diff --git a/browser/devtools/webaudioeditor/test/browser.ini b/browser/devtools/webaudioeditor/test/browser.ini
index ca1ac106e11d..4090858f844f 100644
--- a/browser/devtools/webaudioeditor/test/browser.ini
+++ b/browser/devtools/webaudioeditor/test/browser.ini
@@ -28,6 +28,7 @@ skip-if = true # bug 1092571
 [browser_audionode-actor-add-automation-event.js]
 [browser_audionode-actor-get-automation-data-01.js]
 [browser_audionode-actor-get-automation-data-02.js]
+[browser_audionode-actor-get-automation-data-03.js]
 [browser_webaudio-actor-simple.js]
 [browser_webaudio-actor-destroy-node.js]
 [browser_webaudio-actor-connect-param.js]
diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-automation-data-03.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-automation-data-03.js
new file mode 100644
index 000000000000..13fb287b31c1
--- /dev/null
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-automation-data-03.js
@@ -0,0 +1,34 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test that `cancelScheduledEvents` clears out events on and after
+ * its argument.
+ */
+
+add_task(function*() {
+  let { target, front } = yield initBackend(SIMPLE_CONTEXT_URL);
+  let [_, [destNode, oscNode, gainNode]] = yield Promise.all([
+    front.setup({ reload: true }),
+    get3(front, "create-node")
+  ]);
+
+  yield oscNode.addAutomationEvent("frequency", "setValueAtTime", [300, 0]);
+  yield oscNode.addAutomationEvent("frequency", "linearRampToValueAtTime", [500, 0.9]);
+  yield oscNode.addAutomationEvent("frequency", "setValueAtTime", [700, 1]);
+  yield oscNode.addAutomationEvent("frequency", "exponentialRampToValueAtTime", [1000, 2]);
+  yield oscNode.addAutomationEvent("frequency", "cancelScheduledValues", [1]);
+
+  var { events, values } = yield oscNode.getAutomationData("frequency");
+
+  is(events.length, 2, "2 recorded events returned.");
+  is(values.length, 2000, "2000 value points returned");
+
+  checkAutomationValue(values, 0, 300);
+  checkAutomationValue(values, 0.5, 411.15);
+  checkAutomationValue(values, 0.9, 499.9);
+  checkAutomationValue(values, 1, 499.9);
+  checkAutomationValue(values, 2, 499.9);
+
+  yield removeTab(target.tab);
+});
diff --git a/toolkit/devtools/server/actors/webaudio.js b/toolkit/devtools/server/actors/webaudio.js
index 8aa610f2d8f1..b17db9ea1f0e 100644
--- a/toolkit/devtools/server/actors/webaudio.js
+++ b/toolkit/devtools/server/actors/webaudio.js
@@ -35,7 +35,7 @@ const NODE_CREATION_METHODS = [
 
 const AUTOMATION_METHODS = [
   "setValueAtTime", "linearRampToValueAtTime", "exponentialRampToValueAtTime",
-  "setTargetAtTime", "setValueCurveAtTime"
+  "setTargetAtTime", "setValueCurveAtTime", "cancelScheduledValues"
 ];
 
 const NODE_ROUTING_METHODS = [