diff --git a/api/audio/echo_canceller3_factory.cc b/api/audio/echo_canceller3_factory.cc
index 7df43b3fd4..d65a7262fa 100644
--- a/api/audio/echo_canceller3_factory.cc
+++ b/api/audio/echo_canceller3_factory.cc
@@ -20,11 +20,6 @@ EchoCanceller3Factory::EchoCanceller3Factory() {}
 EchoCanceller3Factory::EchoCanceller3Factory(const EchoCanceller3Config& config)
     : config_(config) {}
 
-std::unique_ptr<EchoControl> EchoCanceller3Factory::Create(int sample_rate_hz) {
-  return Create(sample_rate_hz, /*num_render_channels=*/1,
-                /*num_capture_channels=*/1);
-}
-
 std::unique_ptr<EchoControl> EchoCanceller3Factory::Create(
     int sample_rate_hz,
     int num_render_channels,
diff --git a/api/audio/echo_canceller3_factory.h b/api/audio/echo_canceller3_factory.h
index 43f49a1b66..8b5380057b 100644
--- a/api/audio/echo_canceller3_factory.h
+++ b/api/audio/echo_canceller3_factory.h
@@ -28,12 +28,7 @@ class RTC_EXPORT EchoCanceller3Factory : public EchoControlFactory {
   // configuration.
   explicit EchoCanceller3Factory(const EchoCanceller3Config& config);
 
-  // Creates an EchoCanceller3 running at the specified sampling rate using a
-  // mono setup.
-  std::unique_ptr<EchoControl> Create(int sample_rate_hz) override;
-
-  // Creates an EchoCanceller3 running at the specified sampling rate using a
-  // multichannel setup.
+  // Creates an EchoCanceller3 with a specified channel count and sampling rate.
   std::unique_ptr<EchoControl> Create(int sample_rate_hz,
                                       int num_render_channels,
                                       int num_capture_channels) override;
diff --git a/api/audio/echo_control.h b/api/audio/echo_control.h
index 11ba989d7a..de80f500d1 100644
--- a/api/audio/echo_control.h
+++ b/api/audio/echo_control.h
@@ -52,14 +52,9 @@ class EchoControl {
 // Interface for a factory that creates EchoControllers.
 class EchoControlFactory {
  public:
-  virtual std::unique_ptr<EchoControl> Create(int sample_rate_hz) = 0;
-  // TODO(peah): Make pure virtual.
   virtual std::unique_ptr<EchoControl> Create(int sample_rate_hz,
                                               int num_render_channels,
-                                              int num_capture_channels) {
-    RTC_NOTREACHED();
-    return nullptr;
-  }
+                                              int num_capture_channels) = 0;
 
   virtual ~EchoControlFactory() = default;
 };
diff --git a/modules/audio_processing/audio_processing_impl.cc b/modules/audio_processing/audio_processing_impl.cc
index abfcc053d3..9a0ce88d56 100644
--- a/modules/audio_processing/audio_processing_impl.cc
+++ b/modules/audio_processing/audio_processing_impl.cc
@@ -1783,6 +1783,7 @@ void AudioProcessingImpl::InitializeEchoController() {
     if (echo_control_factory_) {
       submodules_.echo_controller = echo_control_factory_->Create(
           proc_sample_rate_hz(), num_reverse_channels(), num_proc_channels());
+      RTC_DCHECK(submodules_.echo_controller);
     } else {
       submodules_.echo_controller = std::make_unique<EchoCanceller3>(
           EchoCanceller3Config(), proc_sample_rate_hz(), num_reverse_channels(),
diff --git a/modules/audio_processing/audio_processing_impl_unittest.cc b/modules/audio_processing/audio_processing_impl_unittest.cc
index 5a2391b510..5707f470c8 100644
--- a/modules/audio_processing/audio_processing_impl_unittest.cc
+++ b/modules/audio_processing/audio_processing_impl_unittest.cc
@@ -53,10 +53,6 @@ class MockEchoControlFactory : public EchoControlFactory {
   MockEchoControlFactory() : next_mock_(std::make_unique<MockEchoControl>()) {}
   // Returns a pointer to the next MockEchoControl that this factory creates.
   MockEchoControl* GetNext() const { return next_mock_.get(); }
-  std::unique_ptr<EchoControl> Create(int sample_rate_hz) override {
-    RTC_NOTREACHED();
-    return nullptr;
-  }
   std::unique_ptr<EchoControl> Create(int sample_rate_hz,
                                       int num_render_channels,
                                       int num_capture_channels) override {