </g>
+  </defs>
+  <use id="tab-audio" class="icon" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-hover" class="icon hover" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-pressed" class="icon pressed" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-muted" class="icon muted" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-hover" class="icon muted hover" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-pressed" class="icon muted pressed" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-dark" class="icon dark" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-dark-hover" class="icon hover dark" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-dark-pressed" class="icon pressed dark" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-muted-dark" class="icon muted dark" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-dark-hover" class="icon muted hover dark" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-dark-pressed" class="icon muted pressed dark" xlink:href="#shape-tab-audio-muted" />
+</svg>
\ No newline at end of file
diff --git a/application/palemoon/themes/shared/tabbrowser/tab-audio.svg b/application/palemoon/themes/shared/tabbrowser/tab-audio.svg
new file mode 100644
index 0000000000..1949c0595f
--- /dev/null
+++ b/application/palemoon/themes/shared/tabbrowser/tab-audio.svg
@@ -0,0 +1,86 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="16" height="16" viewBox="0 0 16 16">
+  <style>
+    use:not(:target) {
+      display: none;
+    }
+    .icon {
+      fill: #666;
+    }
+    .icon.hover {
+      fill: #4d4d4d;
+    }
+    .icon.pressed {
+      fill: #000;
+    }
+    .icon.dark {
+      fill: #999;
+    }
+    .icon.dark.hover {
+      fill: #b2b2b2;
+    }
+    .icon.dark.pressed {
+      fill: #fff;
+    }
+    .muted {
+      opacity: .7;
+      stroke: #666;
+      stroke-width: 0;
+    }
+    .muted.hover {
+      opacity: .85;
+      stroke: #4d4d4d;
+    }
+    .muted.pressed {
+      opacity: 1;
+      stroke: #000;
+    }
+    .muted.dark {
+      stroke: #999;
+    }
+    .muted.dark.hover {
+      stroke: #b2b2b2;
+    }
+    .muted.dark.pressed {
+      stroke: #fff;
+    }
+  </style>
+  <defs>
+    <clipPath id="clip-wave">
+      <path d="M 10,7 l 3,-8 l 2,0 l 0,18 l -2,0 l -3,-8 z" />
+    </clipPath>
+    <mask id="disabled-cutout">
+      <rect width="16" height="16" fill="#fff" />
+      <line x1="4" y1="14" x2="14" y2="4" stroke="#000" stroke-width="2" />
+    </mask>
+    <g id="shape-tab-audio">
+      <rect x="2" y="5" width="6" height="6" rx="2" ry="2" />
+      <polygon points="4,6 9,2 9,14 4,10" />
+      <path d="M 10,7 a 1 1 0 0,1 0,2 z" />
+      <path d="M 10,5 a 3 3 0 0,1 0,6 l 0,-1 a 2 2 0 0,0 0,-4 z"  clip-path="url(#clip-wave)" />
+      <path d="M 10,3 a 5 5 0 0,1 0,10 l 0,-1 a 4 4 0 0,0 0,-8 z" clip-path="url(#clip-wave)" />
+    </g>
+    <g id="shape-tab-audio-muted">
+      <g mask="url(#disabled-cutout)">
+        <rect x="3" y="5" width="6" height="6" rx="2" ry="2" />
+        <polygon points="5,6 10,2 10,14 5,10" />
+      </g>
+      <line x1="2" y1="13" x2="14" y2="3" stroke-width="1.5" />
+    </g>
+  </defs>
+  <use id="tab-audio" class="icon" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-hover" class="icon hover" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-pressed" class="icon pressed" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-muted" class="icon muted" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-hover" class="icon muted hover" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-pressed" class="icon muted pressed" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-dark" class="icon dark" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-dark-hover" class="icon hover dark" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-dark-pressed" class="icon pressed dark" xlink:href="#shape-tab-audio"/>
+  <use id="tab-audio-muted-dark" class="icon muted dark" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-dark-hover" class="icon muted hover dark" xlink:href="#shape-tab-audio-muted" />
+  <use id="tab-audio-muted-dark-pressed" class="icon muted pressed dark" xlink:href="#shape-tab-audio-muted" />
+</svg>
\ No newline at end of file
diff --git a/application/palemoon/themes/windows/browser.css b/application/palemoon/themes/windows/browser.css
index e4f5f679f8..613dba9897 100644
--- a/application/palemoon/themes/windows/browser.css
+++ b/application/palemoon/themes/windows/browser.css
@@ -2018,6 +2018,78 @@ richlistitem[type~="action"][actiontype="switchtab"] > .ac-url-box > .ac-action-
   list-style-image: url("chrome://global/skin/icons/close-inverted.svg");
 }
 
+/* Tab sound indicator */
+.tab-icon-sound {
+  -moz-margin-start: 4px;
+  width: 16px;
+  height: 16px;
+  padding: 0;
+}
+
+.tab-icon-sound:not(:-moz-any([soundplaying],[muted])),
+.tab-icon-sound[pinned] {
+  display: none;
+}
+
+.tab-icon-sound[soundplaying] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio");
+}
+
+.tab-icon-sound[soundplaying]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-hover");
+}
+
+.tab-icon-sound[soundplaying]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-pressed");
+}
+
+.tab-icon-sound[muted],
+.tab-icon-sound[blocked] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted");
+}
+
+.tab-icon-sound[muted]:hover,
+.tab-icon-sound[blocked]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-hover");
+}
+
+.tab-icon-sound[muted]:hover:active,
+.tab-icon-sound[blocked]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-pressed");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark-hover");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[soundplaying]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-dark-pressed");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked],
+#TabsToolbar[brighttext] .tab-icon-sound[muted] {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked]:hover,
+#TabsToolbar[brighttext] .tab-icon-sound[muted]:hover {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark-hover");
+}
+
+#TabsToolbar[brighttext] .tab-icon-sound[blocked]:hover:active,
+#TabsToolbar[brighttext] .tab-icon-sound[muted]:hover:active {
+  list-style-image: url("chrome://browser/skin/tabbrowser/tab-audio.svg#tab-audio-muted-dark-pressed");
+}
+
+.tab-icon-sound[soundplaying-scheduledremoval]:not([muted]):not(:hover) {
+  transition: opacity .3s linear var(--soundplaying-removal-delay);
+  opacity: 0;
+}
+
 /* Tab scrollbox arrow, tabstrip new tab and all-tabs buttons */
 
 .tabbrowser-arrowscrollbox > .scrollbutton-up,
diff --git a/application/palemoon/themes/windows/jar.mn b/application/palemoon/themes/windows/jar.mn
index eb5edb3c12..724bac6899 100644
--- a/application/palemoon/themes/windows/jar.mn
+++ b/application/palemoon/themes/windows/jar.mn
@@ -150,6 +150,8 @@ browser.jar:
         skin/classic/browser/tabbrowser/tab-arrow-left-inverted.png  (tabbrowser/tab-arrow-left-inverted.png)
         skin/classic/browser/tabbrowser/tab-overflow-border.png      (tabbrowser/tab-overflow-border.png)
         skin/classic/browser/tabbrowser/tabDragIndicator.png         (tabbrowser/tabDragIndicator.png)
+        skin/classic/browser/tabbrowser/tab-audio.svg                (../shared/tabbrowser/tab-audio.svg)
+        skin/classic/browser/tabbrowser/tab-audio-small.svg          (../shared/tabbrowser/tab-audio-small.svg)
 #ifdef MOZ_SERVICES_SYNC
         skin/classic/browser/sync-throbber.png
         skin/classic/browser/sync-16.png