diff --git a/Systems/cfm56-sound.xml b/Systems/cfm56-sound.xml
index 4aa99597..5d46eb97 100644
--- a/Systems/cfm56-sound.xml
+++ b/Systems/cfm56-sound.xml
@@ -1083,6 +1083,121 @@
     </output>
 </filter>
 
+<!-- external buzz -->
+<filter>
+    <type>gain</type>
+    <gain>1</gain>
+    <input>
+		<condition>
+			<not><property>sim/current-view/internal</property></not>
+		</condition>
+        <expression>
+            <product>
+                <table>
+                    <product><property>/engines/engine[0]/n1-actual</property><value>0.01</value></product>
+                    <entry><ind>0.65</ind> <dep>0.00</dep></entry>
+					<entry><ind>0.70</ind> <dep>0.10</dep></entry>
+					<entry><ind>1.02</ind> <dep>0.80</dep></entry>
+                </table>
+            </product>
+        </expression> 
+    </input>
+	<input>
+		<condition>
+			<property>sim/current-view/internal</property>
+		</condition>
+		<expression><value>0</value></expression>
+	</input>
+    <output>
+        <prop>a320/sound/xbuzz-left-v</prop>
+    </output>
+</filter>
+
+<filter>
+    <type>gain</type>
+    <gain>1</gain>
+    <input>
+		<condition>
+			<not><property>sim/current-view/internal</property></not>
+		</condition>
+        <expression>
+            <product>
+                <table>
+                    <product><property>/engines/engine[1]/n1-actual</property><value>0.01</value></product>
+                    <entry><ind>0.65</ind> <dep>0.00</dep></entry>
+					<entry><ind>0.70</ind> <dep>0.10</dep></entry>
+					<entry><ind>1.02</ind> <dep>0.80</dep></entry>
+                </table>
+            </product>
+        </expression> 
+    </input>
+	<input>
+		<condition>
+			<property>sim/current-view/internal</property>
+		</condition>
+		<expression><value>0</value></expression>
+	</input>
+    <output>
+        <prop>a320/sound/xbuzz-right-v</prop>
+    </output>
+</filter>
+
+<filter>
+    <type>gain</type>
+    <gain>1</gain>
+    <input>
+		<condition>
+			<not><property>sim/current-view/internal</property></not>
+		</condition>
+        <expression>
+            <product>
+                <table>
+                    <product><property>/engines/engine[0]/n1-actual</property><value>0.01</value></product>
+                    <entry><ind>0.70</ind> <dep>0.80</dep></entry>
+					<entry><ind>1.02</ind> <dep>1.28</dep></entry>
+                </table>
+            </product>
+        </expression> 
+    </input>
+	<input>
+		<condition>
+			<property>sim/current-view/internal</property>
+		</condition>
+		<expression><value>0</value></expression>
+	</input>
+    <output>
+        <prop>a320/sound/xbuzz-left-p</prop>
+    </output>
+</filter>
+
+<filter>
+    <type>gain</type>
+    <gain>1</gain>
+    <input>
+		<condition>
+			<not><property>sim/current-view/internal</property></not>
+		</condition>
+        <expression>
+            <product>
+                <table>
+                    <product><property>/engines/engine[1]/n1-actual</property><value>0.01</value></product>
+                    <entry><ind>0.70</ind> <dep>0.80</dep></entry>
+					<entry><ind>1.02</ind> <dep>1.28</dep></entry>
+                </table>
+            </product>
+        </expression> 
+    </input>
+	<input>
+		<condition>
+			<property>sim/current-view/internal</property>
+		</condition>
+		<expression><value>0</value></expression>
+	</input>
+    <output>
+        <prop>a320/sound/xbuzz-right-p</prop>
+    </output>
+</filter>
+
 <!-- internal sounds -->
 <filter>
     <type>gain</type>