diff --git a/api/audio/echo_canceller3_config.h b/api/audio/echo_canceller3_config.h
index dddc220d3b..f54ad908d0 100644
--- a/api/audio/echo_canceller3_config.h
+++ b/api/audio/echo_canceller3_config.h
@@ -47,7 +47,7 @@ struct RTC_EXPORT EchoCanceller3Config {
       int converged;
     } delay_selection_thresholds = {5, 20};
     bool use_external_delay_estimator = false;
-    bool downmix_before_delay_estimation = true;
+    bool downmix_before_delay_estimation = false;
     bool log_warning_on_delay_changes = false;
   } delay;
 
diff --git a/modules/audio_processing/aec3/echo_canceller3.cc b/modules/audio_processing/aec3/echo_canceller3.cc
index a68ae01a98..e387940885 100644
--- a/modules/audio_processing/aec3/echo_canceller3.cc
+++ b/modules/audio_processing/aec3/echo_canceller3.cc
@@ -51,6 +51,10 @@ EchoCanceller3Config AdjustConfig(const EchoCanceller3Config& config) {
     adjusted_cfg.erle.clamp_quality_estimate_to_one = false;
   }
 
+  if (field_trial::IsEnabled("WebRTC-Aec3AlignmentOnLeftChannelKillSwitch")) {
+    adjusted_cfg.delay.downmix_before_delay_estimation = true;
+  }
+
   return adjusted_cfg;
 }