diff --git a/libs/ardour/ardour/rc_configuration_vars.h b/libs/ardour/ardour/rc_configuration_vars.h
index 9c631b11ee..3169413821 100644
--- a/libs/ardour/ardour/rc_configuration_vars.h
+++ b/libs/ardour/ardour/rc_configuration_vars.h
@@ -178,6 +178,7 @@ CONFIG_VARIABLE (bool, never_display_periodic_midi, "never-display-periodic-midi
 CONFIG_VARIABLE (bool, sound_midi_notes, "sound-midi-notes", false)
 CONFIG_VARIABLE (bool, use_plugin_own_gui, "use-plugin-own-gui", true)
 CONFIG_VARIABLE (uint32_t, max_recent_sessions, "max-recent-sessions", 10)
+CONFIG_VARIABLE (double, automation_thinning_factor, "automation-thinning-factor", 20.0)
 
 /* denormal management */
 
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 013e07ada5..ae668c8730 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -3579,6 +3579,8 @@ Session::config_changed (std::string p, bool ours)
 		last_timecode_valid = false;
 	} else if (p == "playback-buffer-seconds") {
 		AudioSource::allocate_working_buffers (frame_rate());
+	} else if (p == "automation-thinning-factor") {
+		Evoral::ControlList::set_thinning_factor (Config->get_automation_thinning_factor());
 	}
 
 	set_dirty ();